21. Cabinet Body

sa#index cabBodyMain cabinet building plans; WPC cabinet building plans; backbox building plans; dimensions, WPC cabinet/backbox We turn now to what is arguably the essential element of our project, the thing that makes it special and different from video-game pinball on a PC: the cabinet itself.
(If you want to jump straight to the measurements for cutting up the plywood, skip ahead to A plywood cutting plan.)
The goal for most of us is to replicate as closely as possible the exterior appearance of a real pinball machine. That's what I set out to do with my own virtual cab, and for the purposes of this section, I'll assume it's your goal as well. This section is therefore basically a guide to building an accurate replica of a Williams pinball machine cabinet from the 1990s, using the same materials and parts. The plan here isn't an exact replica, because a few customizations specific to virtual pinball are needed, but they're surprisingly few and minor. For the most part, you could work through this section to build a replacement cabinet for a real machine.
When I was building my own virtual machine, I discovered that the design of pinball cabinets is something of a secret art. It's not secret by any intention or conspiracy, exactly; it's just that there's a lot of knowledge in the design that doesn't seem to be written down anywhere. Anywhere we can look at, anyway; it probably is all recorded in lavish detail in old engineering diagrams and blueprints locked in a file cabinet somewhere, but those documents aren't available to hobbyists.
Owners of the real machines can absorb a lot of the design details of the cabinets through observation, but if you don't have a real machine to take apart and examine, you pretty much have to guess. I'm fortunate to have some real machines at home, and that turned out to be a huge help for building a virtual cab. Whenever I was unclear on something, I could look at the real ones to see how they did it. I took advantage of that many times. So my goal in this section is to pass along as much of that secret knowledge as I can, in this one place, in an order that essentially provides a recipe for building one of these machines.
Not everyone wants their cab to look exactly like a real machine. Even if you're aiming for something novel, though, it can be helpful to understand how the standard design works. Many of the elements are the way they are because certain constraints had to be solved, and the modern cabinet design is the result of decades of refinement. You can always look to the standard design for ideas when you run into geometry constraints of your own.

Build, buy, or convert?

There are three main options for creating the body of your cabinet:
  • Build it yourself from scratch
  • Buy a new empty pinball cabinet, pre-built or as a kit
  • Convert an old real pinball machine into a virtual cabinet
If you're new to virtual pinball, the approach that might seem most appealing at first glance is to convert an old real machine. Indeed, this was the most popular approach in the early days of virtual cabs. It has the advantage that it's already a perfect match to the real thing from the very outset. It also saves you the trouble of coming up with the cabinet design from scratch - figuring dimensions, identifying and source parts, etc.
The conversion approach was popular for a while, but it's become a lot less appealing lately because of increasing prices. Pinball has become a collector's item, so even a beat-up old machine can command a pretty high price from someone looking for a restoration project. If you're lucky enough to find a donor machine that no one wants to restore, it'll probably be in such bad cosmetic condition that it might actually be cheaper and easier to start from scratch. (You should also be prepared for some negative comments on the forums, since there's a growing preservationist sentiment, even among the virtual pinball crowd. Many people see pinballs from past decades as works of historical significance that can't be fully or genuinely re-created once lost.)
Happily, the "build" and "buy new" alternatives are both quite practical, and I consider both of them superior to conversion, even without the price considerations. You can buy high-quality reproduction cabinets that look exactly like the real thing, and you can get these in kit form or fully assembled. Or, if you have some basic woodworking skills, you can build an excellent reproduction cabinet yourself. The real machines use fairly simple designs that you don't have to be a master carpenter to reproduce. This section provides detailed plans for building a faithful reproduction of the late-model Williams cabinet design.
What's more, it's easy to obtain all of the genuine cabinet hardware (metal rails, legs, etc) needed to fit out a custom-built cabinet and make it look exactly like a real machine. All of the hardware is very standardized across machines, and several big online pinball suppliers sell the parts. You can thank the collectors for that - they buy these parts to repair and restore their machines, so there's a healthy market in the parts that keeps them readily available.
Here are my recommendations:
  • For most people, I recommend using a VirtuaPin flat-pack kit. I used this approach myself, and I'm very happy with the results. It's not the cheapest option, but it's reasonably priced, and it yields an excellent finished product without requiring any real woodworking skills. With a little care, the result will be essentially indistinguishable from a brand new real pinball machine cabinet.
  • If you enjoy wood-working and have a well-equipped workshop, consider a scratch build. Doing it yourself is cheaper than buying a VirtuaPin flat pack, assuming you already have the tools needed, and you should be able to get equally professional results with a little care. Pinball cabinets are relatively simple as carpentry projects go; they're built out of ordinary plywood, and the woodworking involves only straight cuts and some basic joinery work. But even though the wood-working is pretty simple, you'll need to execute it with precision, so this is best if you already have at least a modest amount of wood-working experience.
  • If you don't want to do any woodworking, and you don't even want to assemble a kit, you can order a fully built cabinet from VirtuaPin or from a number of other vendors. VirtuaPin's pre-assembled product is the best one I've seen, and it's the only one I know of that faithfully reproduces the design of the real pinball machines. (In fact, it's such a good replica of the Williams 1990s design that some collectors restoring real machines buy them as replacement cabinets.) The products I've seen from other vendors use idiosyncratic designs and non-standard trim hardware, so they don't look to me quite like the real thing. If that's important to you, take a close look before buying to make sure you like the design.
  • I generally don't recommend trying to re-purpose an old real pinball as a virtual cab, in part because old cabinets tend to be so beat up that restoration would be more labor-intensive than building a new one, and in part because the economics rarely pan out. More on that below.

Economics of new vs used

If you're set on the idea of re-purposing a used cabinet, I'd suggest doing a little research first to make sure you don't overpay. The question you want to ask is: would I actually save money buying the used cab, or would it be cheaper to buy the same parts new?
To answer this, ask the seller for a list of all the hardware parts that the used cabinet includes - the legs, side rails, lockbar, etc. Don't assume that everything is included, because a lot of eBay sellers strip all of the parts out and sell them separately; a used cabinet might not come with anything beyond the wood box. And only consider the hardware that you'll actually use on your virtual cab, since those are the only parts you'd have to buy if you were starting from scratch. Only count parts that you actually need in the virtual cab (e.g., don't count the playfield, bumper caps, etc), and only count used parts if they're in usable condition.
To help you get started here's a list of the main parts that real machines and virtual cabs have in common. See Cabinet Parts List for a more detailed parts list with descriptions. We left the price column blank, since prices obviously vary over time and from one vendor to the next, so you'll have to fill that in by checking current prices at your preferred vendor(s) (such as VirtuaPin, PinballLife, or Marco Specialities). For the "wood body" line item, you can use VirtuaPin's flat pack or unfinished cab body offerings for comparison. Remember, only include the parts that the seller is including with the new cab, since you want to compare new-vs-used for what you're actually getting from the seller.
Add up the prices of the new parts, and compare the result to the seller's asking price for the used cab. If the asking price for the used cab is cheaper than the new parts, and everything's in good enough shape that you can actually use it, you've found a good bargain. If the seller is asking more for a beat-up used cab than what you'd pay new, I'd pass on the deal.
Description Price New
Main cabinet wood body $
Backbox wood body $
Legs (qty 4) $
Leg levelers ("feet") (qty 4) $
Leg brackets (qty 4) $
#8 x 5/8" wood screws for leg brackets (Williams ref 4108-01219-11, 4608-01081-11), or #10 screws if preferred (qty 32) $
Leg bolts (⅜"-16 x 2¾" or 2½") (qty 8) $
Side rails (qty 2) $
Lockdown bar $
Lockdown bar receiver $
Coin door $
Coin acceptors ("coin mechs") $
Cashbox tray (Williams ref 03-7626) $
Cashbox lid (Williams ref 01-10020) $
Cashbox nest bracket (Williams ref 01-6389-01) $
Cashbox lock bracket (Williams ref 01-10030) $
Carriage bolts, black, ¼"-20 x 1¼" (qty 6: 4 for coin door + 2 for lock bar) $
Flange locknuts, ¼"-20 (qty 6: 4 for coin door + 2 for lock bar) $
Top glass $
Rear plastic channel for glass $
Side rail plastic channels for glass (qty 2) $
Plunger (ball shooter) assembly $
Ball shooter mounting plate (Wiliams ref 01-3535) $
#10-32 x ¾" bolts for mounting plunger assembly (qty 3) $
Backbox hinges (qty 2) $
Backbox hinge backing plates (qty 2) $
Carriage bolts, ¼"-20 x 1¼" (qty 6, for backbox hinges) $
Flange locknuts, ¼"-20 (qty 6, for backbox hinges) $
Pivot bushing carriage bolts (qty 2) $
Hex pivot bushings (qty 2) $
Backbox latch $
Backbox latch bracket $
Backbox lock plate assembly $
U-channel, metal, ⅝" x ⅝" x 27⅛" (backbox speaker panel holder) $

Where to find used machines

Your best bet for finding a used machine at a good price will be local sellers. Search your local craigslist and local newspaper classified ads. A particularly good place to find a deal is at an estate sale. Heirs often want to clear out the house quickly and won't have any sentimental attachment to an old pinball.
If you can't find anything locally, eBay will give you access to sellers nationally (and even internationally). But I wouldn't get my hopes up; it's hard to find a good deal on a used cab on eBay these days. For one thing, shipping a cabinet is expensive due to the size and weight; shipping can add about $400 to the price. For another, eBay sellers know they can get top dollar for used cabs, so the base price is unlikely to be a bargain. Most eBay sellers are also savvy enough to strip a machine of all of the parts and sell them off separately, which largely defeats the purpose of reusing an old machine.

Kits and pre-built cabinets

If you can't find or don't want to use a salvage machine, but you also don't want to build everything from scratch, there are several companies that will sell you a brand new cabinet. For options, search the web for "new pinball cabinet" or "pinball cabinet restoration". One vendor I can recommend from personal experience is VirtuaPin. They sell cabinets in both kit form and fully assembled, and can customize them to your specifications.
You should be able to find options ranging from "flat pack" kits that you assemble yourself, to fully assembled cabinets with all of the hardware and artwork installed.
The cheapest and most DIY option is a flat pack kit. This is like an Ikea bookshelf: it consists of the wood parts, pre-cut and pre-drilled, ready for you to assemble. This is the cheapest kit option, since you provide the assembly labor, and because shipping is cheaper than for a bulky assembled cab. The degree of difficulty is slightly higher than for assembling Ikea furniture, but only slightly; no real woodworking skills are required, and you'll just need basic tools like screwdrivers and hammers. You might also have to do some sanding to even out corners and edges. And you'll have to do your own finish work (painting, staining, or applying decals). I used the VirtuaPin flat-pack kit for my own cabinet, and I highly recommend it. They use a good furniture-grade plywood, and the design is an extremely faithful reproduction of the WPC cabinets that Williams shipped in the 1990s, so the result is exactly like a brand new real machine.
The next step up in price and completeness is an assembled cabinet shell. This is just the wood shell, typically unfinished (ready for you to paint, stain, or apply decals), and without any of the cabinet hardware accessories installed. This eliminates the assembly work required for a flat pack. It's considerably more expensive to ship because it's so bulky.
At the high end price-wise, you can buy a fully assembled cabinet with all of the hardware and graphics pre-installed. VirtuaPin sells these in addition to their flat-pack and assembled-but-unfinished products. All of the VirtuaPin options use the same materials and design as their flat pack, so they all yield excellent reproductions of the 1990s Williams machines. There are other vendors selling pre-built cabinets as well, but check their designs carefully before buying, because I've seen a couple of other vendors who use their own ad hoc designs that look a bit cheap and cheesy to my eye.
Tip: Ask about the button hole layout. If you order a kit or pre-built cabinet, ask the seller for details on the locations of button holes they pre-drill, and ask them to customize the drilling to your plans if you have something else in mind. The vendor might drill holes by default that you don't want. Pay particular attention to the placement of the plunger and flipper button holes. Many virtual cab builders choose non-standard locations for these to accommodate the playfield TV (see "The dreaded plunger space conflict" in Playfield TV Mounting and "Positioning the plunger" in Plunger). If you're not sure how you want to handle this at the time of your order, you can simply ask the vendor not to drill any holes for the plunger or other controls. That will give you the flexibility to drill them yourself later when you know how everything will fit together.

Scratch build

If you have the necessary wood-working skills and tools, the cheapest and possibly best option is to build the whole thing yourself from raw materials. It's easy to get all of the parts and materials needed for an extremely accurate replica.
Here are the recommended wood materials:
  • ¾" (nominal) plywood, for almost all of the main cabinet and backbox. Choose a high-quality plywood that's graded for furniture or cabinetry use. The ¾" thickness is important, as many of the trim parts and controls (like flipper buttons and plunger) are designed to fit into ¾" walls. It's just barely possible to fit everything into a single 4' x 8' sheet if you make the cabinet floor out of something else (such as particle board). If you have the budget, I'd recommend getting two sheets of plywood and using it for the cabinet floor. This cabinet floor will be stronger, plus you'll have enough plywood left over for one or two "do-overs", which is a nice bit of insurance in case you make any mistakes or find any cosmetic flaws in the plywood.
  • ¾ particle board or fiberboard (e.g., MDF), only if you want to use it instead of plywood for the cabinet floor. The real pinball machines did this to save on cost, since the cabinet floor isn't a cosmetic element and no one cares if it looks cheap. Even so, I'd use plywood instead, since it's lighter and stronger. Particle board is likely to sag over time, and it doesn't hold screws very well.
  • ½ (nominal) plywood, for the back wall of the backbox. A 4' x 4' half sheet is sufficient.
  • A length of 2x2 (nominal) wood strip, in a soft wood like pine, for some miscellaneous parts. (A nominal 2x2 is actually 1.5" on a side.) You'll only need about two feet of this for the parts we make in this section, but I ended up using a bunch of this in my own cab for improvised connectors and supports and what have you, so you might want to pick up a few strips to have on hand.
  • A length of 1x2 (nominal) wood strip, in a soft wood, for a trim piece in the backbox. (A nominal 1x2 is actually .75" x 1.5".) You'll need about 3'.
Some people use MDF (fiberboard or particle board) instead of plywood for the entire cabinet. I strongly recommend using plywood instead. It's what all real pinball machine bodies are made of, and it's simply a much better material for this job. The main virtue of MDF is that it's cheap. It's also very uniform, which makes it attractive for some applications, but that's not particularly helpful for this project. The downsides of MDF are that it's very heavy, and it's not as sturdy or as durable as plywood. The weight difference is a significant factor for this project because it's a very large piece of furniture; a pinball body built from plywood is already plenty heavy.
(Despite what I just said about the evils of MDF, the original William cabinets actually did use particle board in two places: the cabinet floor, and the back wall of the backbox. I have to assume this was a cost-cutting measure, based on the idea that these surfaces don't have to look pretty because they're not visible to players. I'm normally all for meticulous adherence to the originals, but in this case I don't see any merit to it; the originals would have been better if they'd used plywood instead, as it's not uncommon in old pinballs for the MDF floor to sag in the middle.)
"Nominal" in lumber dimensions means that it's what the lumber yard calls it, but it's not the true size. Plywood is generally 1/32" thinner than the nominal thickness, and dimensional lumber, such as 1x2 or 2x2 strips, is generally 1/4" to 1/2" less in each dimension than the nominal size. So when the list above calls for 3/4" plywood, it means you should buy what the lumber yard calls 3/4" plywood, even though the true thickness will be slightly less than that.
For the woodworking, you'll need some basic power tools:
  • Drill
  • Wood-drilling bits, various sizes from 1/8" to 1/2"
  • Hole saws or Forstner bits, 1" and 1⅛" diameter. These are special types of drill bits, for standard portable drills and drill presses, designed to drill clean holes at larger diameters. You'll want to use these for anything larger than about 1/2" diameter. Spade bits are also available in these sizes, but they're not good for plywood because they cause a lot of chipping and tear-out. A hole saw or Forstner bit will produce much cleaner results.
  • Jigsaw
  • Plunge router. This isn't something most casual woodworkers own, but if you do buy one, I expect that you'll find it so useful that you'll wonder how you ever lived without it. A router is pretty much required if you're going to build a cab from scratch. A plunge router is a hand-held router whose bit can move perpendicular to the work surface, so that you can position the bit at a starting point above the surface, and then "plunge" it straight down into the surface to begin cutting. Routers are good for cutting grooves, insets, and openings in arbitrary shapes. They can also cut the edges of a board into different shapes, for joining pieces at corners.
  • 3/32" slot cutter bit for your hand router. This is a special type of router bit that's needed to cut slots along the top edges of the side walls, for installing the playfield glass channels. See Freude part number 63-106 for an example.
  • Circle jig for your hand router. This is an attachment for the router that lets you cut circular patterns in a range of sizes. This is good for cutting large circular openings (larger than a drill bit can make). We'll need this to create openings for the subwoofer and the ventilation fans.
  • Table router. This is useful for cutting long straight lines and for making joinery edges. A hand router can do these jobs, too, but some tasks are easier with a table router.
  • Circular saw, table saw, or track saw, with a fine-tooth blade. This is optional, but it's what most people use for the long, straight cuts for the main pieces. You can alternatively use a jigsaw or router instead.

    The default saw blades that come with most circular saws are for coarse cuts, and they won't work well with plywood. So you'll probably also need to buy an extra blade that's specifically designed for plywood and designated as a "finish" blade. The manufacturer should list the materials that the blade is designed for in the product description. "Finish" blades are designed to make clean cuts with minimal chipping; they usually have a lot of small teeth.

  • Power sander. There's enough sanding needed in a cab build that the job will be infinite if you try to do it by hand. A power sander makes much lighter work of it and produces better results.
You'll also need the cabinet hardware parts. Many of these are specialized pinball parts, which are available as replacement parts from arcade supply vendors. See Cabinet Parts List for the full parts list, with part number references for standard pinball parts.
I personally prefer to use real pinball parts wherever possible, instead of trying to improvise something out of common hardware parts. It can be a bit more expensive to use the real parts, but they tend to look better, and in many cases they're easier to work with because they're purpose-built for a specialized job. That said, a fair number of the parts that go into a cab are truly generic hardware, like nuts and bolts, that you can buy anywhere; there's no reason to buy special pinball-certified #8 machine screws, for example. But even some of the generic-sounding hardware can be hard to find outside of pinball vendors. Anything that I listed with a Williams part number in the master list (Cabinet Parts List) is probably one of those hard-to-find items.

Choosing a cabinet design

As far as I'm concerned, there's only one cabinet design that we need to concern ourselves with: the "WPC" cabinet. This is the cabinet that Williams (and its co-brands Bally and Midway) used for all of their machines in the 1990s. The name comes from the electronics platform used in that generation of machines, which was called the Williams Pinball Controller or WPC.
One good reason to use the WPC cabinet design is that it's by far the easiest to find parts for. Machines from this generation are still widely deployed and remain some of the most popular pinballs of all time, so there's plenty of demand for replacement parts from owners of the real machines. If you design to the WPC specs, you'll be able to use these readily available parts to outfit your machine. Using the real parts will give your machine a completely authentic look, and it's a lot easier than fabricating your own custom metal parts.
Another reason to use the WPC cabinet plan is that it's the same plan used by most real machines from the modern era. Williams used it for nearly all of their 1990s machines. Stern's 2000s machines are built to almost identical plans, as are the machines from the boutique pinball makers like Jersey Jack and Spooky Pinball. This cabinet style is what you'll see almost every time you encounter a late-model pinball in an arcade or bar. A virtual cab following the same plan will look exactly like what everyone expects a real pinball machine to look like.
For a DIY project, you're always free to come up with something completely different, either to fit your particular needs or purely to be unique. I personally place a lot of value on simulation fidelity, so I like the idea of a virtual machine looking as much as possible like a real machine. But that's just me; you might have other priorities or different taste. If you have other ideas for how your cabinet should look, you can take as much or as little from the WPC design as suits you.
We provide detailed plans for the standard WPC design later in this section. Before we get to the plans, though, there are some variations that you might want to consider, so that you can customize the plans for your project's specific goals.

Standard and Wide-body cabinets

The WPC design is what we usually call the "standard" cabinet, because Williams/Bally/Midway used this for most of the machines they shipped in the 1990s. However, they also used a variation of this plan that differed by making the main cabinet wider. This wider variation was used for seven titles in all: The Twilight Zone (1993), Indiana Jones: The Pinball Adventure (1993), Judge Dredd (1993), Star Trek: The Next Generation (1993), Popeye Saves the Earth (1994), Demolition Man (1994), and Red & Ted's Road Show (1994). Williams marketed these seven games as "Superpin" machines, so the wider cabinet style is sometimes called the Superpin cabinet, but everyone in the virtual pinball world calls it the "wide-body" cabinet. (Actually, everyone calls it the "widebody", unhyphenated, but my spell-checker disapproves, so I'm using the hyphen here.)
The wide-body design is identical to the standard WPC cabinet in every particular, except for the width of the main cabinet, which is 2¾ inches wider than the standard body. All of the other dimensions are exactly the same as in the standard body. The backbox size is identical in both versions. (A lot of people assume that wide-body WPC machines had extra-wide backboxes as well, but they didn't. They used the same backbox dimensions as the regular WPC machines. So there's really no such thing as a "wide-body backbox", at least as far as the original WPC machines go.)
The wide-body machines obviously require wider variations for some of the hardware trim parts, to match the wider cabinet dimensions. If you build your own wide-body design, you'll need to get the wide-body versions of the affected parts. Be aware that the wide-body trim parts can be a little harder to find and a bit more expensive than the standard-body parts. Fortunately, you don't actually need very many wide-body-specific trim parts for a wide-body cabinet, thanks to the way they kept everything except the width the same as the normal cabinets. The only special wide-body trim parts required are the "lockdown bar" (the metal trim piece across the top front of the machine, also known as the front molding) and the glass cover.
The lockdown bar is mated with a second piece known as the "lockdown bar receiver", which doesn't require a separate wide-body version. The standard receiver works with both standard and wide-body lockbars.

Custom width

In addition to the WPC standard-body and wide-body designs, there's a third option for custom builders: you can design a cabinet with a completely custom width that doesn't match either of the official Williams designs.
The main reason to build to a custom width is to get an exact fit for your playfield TV. It's not possible to order a TV in a bespoke size; we can only buy what the TV manufacturers offer on the mass market. We can, however, build our cabinets to whatever sizes we want. So some people build their cabinets to fit their top TV pick, rather than settling for TV that only approximately fits one of the standard cabinet sizes.
Customizing the width has implications for the associated cabinet hardware, obviously, since off-the-shelf parts are only available in the standard sizes. To minimize these implications, you can use the same principle that Williams did when they designed the wide-body variation: as long as you keep all of the other dimensions the same, you can change the cabinet width to any size desired, and the only custom hardware required will be the lockdown bar and the cover glass.
The lockdown bar is the main challenge. Fortunately, there is a source for custom-width lockdown bars: VirtuaPin. They're the only source of these I know of, so hopefully they'll keep selling them. Expect to pay about double the price of the standard-size lockdown bar (which I think is a pretty reasonable premium, considering that it has to be custom-made on demand).
Note that the lockdown bar is mated with a second part known as the "lockdown bar receiver". The receiver does not need to be customized for different widths; the standard receiver will work with any lockbar width, as long as your cabinet is wide enough (minimum 19½ inches inside width) to accommodate it. (This is no problem if you're making a wider-than-standard cabinet, but keep the minimum size in mind if you're designing a miniature cabinet that's narrower than usual.)
The glass cover is easy to order in a custom size, and won't cost any more than a standard size. Don't bother looking at online pinball vendors; simply order from a local window glass supplier. Any glass shop should be able to fabricate a custom glass sheet for you in almost any desired size. Once you know the inside width of your cabinet, order a tempered glass sheet in the required width, by 43" length, by 3/16" thickness.
When calculating the required width of your glass, take into account the overhang beyond the inside dimensions. The easy rule of thumb is to make the glass ½" wider than the inside width of your cabinet (that is, the distance between the insides of the side walls). For example, the standard body cabinet has an inside wall-to-wall width of 20½ inches, so the standard playfield glass is 21" wide.
One more tip about ordering custom glass: ask the vendor to omit any marking or etching that identifies the glass as tempered. Glass shops will often include a special marking on tempered glass to certify building-code compliance, in case you're planning to use it for something like a shower enclosure where tempered glass is legally required. But a marking like that can be an eyesore in a virtual cab; it might end up in a corner where it's in plain view. Tempered glass is good for a virtual cab for safety reasons, but there's no legal requirement for it, and thus no need for certification marks.

How to choose a cabinet width

If it weren't for the constraint of fitting a TV, I'd just tell you to use the standard-body plan and leave it at that. Using the standard dimensions produces a machine with exactly the right proportions to look like authentic, and lets you use readily available off-the-shelf parts for all of the hardware. It's the easiest approach and yields great-looking results.
But sadly, TV manufacturers don't always cooperate with our virtual pinball plans. TV manufacturers only make TVs in certain sizes, so we're stuck with whatever sizes are on offer. The TV you pick based on price and performance might not be available in exactly the right size for a standard cabinet.
What size TVs will the standard cabinet sizes accommodate? There's no absolute rule here, since the nominal diagonal size of a TV doesn't tell you the exact exterior dimensions - the only way to be sure is to measure the TV. (You might also be able to find the dimensions listed in the specs on the manufacturer's Web site or on a retailer site.) Generally speaking, a standard-body cab will accommodate most 39" TVs, and can handle some 40" models, and a wide-body can handle most 45" TVs.
My personal preference is to try to stick to the standard-body width if at all possible, meaning that I'd try to find a 39" TV that fits the standard cab's 20½" inside width. I prefer the proportions of the standard cabinet as a matter of aesthetics. If the TV you want to use is only available in a larger size that won't fit the standard-body design, I'd switch to the WPC wide-body, since it works with entirely off-the-shelf cabinet hardware. I'd accept the trade-off of some "dead" space in the cabinet if the TV didn't quite fill the full wide-body width, to keep the cabinet hardware standard.
I'm personally a little leery of building a cab to a custom size, not so much because of the extra cost of the custom parts (which really isn't all that huge a difference), but because it could preclude ever replacing or upgrading the TV. The odds are against any future model having exactly the same dimensions. At the very least, you won't be able to get the glove-like fit that made you choose the custom size in the first place.

Custom length

As long as we're on the subject of custom widths, we should consider lengths as well.
As with a custom width, the main reason to build to a custom length is make a TV fit exactly. As discussed in Selecting a Playfield TV, a real pinball playfield is much more elongated than a 16:9 TV screen; a typical 1990s era playfield is more like 20:9. So placing a 16:9 TV in a standard-sized cabinet leaves a few inches of dead space at the front and/or rear of the cabinet. Some cab builders don't like that idea because they want to fill every square inch with TV display area.
One way to deal with the extra space is to remove it by shortening the cabinet length to exactly fit the TV.
In my opinion, it's better to stick with the standard cabinet length and accept that there will be some extra front-to-back space. The main problem with a custom length is that you won't be able to find side rails or glass guides; no one sells those in custom sizes as far as I know, and they'd be difficult to fabricate yourself unless you have some good metal-working tools. Besides, the extra space can be put to good use for features that you might want anyway:
  • If you're going to install a plunger, you might need 3-4" of extra space between the front of the TV and the front of the cab to make room for the plunger mechanism.
  • Even if you don't need the space for a plunger, I still like setting the TV back a few inches from the front for the sake of sight-lines, so that you don't have to look straight down to see the flippers.
  • Space at the front of the TV can be used for an "apron" similar to that on a real machine, with printed instruction cards, or even small monitors that display live instruction cards, scores, etc.
  • Space at the back of the TV can be used for a flasher panel or LED matrix.

Custom backbox sizes

As with the main cabinet dimensions, some virtual cab builders choose to deviate from the standard backbox sizing to better fit a selected TV.
Finding a backbox TV that fits the available space can be even more vexing than finding a playfield TV. There are two big problems here. The first is proportions: modern TVs all use the 16:9 aspect ratio, but the translites in the WPC design are much squarer: approximately 13:9, closer to the old-fashioned NTSC 4:3 ratio. The second problem is that there are very few models available that are even close to the right size. 32" is an extremely popular size, but sadly, a 32" is much too wide for a standard backbox. The next size down tends to be 27" or 28". A 28" TV will leave about an inch of dead space on each side, and a few inches above and below. A 29" would be close to perfect, but at the moment those just don't exist.
You can't control what sizes the TV manufacturers make available, so you can either live with a little dead space around the perimeter, or you can resize the backbox to fit the TV. I personally think the dead space is the better compromise, in part because it lets you use standard off-the-shelf pinball parts, but mostly because the backbox shape will look "wrong" if you change it from the standard. This is a case where I think a lot of cabinet builders tend to fixate on the wrong thing during the planning stages, by focusing on the dead space rather than the overall proportions. The thing that you might not appreciate during the planning stage is that any dead space tends to disappear into the background when you're actually playing. Your eye sees what's there (the backglass graphics), not what's missing (the dead space around the edges). The proportions of the overall outline, on the other hand, are always noticeable.
If you do want to consider custom dimensions for the backbox, keep in mind that some of the associated hardware parts are sized for the standard dimensions, so you might not be able to use off-the-shelf parts for everything. Here are the parts that will be affected (see the illustration below if you're not familiar with all of these):
  • The glass or plexiglass cover for the TV. This isn't a required part, but I recommend including it because it creates a more authentic appearance. There's no downside to a custom size for this part, because it doesn't come in an off-the-shelf version to begin with; you'll have to custom-order it even if you're using the standard size. You can have this made at any local window glass shop or plastics store, and they'll be able to cut it to whatever size you need.
  • Trim pieces for the glass/plexi cover. Real pinball machines use black plastic trim around the edges of the translite. These are only available in the standard sizes. You can fairly easily cut them to smaller lengths if necessary, but there's no good way to make them longer, so you'll have to live with some gaps if you use a wider or taller than normal size.
  • Speaker panel "H" channel and translite lift trim. These are plastic trim pieces that go at the top of the speaker panel and bottom of the translite, respectively, and they're sized to the standard width. If you use a wider-than-normal width, you can use the standard pieces, but there will be some gaps at the edges.
  • Speaker panel. If you use a non-standard width, you'll need a custom speaker panel, assuming you're using the three-monitor configuration. No one sells those in custom sizes, so you'll have to fabricate one yourself. The ready-made speaker panels are made from plywood or particle board, so building your own only requires woodworking tools. Be aware that it's a fairly advanced project requiring precision work. You'll have to cut two large circular holes the speakers and a large rectangular opening for DMD. I'd recommend using a CNC machine (a computer-controlled cutting machine that cuts according to a digital plan). There are online services for this, such as SendCutSend. If you live in or near a major city, you might also be able to find a local CNC service, or a "maker" facility that lets you use their equipment for an hourly fee.

Mini cabs

A popular variation on the basic cab design is to scale things down a bit from the real machines. This can be especially attractive if you don't have a lot of space in your house, since a full-sized cab is a rather large and imposing piece of furniture. Downsizing a bit might also help gain acceptance from spouses and other family members who aren't as enamored with pinball as you are.
There's no "standard" mini-cab design, but you can find ideas from other people's builds by searching the cab forums at sites like vpforums. Many people who've built their own cabs post build logs with details of their design.
If you want to design a mini-cab from scratch, you can start with the basic WPC design, and just scale down all of the dimensions based on the playfield monitor you choose. A 32" TV makes a good core to build a mini-cab around; if you scale everything down proportionally, it yields a cab that's about 3/4 of the full size. That's enough of a reduction to fit more comfortably into a residential setting, but it's still big enough to be free-standing.
A few people on the forum have shrunk things down even further, to table-top or hand-held size, using a small computer monitor or tablet as the playfield.
For a mini-cab in the 3/4 scale range, you should be able to build it pretty much the same way that you'd build a full-size cabinet. You'll have to make the same adjustments to cabinet hardware discussed above under "custom width" and "custom length", but otherwise you should be able to use standard materials (such as ¾" plywood for the enclosure) and many of the standard hardware parts. One thing to keep in mind is that interior space will be a bit tight for the electronics, but you should be able to fit the necessary computer parts and a basic set of feedback devices.
If you reduce the scale to table-top or hand-held dimensions, you'll have to invent a lot more of the design on your own, since most of the standard hardware will be too large. That's beyond the scope of this guide, but you should be able to find one or two examples in the forums or elsewhere on the Web if you're looking for inspiration. Note also that all of the pinball software discussed in this guide is for Windows PCs, so if you're considering something else (like a tablet or Raspberry Pi) as the computer core, you'll also have to find other software to use. There are some decent commercial pinball games for tablets that could serve, but the commercial games don't tend to have any integration with cabinet features, so it might be challenging to make everything work the way you want it to.

WPC cabinet plans

We now present our WPC standard-body cabinet plans. These are based primarily on measurements taken from actual WPC pinball machines, with some additions and modifications to accommodate the peculiarities of virtual pinball. I've tried to identify all of the deviations from the real machines, for those with a special interest in accurately re-creating the originals.

Other Internet plans

There are several other pinball cabinet plans available on the Web, including other replica WPC designs. Some of the other WPC plans I've seen have slight variations from mine, so you might want to compare and contrast any others you find as a sanity check, and to see if there's anything you prefer in the variations. I've taken a great deal of care to check my plans against actual WPC machines, and I believe the version presented here is the closest to the real thing that I've seen, but of course that doesn't mean they're the ideal plans for every build, just that they're close to what Williams actually did build. You might have good reasons to deviate from that. Most of the details can be changed in small ways without much affecting the usability of the finished machine. (One usability detail that think you should avoid tinkering with unless absolutely necessary is the placement of the flipper buttons: that's very uniform on the real machines, so players are likely to notice a difference in how it feels if you change this more than very slightly.)
One set of alternative plans that I'll call out in particular is Jonas Kello's Sketchup model, available on github:
The nice thing about his 3D model is that you can look at it from different angles, which might be helpful whenever my illustrations leave something unclear about spatial relations between components. Jonas's model appears to have been prepared with excellent attention to detail. One warning, however: he explains that he took physical measurements from a wide-body WPC machine (Star Trek: The Next Generation) and adjusted them to the standard-body dimensions. This creates an opportunity for errors and inconsistencies to creep in, and in fact I came across a couple of errors in his model that are clearly due to this. My measurements were taken from actual standard-body machines (Theatre of Magic and Medieval Madness), so while I'm sure I have some errors and mis-readings of my own, my readings at least are free of that particular source of error. I also noticed some very slight variations (on the order of 1/16" to 1/8") between some of my measurements and Jonas's, which I'm sure can be attributed to some combination of our respective judgment calls squinting at the ruler, and variations in the original manufacturing. Williams historically used multiple subcontractors to produce their cabinets and playfields, so I imagine there had to be some variations from unit to unit for any given game, let alone different titles manufactured years apart.

Joinery

In wood-working, joinery is the art of forming joints where pieces of wood meet. There's a lot more to this than just nailing boards together; joins can involve angled edges to hide seams, and interlocking tabs and slots to add strength. Joinery is a huge subject that goes well beyond my expertise, so I won't try to offer a primer here. However, I do want to provide a quick overview of the way that the corner joints work in the real pinball machines, because you might want to adapt these - either to something simpler, if you don't have the right tools for the typical pin cab joins, or to something better, if you have other styles you prefer.
Apart from the corner joins, most of the joins we use in the plans are straightforward enough that you probably won't need to change them. Most of the joins (save the corners) are simple dado or rabbet joins that you can execute with straight router bits or a table saw.
Now, on to the main cabinet corner joins, where the walls meet at right angles. There are several ways to execute these, and you'll see a few different approaches in the real machines, depending on manufacturer and era. The most sophisticated join I've seen in pin cabs is the one used in the WPC cabinets of the 1990s: a lock miter join, which looks like this (viewing the front left corner from above):
Lock miter join, at the front left corner of the main cabinet, viewed from above. This is the type of join that Williams used for the original WPC cabinets from the 1990s.
This is a really nice join aesthetically, since it makes the seam invisible by placing it exactly at the corner. It's also extremely strong, thanks the large glue surface area from the interlocking tabs. But it's a highly challenging bit of carpentry - even a lot of experienced woodworkers consider it difficult. You need a special router bit to cut it, and it's notoriously hard to get the positioning of the cuts just right. What's worse, even with the right tools and skills, you still might not be able to get it to work with some plywood, since the plies might not be strong enough for the thin cuts. The advice I've seen on most carpentry forums is that this join is great for solid wood, but not always suitable for plywood. The owner of Virtuapin, which sells reproductions of the Williams cabinets, has said that Williams was only able to make the lock miter work on their cabinets because the plywood of that era was better than today's. My own experience has been a bit better than that - I've made it work nicely with Home Depot plywood - but I can attest to how challenging it is to get the router bit set up properly.
An easier alternative is a mitered rabbet, which combines a miter joint (a 45° diagonal cut at the corner) and a rabbet (a squared recess along one edge):
Mitered rabbet join, at the corner between the front wall and left wall of the cabinet.
Top view of the front section, with a mitered rabbet at each corner.
The mitered rabbet has the same aesthetic advantage of the lock miter, placing the seam exactly at the corner, but it's easier to execute, it's more plywood-friendly than the lock miter because it doesn't have such small structures.
To cut a mitered rabbet, you can buy a special router bit set just for this join, or you can cut it in multiple passes with a couple of basic bits: a 45-degree chamfer bit and a straight bit. The procedure is beyond what I can include here, but you should be able to find tutorials and instruction videos about it on the Web easily, since it's a popular joint for general woodworking.
If the degree of difficulty were no obstacle, I'd definitely go with one of the joins illustrated above (the lock miter or mitered rabbet). They both have the virtue of being cosmetically seamless, thanks to the 45° diagonal cut to the outside corner. Both are strong joins that fit precisely and self-align; assembling pieces made with these joins is like snapping together puzzle pieces.
Despite the virtues of the mitered joins, they might not be your top choice because of how challenging they are to cut. If you want something simpler, the alternative I'd use is a double rabbet.
The double rabbet join dispenses with the diagonal cut out to the corner, and instead uses square interlocking notches. The big advantage is that it can be implemented with common tools (a table saw or a straight router bit). But it has a couple of drawbacks. For one, it leaves a visible seam along one of the joined faces. For another, it makes it a little trickier to translate the cabinet measurements to the wood pieces, because of the way one piece slightly extends the apparent length of the adjoining piece.
Double rabbet join, similar to the join used in Williams System 11 cabinets. This is a simpler alternative to the lock miter join used in the WPC cabinets, but it has the drawback that it leaves a seam along one face near the corner.
Williams used something similar to the double rabbet join in their System 11 machines in the 1980s, and VirtuaPin uses it in their reproduction cabinets and flat packs, so it certainly qualifies as a professional-grade option. And it's a good join functionally - it's strong and makes a reasonably precise fit. But a rabbet join leaves that visible seam, so I consider the mitered options to be superior, if you have the tools (and patience) for them.
If you do decide to use the double rabbet join, there are a couple of things you can do to minimize the visibility of the seam. First, choose the placement of the seam so that it's on the less visible face. The seam only affects one or the other adjoining face at each corner, so you have a choice of which wall will have the seam. The Williams System 11 cabinets placed the seams on the sides (rather than the front face), which seems like the better choice aesthetically, since the front is more visible. Second, cut the front piece a tiny bit wider (1/16", perhaps) than the final size, so that it leaves a little overhang when initially assembled, as illustrated below.
After assembly, the overhang lets you sand down the excess material until it's exactly flush with the adjoining section. It's almost impossible to get the surfaces perfectly flush in the initial cut, so your best bet is to start with a slight overhang that you can sand until flush. You can then add wood filler at the seam to further smooth it out.

Adjusting dimensions for joinery

Pay close attention to the effects of your chosen corner joins on the overall dimensions.
The dimensions shown in our plans assume that you're using the joinery specified. In the case of the corner joins between the side walls and the front and back walls, this means we assume you're using one of the mitered joins we described above, either the lock miter or mitered rabbet. (Our illustrations use the mitered rabbet for the main cabinet corners, so you'll see that join in the close-ups. The lock miter is equivalent in terms of all of the measurements, so there's no need to make any adjustments if you use the lock miter instead.)
With the mitered joins, note how each piece's dimensions from corner to corner exactly match the assembled cabinet's outside dimensions for that section:
In contrast, with the rabbet join, note how the "inside" piece (the one forming the face with the seam) is slightly shorter than the assembled cabinet's outside dimensions. This will be shorter at each corner by the depth of the rabbet groove, which is typically half the plywood thickness, so assuming there's a join like this at each end, the overall piece will need to be cut shorter than the desired final outside dimensions by 2 × ½ × the plywood thickness = 1 × the plywood thickness:
Our measurements for the main cabinet are based on using mitered joins at the visible corners, so be sure to adjust the dimensions before cutting if you're using a different join.

Edge finishes

On the original WPC cabinets, the outside bottom edges of the side and front walls are finished with a chamfer (a 45° bevel), about ⅛" wide. The point is simply to make the plywood edge less sharp and splintery. A softer edge is less likely to snag on clothing or give you a splinter. It also protects the plywood from chipping.
The chamfer is just one way to soften the edge. Alternatively, you can go over the edge with a roundover router bit to give it a curved edge, or smooth it out with a power sander. You can also just leave it square if the sharp edge doesn't bother you.
The WPC machines had square corners for the front vertical edges (at the corners between the front wall and the left and right walls). Some of the newer Stern machines round those out slightly. If you want rounded corners, you can go over the corners with a roundover router bit after assembly. I'd at least use a power sander to smooth the corners a little, but I wouldn't try to achieve visible curvature that way, since it's hard to make it uniform. Use a router if you want a pronounced curve.

Exploded view

This view shows all of the pieces making up the main cabinet body.
The triangular wood pieces at the corners are for the leg fasteners. Metal fastener plates fit over these on the inside, and two bolts go through each one at a 45° angle to the adjacent walls.
The two pieces at the top rear form a "shelf" that the backbox rests on. The rectangular routed opening in the horizontal piece is to pass power and video cables between the cabinet and backbox. The opening shown is what's used on the real machines, and it works well for a virtual cab as long as you only need to pass cables through. You might need a larger opening, though, if you plan to use a large monitor in your backbox that needs to extend into the main cabinet. This isn't an issue for a typical three-monitor setup with a laptop display for the DMD (or a real DMD device).
The smallish slat near the bottom front attaches to the floor on the real machines to form a niche to hold the cashbox. (The cashbox sits under the coin slots to collect the inserted coins.) Most virtual builds omit this piece to leave more room for the PC motherboard, which most people situate on the floor of the cab about halfway back.

A plywood cutting plan

Here's my plan for cutting up the plywood sheets. I won't claim that this is the best possible way to fit all of the pieces together, but it's a pretty efficient fit, and it doesn't require too many individual cuts.
This plan assumes that you're making the cabinet floor out of plywood (rather than particle board), so it's designed for two 4x8 sheets. If you make the floor out of particle board, though, it's just barely possible to fit everything else into a single 4x8 sheet; see Single-sheet layout below.
Before using this plan literally, please be sure to make any adjustments necessary for differences in your cabinet layout. In particular:
  • Please read the notes above, under Joinery, about adjusting the dimensions of the cabinet pieces if you're planning to use rabbet joins or butt joins. The dimensions in the diagram assume miter joins for the cabinet corners, where all of the outer faces extend all the way to the corners. Don't make the same adjustment for the backbox; my backbox plan only uses rabbet join to start with.
  • The dimensions shown are for a standard-body WPC cabinet. If you're building a wide-body cabinet or a custom-width cabinet, you'll need to adjust the width of the front panel, back panel, and rear shelf. The plan shown has room to widen those by about 5 inches, which is wide enough for a WPC wide-body (add 2¾" to the standard body width).
Each piece also requires routing for joinery and drilling for buttons and other attachments. The details are explained piece-by-piece in the sections below. Instructions for assembling the pieces into the final cabinet follow all of that. (The assembly process itself is almost easy once you have everything cut and routed, but it takes a little work to get there.)
Don't start by marking all of those cut lines on the plywood sheet. That won't produce accurate results, because your saw blade will remove some of the material between the pieces at each cut, which you can't easily account for in the initial marking. What works better is to make one cut at a time, and then measure the next cut from the newly cut edge. That ensures that the saw blade width is automatically accounted for at every stage, without any tricky calculations or estimates. The step-by-step instructions below use this approach.
Also, to make sure that your saw blade's width is accounted for in each cut, always align the saw on the "outside" of each cut, so that the blade's width is positioned in the "leftover" portion of the plywood rather than within the work piece you're cutting. Align the edge of the blade on each cut with the outside edge of the work piece.
Step-by-step procedure:
Plywood sheet #1 - 4' x 8' x 3/4" nominal thickness. Dimensions are all for the WPC standard-body design, so be sure to make appropriate adjustments if you're building a wide-body cab, a custom-width cab, or you're using a non-standard length. Click image for full-sized version.
1. Measure from one edge of the sheet to 51-1/2", to the cut line marked "A" in the diagram above. Cut across the whole sheet on this line. Set aside the smaller portion.
2. We're now going to cut the diagonal line "C" for the side panels. On the "A" cut line, measure 15-3/4" to the point labeled "X", and mark that spot. On the opposite side, pencil in the line marked "B", 7-1/8" from the edge. ("B" is just a reference point - don't cut along this line.) Then measure 23-1/2" along "B" from the edge to the point labeled "Y", and mark that spot. Draw the diagonal line "C" through points "X "and "Y". Cut all the way along "C".
3. The piece you just cut out is one side wall of the cabinet. You just need to cut out that 7-1/8"-long flat portion where the diagonal edge flattens out. Mark a line 23-1/2" from the opposite side, parallel with the opposite side, and cut along that line to make the flat portion. The finished side piece should look like this:
4. On the remaining piece, you can repeat the measurements from step 2 to mark the 51-1/2" line "D", or you can simply use the finished first side piece as a template, since both sides should be identical. Either way, mark line "D" and cut along the line to cut out the second side piece.
5. Repeat step 3 with the second side piece to cut the 7-1/8" flat portion.
6. From the remains of the 51-1/2"-wide section, cut the two small rectangular pieces shown at the bottom: the cashbox fence (20-1/2" x 3"), and the rear shelf lip (20-3/8" x 2").
7. Now we'll work on the (almost) half-sheet that was left over from the first step, after cutting along line "A". This section should be about 48" x 44". Mark cut line "E" by measuring 21-7/8" from one edge.
For wide-body or custom cabinets, adjust this dimension! 21-7/8" is for the WPC Standard Body design, which fits the standard Williams lockbar (Williams/Bally part number D-12615, A-18240). If you're building a wide-body that's matches the original Williams "Superpin" cabinet, to fit the off-the-shelf WPC wide-body lockdown bar (A-16055, A-17996), the width should be 24-5/8". If you're building to a custom size, you can determine the width to use here by adding 1-3/8" to your desired inside cabinet width (the distance between the inside faces of the side walls - essentially, the width available for the main TV).
Make sure the board is oriented so that "E" goes down the longer (48") dimension! Otherwise you won't have enough material for the three pieces shown.
8. Using the 21-7/8" section we just cut, mark line "F" 23-1/2" in from one edge. Cut along this line. This yields the back wall of the cabinet.
9. Continuing with the remainder of the 21-7/8" section, mark line "G" 7-1/8" from one edge. Cut along this line. This yields the rear shelf for the cabinet.
10. Still using the remainder of the 21-7/8" section, mark line "H" 15-7/8" from one edge. (This will use almost the entire rest of the piece, but there should be just enough left that you still have to trim this little bit.) This line should be cut with the saw tilted at a 10° angle. The saw should be tilted so that the face you cut through ends up as the larger face, taking the angled cut into account. The opposite face should only be 15-3/4" wide when done, due to the angled cut. If your saw only tilts in the opposite direction, so that the far face will end up being wider, you should mark line "H" at 15-3/4" to compensate. Here's the side profile of the finished piece, to give you a better idea of what we're going for:
If your saw can't easily cut at an angle like this, you can get away with making a square cut. Cut the piece at the shorter 15-3/4" size in this case. The angle is to make the top edge of the piece align with the diagonal slant of the cabinet sides, so that all the edges are flush. But this isn't actually all that critical; it's only a slight aesthetic imperfection if you can't make the edges flush, and it's an imperfection you'll almost never have to look at anyway, since the whole area is covered by the lockbar! The only time you'll see it is when you take the lockbar off to get inside for service.
11. There are only two pieces left to cut out of the remainder of the first plywood sheet: the sides of the backbox. The leftover piece should be about 22" x 48" (or less than 22" if you're building a wide-body or wider-than-standard-body cabinet). Mark line "J" by measuring 28-1/2" from one edge. Check that your saw is set back to 0° for a square cut. Cut along line "J".
12. On the 28-1/2" piece we just cut, mark the diagonal line "K" by measuring a point 10" from a 28-1/2"-long edge at one end, and 6-1/2" from the same edge at the other end. Cut along this line. This yields the first backbox side piece.
13. On the other piece, you can either repeat the measurement to mark the square line "L", or you can use the first backbox side piece as a template to mark the cut line, since the two sides are identical. Cut along the line.
We're finished with the first plywood piece! Time to move on to the second sheet.
Plywood sheet #2 - 4' x 8' x 3/4" nominal thickness. The dimensions are based on the WPC standard-body cabinet plan, so adjust the cabinet floor size if you're building a wide-body cabinet or using a custom width or length. Note that the backbox dimensions don't change for the "Superpin" widebody design - those used the same standard backbox size as regular pins. However, adjust as needed if you're building a custom backbox (e.g., building it around a particular monitor size). Click image for full-sized version.
14. The first cut is the cabinet floor, which is a simple rectangular piece, 50-5/8" x 21".
The 21" dimension is based on the cabinet width, so adjust this for a wide-body or custom-width cabinet. If you're building to the Williams "Superpin" wide-body specs, make this 23-3/4". For a custom width, add 1/2" to the desired inside width of your cabinet (the space between the inside walls).
Note that the real pinball machines almost all used particle board for the cabinet floor instead of plywood, to reduce cost. The cabinet floor isn't visible to players, so they figured no one would care about cheap materials there. Even so, I think it's worth using plywood, since particle board tends to sag over time, and plywood is lighter.
15. The backbox top and bottom require another tilted-blade cut, so it's not quite as simple as cutting the rectangles shown. Start by cutting line "A", at 28" from one edge of the leftover from the cabinet floor.
16. Mark line "B", at 10" from a 28" edge of the 28"-wide piece we just cut. Set your blade to a 7° tilt.
The blade should be tilted so that the face you're cutting into will be the wider side. If your saw only tilts the other way, so that the opposite face will be the wider one after the cut, flip everything around and measure line "B" at 6-1/2" in instead of 10" in.
Once you have it set up, cut at line "B" with the 7° tilted blade.
This yields the backbox top (or the backbox bottom, if you had to flip things around for the 6-1/2" cut).
Sanity check on the angled cut: The result should be 10" side on one face, and about 9-29/32" wide on the opposite face. If you did the 6-1/2" cut, the result should be 6-1/2" wide on one face. and slightly wider, about 6-19/32", on the opposite face.
17. Set your saw back to 0° for square cuts. Orient the remaining piece so that the angled cut with the narrow face is facing the saw blade. Measure line "C" at 6-1/2" from the angled edge (or 10" from the angled edge if you flipped around in the previous step). Cut along this line. Make the same sanity check as in the previous step for the angled cut.
18. You're now done with the 3/4" plywood! There is more one bonus step, but for this, you need a sheet of 1/2" plywood (actually, just a half sheet will do). This is for the back wall of the backbox. This is just a simple rectangle, 28" x 27-3/4".
If you prefer, you can use your remaining 3/4" plywood for this piece, but remember to adjust the depth of the groove that you route in the backbox side, top, and bottom walls accordingly. The back wall fits into a routed groove at the back of those pieces, so the groove has to match the thickness of the back wall. You'll also lose 1/4" of space inside the backbox, of course, so make sure you can spare it - some TVs are a tight fit.
Plywood sheet #3 - 4' x 8' x 1/2" nominal thickness. Or, a 4' x 4' half sheet is sufficient. Click image for full-sized version.
19. Additional bonus steps: there are a few more miscellaneous pieces that you'll need to cut out of the remaining plywood plus other wood stock. These are covered in detail in the sections below, but here's a quick summary:
  • Two 3" lengths of nominal 2x2 stock, cut in half diagonally down its length, to secure cashbox fence
  • Four 6" lengths of nominal 2x2 stock, cut in half diagonally down its length, to reinforce the inside corners where the leg brackets attach
  • Two 4-3/4" x 3/4" strips of 1/2" plywood, for DMD panel guides
  • Two 15" x 3/4" strips of 1/2" plywood, for translite guides
  • One 27-1/8" x 3/4" strips of 3/4" plywood, for a translite guide
  • Two 12-3/8" x 1" strips of 3/4" plywood, for translite guides
  • One 27-1/8" length of 3/4" reducer molding (or a similar shape fashioned from a nominal 1x2), for backbox trim at the top of the translite
And, of course, the woodworking on the plywood pieces isn't finished after you cut the last piece. Most of these parts require some additional work with a router, drill, and/or jigsaw. The sections below have all the details, part by part.

Single-sheet layout

It's just barely possible to make all of the 3/4" panels fit into a single 4x8 sheet, as long as you make the floor out of something else, such as particle board or MDF. The real machines of the 1990s did just that, because no one cared if the floor looked cheap. If you're on a tight budget, you can save some money by doing the same thing.
Here's a cutting plan that fits everything into one sheet. You'll have to be very careful to minimize wasted material between cuts to make this work - there's very little room for error or waste, since everything is packed so tightly together. Also, I don't think there's any way to make this work for a wide-body plan, since it just barely fits with the standard width pieces. For dimensions, see the Sheet #1 and Sheet #2 plans above.
Alternative layout that fits everything into a single 4' x 8' sheet of nominal 3/4" plywood. This is based on the standard-body WPC cabinet dimensions; I don't think there's any room to expand the panels for a wide-body design. Click image for full-sized version.

Side walls

Here are the side walls. The views are from the interior of the cabinet, to show details on the joinery routing.
(The flipper button holes and leg bolt holes are marked, but for the sake of readability, the dimensions aren't shown here. We'll provide close-up diagrams for these elements, with all of the measurement details, later in the section.)
Left side wall, viewed from the cabinet interior side
Right side wall, viewed from the cabinet interior. The right wall is a simple mirror image of the left wall.
Remember that we're measuring the dimensions of the pieces based on a mitered join (either a mitered rabbet or lock miter) at the front and rear corners, meaning that the piece's dimensions match the outside dimensions of the assembled cabinet. If you're using a different join at the corners, be sure to make any necessary adjustments. See Joinery above.
Some more views to help with visualization:
The backbox pivot is a ½" hole for attaching the WPC-style backbox hinge. If you're using different hardware to attach the backbox, omit this.
The "dado" at the bottom is a groove to join with the cabinet floor. Use a ¾" router bit to cut a straight groove ⅜" deep (that is, halfway through the thickness of the plywood). This runs parallel to the bottom edge, ¼" from the bottom edge. This is on the inside of the wall; the cabinet floor slots into this groove when assembled.
Left cabinet wall showing the dado (groove) for joining with the cabinet floor. Route the dado with a ¾" bit to ⅜" depth, ¼" from the bottom edge. This groove runs the whole length of the side wall. This is on the interior face, since it joins with the cabinet floor. The diagonal/step shape along the vertical edge at the left is the mitered rabbet cut for joining to the front wall, illustrated in more detail above.

Edge finishes

The original WPC cabinets use a slight chamfer (a 45° bevel) on the outside bottom edges of the side walls, to soften the edge and reduce splintering. This is optional, but it will reduce the chances of snagged clothes and cuts from bumping into the side. See Edge finishes above.

Leg bolts

The leg bolt holes are a little tricky. The bolts go through the corners at a 45° angle, so they bore through both adjoining walls at each corner. So, as shown in the illustration, the left and right walls only have "half a hole" for each bolt - really more of a semicircular notch.
Leg bolt holes, front (above left) and rear (above right). The distances are shown from the bottom of the cabinet. Note that the front legs are mounted higher on the wall than the rear legs. The legs themselves are the identical parts front and back, so the different mounting position is used to give the cabinet its characteristic tilt angle. The bolt shafts are ⅜" diameter.
Cutaway view (with the front wall removed) showing the leg bolts installed, to better illustrate how the bolt holes intersect the side wall. The triangular wood piece that normally fills the gap between the metal plate and the inside wall is also hidden.
Illustration of how the leg install positions affect the cabinet slope. The legs are mounted higher on the cab in the front, which effectively raises up the back end slightly to slope the machine down toward the front. Standard pinball legs come with adjustable foot pads that you can use to make sure all four legs touch down and to fine-tune the playfield slope. The slope isn't needed for "physics" reasons on a virtual machine, but it's still desirable for an authentic appearance, and it also improves the viewing angle for the main TV.
There are two approaches to drilling the holes:
  • Before assembly, using a router to cut the "half holes" in each panel. The bolts are 3/8" diameter, so each "half hole" needs to be 3/16" deep and 3/8" wide. You can accomplish this using a 3/8" round-nosed router bit - this type of bit has a half-dome shape for its tip, so it routes half-cylinder grooves, exactly as we need. Route to a depth of 3/16".

    The 45° angle makes it extremely difficult to cut these with a hand router, so this is only feasible if you're using a table router or a CNC machine to make the panels.

  • After assembly, using a regular drill with a 25/64" bit to drill the holes. The 45° angle makes this a difficult job for a hand drill, but it's doable using a special jig that guides the bit at the proper angle. You can find general-purpose angle-drilling jigs at hardware stores and Amazon. Or you can build one yourself. Some people have successfully built such jigs using a couple of 2x4 blocks bolted together to make a corner. If you want something a little easier, here's a 3D-printable model for a jig that's set up with the proper spacing and angle:
With either method, the holes should end up being a tight fit for the bolts. That's good, since you don't want your 250-pound cabinet standing on wobbly legs. But the holes might end up being so tight that the bolts won't fit at all at first. If that's the case, use a small round file to expand the holes slightly. Ream out a little bit at a time and test the fit frequently with a bolt, stopping as soon as it fits.

Flipper buttons

Here's the drilling plan for a set of two flipper button holes on each side. The front button in each set is the regular flipper button, and the rear button is the "MagnaSave" button, which is for the benefit of some pinball games that have extra controls beyond the regular flipper buttons. The rear buttons are optional, and not everyone likes them since they're not all that common on real machines, but I think it's good to include them because of the large number of virtual tables that make use of them. See Tables with MagnaSave Buttons for more about these buttons, and a list of some of the tables that use them.
Note! Many older side rails (from before the WPC type) have pre-drilled holes for the flipper buttons. The WPC side rails don't need flipper button holes because they don't extend far enough down the side to cover the buttons, as most older rails do. If your rails cover the flipper button area, ignore our button drilling locations. Instead, use your side rails as drilling templates, since the holes in the cabinet will have to line up with the ones in the rails.
Flipper button drill hole detail for WPC-type side rails. Measurements are in inches; distances are to the center points of the holes. (Don't use these locations if you're using older side rails that cover the flipper buttons. Instead, use the pre-drilled flipper button holes in your rails as drilling templates, so that the cabinet holes line up with the holes in the rails.)
Drill the flipper button holes with a 1⅛-inch diameter hole saw or Forstner bit. The distances in the diagram are measured are from the center of the drill holes to the front and top edges of the wall, square with the front edge.
Variations:
  • The rear (MagnaSave) buttons are optional. If you don't want to include them, simply don't drill the holes. The regular flipper buttons go at the same position whether or not you include the MagnaSave buttons.
  • There are at least two other good ways to position the MagnaSave buttons. Some people place them directly below the flipper buttons, and some people prefer them diagonally behind and below the flipper buttons. Both of those patterns have precedents in real pinball machines that had the extra buttons (see Tables with MagnaSave Buttons). The layout in my diagrams is based on the Williams MagnaSave games from the 1980s, so it's probably the most familiar look to most players, but not everyone likes the feel, due to the stretch to reach the rear buttons. The more vertical layouts are arguably easier to reach, and make it it easier to keep a finger on each button.
  • Williams System 11 games (1980s) placed the flipper buttons about 1/4" higher than shown in my diagrams, which are based on the WPC games (1990s). System 11 games used broader side rails that covered the flipper buttons, so I think the slightly different positioning is purely to accommodate the different rails. I don't think it noticeably affects the feel.
How to drill: My preference is to simply drill a hole straight through with a 1⅛-inch hole saw or Forstner bit. On the Williams machines, they drilled a more complex pattern where they drill partway through from each face with a 1⅛" bit (5/16" deep from the outside, 3/16" deep from the inside), and go the rest of the way with a ⅝" bit. This matches the shape of the flipper button, which has a large outer section and a narrower stem, and it makes for a more secure attachment. The reason I prefer a 1⅛" diameter hole all the way through is that it makes it easier to install LEDs behind the button to illuminate it from the inside.
The distances shown are from the outside front corner of the finished cabinet. Assuming you're using a mitered rabbet join, that's the same as the outside front edge of the work piece, so you can simply measure from the front edge of the work piece. Be sure to make any necessary adjustments to the measurements if you use a different join type, so that the position of the holes ends up at the indicated distance from the outside front corner of the cabinet when assembled.

Glass channel slots

If you're going to install the standard side rails and a glass cover over the playfield, you should also install a set of "glass channels". These are plastic "U"-shaped trim pieces that fit under the side rails, along the left and right edges. These hold the glass at the sides.
Because the glass channels are "U" slots along the length of the machine, you can slide the glass in and out of the channels through the front of the machine, after removing the lockbar. This is part of the tried-and-true design of the real machines that lets an operator easily open up the machine for maintenance access, and I think it's a great thing to replicate in a virtual cab.
The glass channels are installed under the side rail. Here's a close-up of how they look when installed:
The channels attach to the side wall via a "spine" sticking out of the bottom of the plastic channel. The spine which fits into a slot in the top edge of the side wall.
This is a neat design, in that you don't need any fasteners or adhesives. You just press the spine into the slot, and it's held there by friction. If it's ever necessary to take the channel out, you can just pull it out. On the other hand, it presents us with another little wood-working challenge: how do we cut that precise little slot?
Fortunately, it turns out that there's a specific tool for this job, which make the slot really easy to cut. The tool is a special type of router bit called (naturally) a slotting cutter. These come in various slot widths and depths. For this job, you need a 3/32" slot width. Any depth ⅜" or higher should work. The exact bit I used for this when building my cab is Freude part #63-106.
Once you have the necessary slot cutter bit, cut a slot along the top edge of the sloped portion of each side wall, centered along the edge, starting about 1½" from the front and ending at the top of the sloped section. Cut the slot (at least) ⅜" deep.

Front wall

The front wall is the most complex section of the cabinet. It has a whole bunch of things attached: the coin door, several pushbuttons, the plunger, the lockbar, and the leg bolts. There are so many things vying for a limited amount of space that the positioning of each part is pretty constrained; everything fits together like a 3D puzzle.
I initially tried to cram all of the measurements for all of the cutouts into a single diagram, but I quickly abandoned that idea, since it was way too busy. So instead, I've broken it out into several diagrams, one for each set of cutouts. We'll start with the basic outline and its overall dimensions, with the purpose of each cutout labeled.
Main cabinet front panel, viewed from the front (exterior side).
Remember that we're measuring the dimensions based on a mitered rabbet join at the corners, and that you might need to adjust the dimensions slightly if you're using a different join style. See Joinery above.
More views for visualization:
The overall width is based on the standard-body design. If you're building a wide-body or custom-width cabinet, adjust the width of this piece accordingly. Keep the coin door cutout centered horizontally at the new width, and keep the buttons and plunger at the same distance from their respective side walls.
The dado at the bottom is for joining with the floor of the cabinet. This is exactly the same as the ones in the side walls: route a ¾" wide groove to a depth of ⅜" (half the thickness of the plywood) along the whole bottom edge, on the interior side, ¼" from the bottom.
The leg bolts go through the corners of the front face at a 45° angle, just like the way they work with the side walls. Route notches for the bolts exactly as we described earlier for the side walls. Use the same positioning (measured from the bottom edge) as for the front legs on the side pieces. The front notches in the side walls need to align with the notches in the front wall when the cabinet is assembled.
If you want to get fancy, cut the top edge of the front wall to match the slope of the side walls. The slope is 10°, which corresponds to a rise of about ⅛ over the thickness of the plywood. In other words, the height at the back face (the side facing the interior of the cabinet) should be about ⅛ taller than the height at the front face (the exterior side), as illustrated below.
Side view of front panel (viewed from right) showing the slight angle at the top, to match the slope of the side walls.
Cutting the top edge at angle as shown results in the best fit. But if you want to keep it simpler, I think it's okay to skip the angle and cut it square, using the shorter exterior height. Using a square cut means that the back top edge won't quite align with the top edges of the side walls. But this whole area is covered by the lockbar when the machine is assembled, so it'll only be visible at all when you remove the lockbar to access the interior. The gap won't affect alignments for any of the trim hardware, so it won't have any functional impact.
If you do use the sloping top edge, note that all of the measurements shown in our diagrams and plans are based on the front face - the shorter exterior side. Things will be off by ⅛" if you measure with reference to the top edge of the back side, since it's slightly taller. So be sure to do all of your measuring and drilling from the front side.

Edge finishes

The original WPC cabinets use a slight chamfer (a 45° bevel) on the outside bottom edge of the front wall, to soften the edge and reduce splintering. This is optional, but it's a little nicer than a sharp square plywood edge. See Edge finishes above.

Coin door cutout

The rectangular cutout in the center of the front wall is for a standard pinball coin door, of the style used on 1990s-2000s machines. All of the doors used by all of the manufacturers from the mid 1980s onward have the same dimensions, so you can use any late-model Williams or Stern parts. SuzoHapp makes a universal replacement door that fits the same cutout. Older doors from before the mid 1980s might have different sizes, so measure your actual hardware first if you're using an older model.
Note! The gaps between the coin door cutout and the four bolt holes around the perimeter are very small (only about 3/16"). Be as precise as you can when measuring, and be careful when drilling.
Coin door cutout and bolt locations, viewed from the interior face of the front panel. Important: the measurements referenced to the top edge will be slightly different (about 1/8" less) when measured on the exterior face, because of the angled cut on the top edge. The interior face is about 1/8" taller than the exterior face because of the slant.
The four 5/16"-diameter drill holes around the perimeter of the coin door cutout are for the carriage bolts that fasten the door to the plywood. Use ¼"-20 x 1½" carriage bolts for these. Mate them to ¼"-20 hex nuts, which go on the inside. The carriage bolts are available in black, which is what the WPC machines use to match the powder black finish of the WPC-style doors. The bolts are also available in stainless steel, chrome-plated steel, and silicon bronze, one of which might look nicer if you have a door with a metallic finish.
The coin door is usually centered left-to-right. If you're using a custom width, simply figure the position so that it's centered horizontally. Don't try to center it vertically, though. The vertical position has to align with your lockbar receiver, because the coin door's top center bolt hole has to align with the receiver's center bolt hole, as illustrated below.
If you're using the standard WPC-era parts (a 1990s coin door and a Williams WPC lockbar receiver), the vertical position shown in our diagrams should align the receiver properly. If you're using different parts, they might have a different design, so you might need to adjust the vertical position to match. See the "dry fit" procedure in the lockbar receiver section below for advice on how to figure the right position for different parts.
If you're not using a coin door at all, you should obviously omit the rectangular cutout, as well as the drill holes around the perimeter. Note that the top center hole is shared by the coin door and lockbar receiver, though, so if you're using a standard lockbar receiver, you'll still need to drill that hole even though you don't need it for the coin door.

Lockbar receiver

The three small drill holes shown at the top of the front wall plan are for the carriage bolts that fasten the lockbar receiver to the front wall. (If you're not sure what the receiver is or what it's for, we'll explain more about it shortly.)
As with the coin door, use the center point of the front wall (left to right) as the horizontal reference point for the center hole.
The receiver has to be positioned vertically so that the lockbar will fit properly when inserted into the receiver. The vertical position of the bolt holes in our plans is specifically for a Williams WPC lockbar receiver, to place it at the right height so that the lockbar will fit properly.
But be warned! Our plans assume that you're using the WPC lockbar receiver, and that you're using all of the mating parts, including standard side rails with glass guides. The thickness of the rails and guides is important to the overall positioning.
If any of this is different in your setup - different brand of lockbar, different generation, different side rails, no side rails - then you'll probably need to adjust the position. It's difficult to figure the right position on paper because there are so many factors. It's easier and more reliable to just measure it with a mockup or "dry fit" with all of the parts together. That means that you set up the parts in their assembled positions without actually gluing or fastening anything yet:
  • Set up the front and side walls in their assembled positions.
  • Set up the side rails with the glass guides, if they'll be part of the final setup.
  • Plug the lockbar into the receiver.
  • Position the lockbar at the top front where it'll be during normal use. You want the lockbar to sit snugly on top of the side rails when everything is put together, so at this stage it's a good simulation to simply set the lockbar on top of the rails.
  • Now hold the receiver's front surface flush against the inside front wall. Make sure the lockbar is still where you want it.
  • Mark the positions on the inside of the front wall corresponding to the positions of the three bolt holes in the receiver. (The bolt holes in the receiver are actually little slots, to give you a little wiggle room to make up for measuring errors, so mark the position at the center of each slot.)
You can now take it all back apart, and drill at the marked positions instead of the ones in the plans.
If you're not using a standard receiver, you can omit the left and right drill holes. The center hole is still needed for the coin door, if you're using one, even if you don't need it for a receiver.
In case you're not already familiar with how all of the pinball trim pieces work, here's a brief overview.
The "lockbar" (also known as the "lockdown bar") is the metal trim piece along the top front edge of the machine. It's so named because it serves to lock the top glass cover in place. It also functions as a trim piece, for the sake of appearance as well as to provide a comfortable place to rest your hands while operating the flipper buttons. Standard lockbars have nice smoothly rounded corners. Try playing a round on a machine with the lockbar removed if you want experience for yourself how unpleasant the plywood edges are as a hand-rest.
If you're using standard pinball parts, the lockbar mates with a part inside the cabinet called the "receiver". A couple of prongs that stick down out of the lockbar fit into receptacles in the receiver, where there are some spring-loaded latches that grab the prongs and secure the lockbar. A lever on the receiver, which you can reach through the coin door opening, lets you release the latches and free the lockbar. With the lockbar off, you can slide out the glass to access the interior. It's all cleverly designed to let an operator open up the machine quickly and without any tools, while keeping it buttoned up against intrusion by mischief-makers.
The receiver attaches to the inside of the front wall of the cabinet. It's fastened with three carriage bolts. This is what the drill holes at the top of the front wall are for. The center bolt is shared between the coin door and receiver - both parts have holes in this position that align when everything is assembled. This is why the vertical position of the coin door is so important: the coin door aligns with the lockbar receiver, and the receiver has to align with the top of the wall so that the lockbar fits properly.

Front panel buttons

The three large circular holes at the top left of the front panel diagram are for buttons that the player uses to start and exit games and otherwise interact with the software. Our plans assume that you're using SuzoHapp small pushbutton (pictured at right), which are the type used for most of the front-panel button on real machines since the 1990s. These are the exact type that most pinball suppliers will sell you if you buy a replacement Start button, Extra Ball button, or generic "pushbutton with lamp assembly". There are other similar buttons available from other companies that you can use as well, but you might need to adjust the drilling dimensions and/or spacing for other models.
Attention: Reproduction cabinet builders: If you're building a cabinet for a real pinball machine, you should adjust the button layout to match the original design of the machine you're reproducing. Take care to line up the button positions with corresponding designs in the artwork, if any.
For the standard pushbuttons, drill the holes in two stages. First, route a 1⅜"-diameter depression on the exterior face to about half the plywood thickness (⅜"). That's the larger circle depicted in each button hole. Then route or drill a 1" hole the rest of the way through, on same center as the routed depression. If you're using a drill, use a 1" hole saw or Forstner bit to do it cleanly. (Don't use a spade bit; spade bits make ragged holes in plywood.) The depression recesses the pushbutton enough that it's flush with the front surface of the cabinet, which makes for a nicely finished look.
Above left: Drilling detail for the button holes, viewed from the exterior face. Route a 1⅜" diameter depression to ⅜" depth (about halfway through the plywood). Drill a 1" diameter hole the rest of the wall through, on the same center, using a router or a drill with a hole saw or Forstner bit. Above right: when installed, the buttons are recessed in the routed depressions, so the button faces are roughly flush with the outer surface of the cabinet.
The routed depression is optional. It's the way that the buttons were mounted on the real 1990s machines, and I think it makes for a clean, finished look. But if you want to keep things simpler, you can skip the routed inset and simply drill a 1" hole straight through. The buttons will jut out by about a quarter inch if you omit the inset, but this won't look "wrong", since the buttons are trimmed to work with this mounting style as well.
Our plans show the positions for three buttons, but you can vary this slightly. As far as software usability goes, the virtual pinball software more or less requires a minimum of two buttons: "Start" and "Exit". The third button in our plans can assigned be any extra function of your choice. See Cabinet Buttons for recommendations. I think it's a good idea to include some third button even if don't have a clear use in mind, just for the sake of flexibility. I assigned my third button as "Extra Ball", since that's used on a lot of real machines from the 1990s. Another useful function is "Coin In" (to simulate inserting a coin), although I prefer implementing that via the coin return buttons on the coin door, since that's a more natural and inconspicuous place for it. In any case, if you change your mind about the button's function later, it's easy to reassign these buttons in software, and relatively easy to relabel them physically.
Omitting a button is easy. If you only want to include two buttons, simply drill the top two holes at the positions shown, and skip the bottom one.
Adding buttons is more difficult, as space is tight. With the three buttons positioned as shown, there's not enough room for a new fourth button at the top, since the lockbar receiver will get in the way, nor at the bottom, where the leg fasteners will conflict. However, you just barely make room if you move the top button up about ½" (that's the limit before it conflicts with the lockbar receiver) and then tighten up the spacing on the other buttons by about ⅛". That will give you just enough room for a fourth button at the bottom.

Plunger and Launch button

Our plan includes a traditional mechanical plunger, at the standard position used on nearly all real machines, at the upper right corner corner of the front face. We also include a Launch Ball button, situated just below the plunger, to accommodate tables that originally used a button or trigger in place of the traditional plunger.
Be aware that this traditional plunger position doesn't work for everyone! In particular, it can get in the way of the TV if you want to place the TV very close to the front wall. See "Other plunger/Launch button layouts" below for an alternative plan that swaps the positions of the plunger and launch button to make room for the TV. If you haven't thought about the TV conflict issue, see "The dreaded plunger space conflict" in Playfield TV Mounting and "Positioning the plunger" in Plunger.
Attention: Reproduction cabinet builders: If you're building a cabinet for a real pinball machine, be aware that the plunger position varies by machine, because it has to align with the shooter lane on the playfield. The position in my diagrams is based on measurements from a couple of WPC machines, but other titles might vary from the ones I sampled. System 11 machines generally need the plunger cutout to be about 1" higher because of the shorter playfield hanger brackets they use. Take measurements from the original cabinet you're replacing, if possible, or ask for help on an owners forum. fr
Drilling positions for plunger and Launch Ball button, with the plunger in the standard position used on real machines, and the Launch button below.
Drilling pattern for the plunger opening. Reference the vertical location from the main plan to the top dotted line. For the standard plunger-on-top configuration, this is 2½" from the top of the panel.
To cut the plunger opening:
  • Drill a ¾" hole at the large green circle at top center. It's best to use a router, or a drill with a hole saw bit or Forstner bit. (Don't use a spade bit; they make ragged, chipped holes in plywood.)
  • Drill ⅜" holes at the three smaller green circles.
  • Use a jigsaw to cut along the perimeter of the shape described by the four holes, shown as the black outline on the diagram.
The illustration at right shows how this looks when assembled.
This arrangement with the plunger on top and a Launch button below is the one I prefer. It has two main virtues. First, it looks like it should, because the plunger is at exactly the standard position used in practically all real machines. Second, it's nice to have the dedicated Launch button for tables that use one, and this placement looks natural. You won't actually find any real tables that have both the plunger and the Launch button, so it's artificial in that strict sense, but it looks perfectly normal even so, because plenty of real machines have some sort of extra control below the plunger (e.g., an Extra Ball button).

Other plunger/Launch button layouts

The traditional plunger location shown above doesn't work for everyone, because it can create a space conflict with the TV if you want to position the TV at the very front of the cabinet. Before you drill anything, take a moment to consider if you'd prefer some other setup. Here are the most common options:
  • Include only the plunger, with no Launch button. Some people prefer a more authentic setup with just the plunger. This an easy modification: just don't drill the hole for the Launch button.
  • Invert the arrangement so that the Launch button goes on top and the plunger goes below. Some people use this arrangement to make room for the TV to fit closer to the front of the cab. To make this change, use the inverted plan below.
  • Include only the plunger, but lower it to get it out of the way of the TV, so that the TV can be mounted closer to the front of the cab. To implement this, use the inverted plan below, and skip drilling the hole for the Launch button.
  • Include only the Launch button, with no plunger. To do this, use the inverted plan below, but don't cut the plunger opening.
For more advice on choosing among these options, see Plunger.

Inverted plunger/Launch button

Here's the inverted layout, with the plunger below the Launch button. This places the Launch button at the exact position used on real machines that use this control (which also happens to be the standard plunger position, not surprisingly), so it'll look authentic as far as that goes; of course, the addition of the plunger below the button isn't to be found on any real machines.
Inverted arrangement with the Launch button on top and the plunger on the bottom.
Note that the spacing between the plunger and Launch button is a tiny bit tighter with the inverted layout than with the normal layout (by about an eight of an inch). This is due to space constraints. The plunger can't safely be moved much lower, because the exterior side of the plunger housing will conflict with the front right leg if you do. If you really need to move the plunger even lower than shown (to make room for the TV, for example), you might be able to eke out a few extra 16ths of an inch, but it might be an uncomfortably tight fit. Measure your actual parts carefully before making changes.

Other cutouts

I don't recommend any other controls or ports in the front wall, since this is the most conspicuous part of the machine other than the playfield area, it's already pretty busy with just the standard controls. However, there are a few extra items that some people add here:
  • Volume controls
  • Night mode switch
  • USB/keyboard/mouse ports
I'd personally avoid the front panel for all of these and place them on the bottom or back of the cab instead, where they'll be less visible.
For volume controls, I'd recommend using doubled-up flipper buttons instead of a separate knob (see my PinVol page for an explanation). But if you really want a separate knob, and you don't want to have to reach under the machine to operate it, one way to make it inconspicuous is to install it in the coin door, by drilling a hole for the knob stem.

Rear wall

After the insane complexity of the front wall, it'll be a welcome relief that its posterior counterpart is rather simple.
Rear wall, viewed from the interior side.
The fan openings are designed to accommodate 120mm PC case fans, mounted just behind the openings (on the inside of the cab) and oriented to blow air out the back. These aren't authentic to the original WPC design (for the original layout, see the diagram below). The WPC machines had smaller, passive vents. Most virtual cab builders want to include fans to actively blow air through the cabinet for cooling, which the larger openings accommodate.
The power inlet opening is there to pass the machine's main power cord through the back, for plugging into a wall outlet. This is the same as the original WPC equipment, which has a C14 power inlet (the same type of power cord connector used on most desktop computers) behind the opening.
The size and placement of the fan openings and power inlet are merely suggestions. Customize them as you see fit. Take care that anything you install on the back wall doesn't get in the way of the playfield TV, but that usually isn't a problem, since the back end of the TV is usually well forward of the back wall. The leg notches and floor dado should be implemented as shown, since those do have to align with other parts.
Attention: Reproduction cabinet builders: The circular fan openings shown in the diagram above aren't authentic to the original WPC cabinet design. The Williams cabinets of the 1980s and 90s did have vents in the same area, but they were smaller and were purely passive (no fans). The original layout is shown below.
Original rear wall design used on the real machines, with passive cooling vents instead of fan openings, viewed from the interior side. This is the layout of the Williams cabinets of the 1980s and 1990s. Virtual cab builders usually replace the vent slots with larger circular openings that can accommodate PC case fans, to provide active cooling. Virtual cabs tend to need active cooling in the main cabinet because they typically house a TV and a PC motherboard, both of which can generate a lot of heat.
Most people use the same joinery style for the rear wall as for the front wall, but that's not required. I think a mitered join (such as a mitered rabbet or lock miter) is nice here, since it yields seamless corners, but that isn't as important here as in the front, since the back wall isn't as visible. A simpler join that produces visible seams, such as a rabbet or even a butt join, can be perfectly adequate aesthetically.
Top view of rear section, showing the joinery shapes at the rear corners. This uses the mitered rabbet as described in the side walls section earlier.
The leg bolt notches work exactly like on the front and side panels. Use the same measurements as the rear leg notches on the side panels, since those need to align with the ones on the back wall when the cabinet is assembled. See the side wall section above for details.
The floor dado is a routed groove. The floor will slip into this groove when you assemble the cabinet. This is the same as the floor dados on all of the other pieces: route a ¾" wide groove, ⅜" deep (about half the thickness of the plywood), in a straight line ¼" from the bottom of the wall. See the side wall section above for a diagram.

Power inlet

The hole near the lower right of the back wall plan is for the main AC power inlet. On the real machines, this is a 2½" diameter hole positioned as shown. There's nothing special about this location for a virtual cab; move it and/or resize it as needed for your own power supply setup. If you're not sure how you're going to set up the main power supply, you can just follow the generic plan, since it's pretty versatile; the opening is large enough that you could just feed a power strip's cord or an extension cord through it, and it could also accommodate a C14 inlet mounted in the opening. You can drill a hole of this size with a hole saw bit, or using a hand router with a circle jig.

Fan openings

The fan holes in our back wall plan represent a deviation from the real WPC cabinet design, to meet the special needs of the virtual cab. Real pinball machines don't need much cooling for the main cabinet, so the WPC cabs just have a pair of small passive vents at the back. Virtual cabs, in contrast, tend to need active cooling with fans, since the main cab has a big TV and (in most cases) a PC motherboard.
Our plans provide two openings in the rear wall designed for PC case fans. The idea is that you place an exhaust fan (blowing air out of the cabinet) on the inside of each opening. The cabinet floor (which we'll get to next) has another similar opening for an intake fan. This arrangement is designed to work with the natural air flow from the tilt of the monitor: the tilt makes the monitor higher at the back, so warm air will tend to flow towards the back of the cabinet as it rises. The exhaust fans at the back will help remove the hot air and pull cooler outside air into the cabinet from the floor vent.
The holes shown in the diagram are for 120mm fans (about 4¾" inches diameter). This is a common size for PC case fans, but other sizes are available; some people like to super-size their fans because larger tends to be quieter. Resize the openings for your fans as needed.
There's nothing magical about our placement of the fan openings, so move them as needed. I recommend keeping them relatively high up on the wall to take advantage of the natural flow of rising warm air. The point is to remove the hottest air from the cabinet, and that will tend to move towards the upper portion of the space.
For more on cooling, see Cooling Fans.

Other rear wall cutouts

Here are some other optional items that you might want to consider, as long as you're drilling holes in this piece. There's no standard placement for any of these, so use whatever location is convenient for your setup.
  • Ethernet port. Wired network ports can come in handy even if you're planning to install a Wi-Fi card or powerline Ethernet. The rear of the cabinet adjacent to the power inlet is an excellent place for this. Keystone jacks are useful here. See "External I/O plugs" in Installing the PC.
  • USB ports. It's also good to have some external USB ports, and the back of the cab makes a convenient place for a couple of these. As with Ethernet, you can use Keystone jacks. If you're installing a Keystone jack plate for Ethernet anyway, you can make it a 3-gang or 4-gang plate and populate it with a couple of USB ports while you're at it.
  • Keyboard/mouse ports (these are usually just more USB ports). I prefer the floor of the cab near the front, since that's where you'll actually want to use the keyboard and mouse, but the back of the cab will do if you just want a single cluster of ports.
  • Openings to pass wires for light strips on the back of the cab (see Undercab Lighting)

Back rails

The real WPC cabinets have a pair of wood rails on the back, as illustrated below. Each rail has a pair of 1" hard plastic furniture slider pads attached, one at each end. These are designed to let you stand the machine on its back, with the backbox folded. The machine is more compact in this configuration, which can be helpful for moving, shipping, and storage.
These rails are optional. If you want to include them, cut the two strips at the size shown. On the WPC machines, the ends are beveled at about 30°.
Shipping configuration: legs removed, backbox folded down, placed on back. The machine can be strapped to a pallet and boxed or plastic-wrapped. This is good for freight shipping because it has relatively small footprint and it's easy to move with a pallet jack.

Floor

Our plan for the floor of the cab makes some concessions to the special needs of the virtual cab, so its cutouts aren't quite identical to the normal WPC floor design. In particular, we moved the subwoofer from roughly the middle to closer to the rear of the cab, and we added an opening near the front for a PC case fan to actively draw outside air into the cabinet, to supplement the fans at the back that blow hot air out. The power button cutout is also slightly wider than on the WPC machines (1-3/8" in this plan vs. 1-1/8" in the originals), to accommodate an arcade-style pushbutton.
Main cabinet floor, viewed from above.
The joinery for this piece is as simple as can be. Simply cut the edges square. The edges fit into the dados (grooves) in the four walls.
The "cashbox fence" isn't a cutout - it simply marks the location of a short wall installed here on the real machines, mostly to hold the cashbox in place. (The cashbox is a plastic box that sits under the coin slots to collect the booty. It comes in a standard size for Williams machines; you can buy one from a pinball vendor.) If you're not planning to use the standard type of cashbox, you can omit the fence, which will leave more open space for PC parts. However, you'll certainly need some sort of container to collect coins, if you're using them; you don't want loose metal discs rolling around your electronics-packed cab interior. The standard cashbox is a convenient solution. But it's also awfully large. On my own cab, I improvised a much more compact coin box using a plastic food container.
If you want to install the fence, it's 3" tall by ¾" thick. Cut the length to match the inside cabinet width. Mount it at the position shown (or whatever position is right for your cashbox, if you use something custom). This isn't a structural element, so it doesn't have to be very strong; you can fasten it with glue and/or nails. Note: the distance shown (11⅛") is from the front of the floor piece, which recesses into the dado in the front wall by about ⅜". If you install this after assembling the rest of the cab, it goes 10¾" from the inside front wall.
The subwoofer opening is shown at the size used in the WPC machines, but the position is further back than in the real machines, where it's closer to the middle (22-1/4" from the back, to be precise). The virtual plan moves it back to create more contiguous floor space for the PC motherboard. I don't think it'll affect the acoustics much (if at all) if you want to move it further back still, for an even bigger stretch of open space.
You should consider changing the diameter of the subwoofer cutout to match the speaker you select. The 5-3/8" diameter cutout is based on the 6" speakers used in the WPC machines. Those are small by modern standards; automotive subwoofers are in the 8"-and-up range. If you do use a larger speaker, it'll sound better if the opening is roughly the same size as the speaker aperture.
The large fan opening towards the front isn't part of the original WPC design. It's a virtual cabinet add-on for our greater cooling needs. This is meant to be an intake fan, with a PC case fan mounted on the interior surface and oriented so that it blows air into the cab. This helps draw in cool air from the bottom to replace hot air being blown out by the fans at the back. See Cooling Fans for more on this subject.
As with the fan openings in the back wall, the position and size shown are only suggestions, and there's nothing special about the exact placement shown, other than that it's generally close to the front of the cabinet to promote front-to-back air flow. The opening is sized for a common 120mm PC case fan. Some people think it's better to use two intakes to match the two vents in the back, so you could add a mirror-image opening on the opposite side (near the power button). But I wouldn't go too overboard on adding fan vents, as they eat into the space available for the PC components and other items, plus too many cutouts will weaken the floor.
The two small (1½" diameter) holes near the back corners are from the the original WPC design, and they're for ventilation. These are redundant in our design with the added opening for the PC intake fan, but I'd keep them anyway for freer air flow. They don't take up much floor space.
The power button opening is shown at the standard position for real machines, which works equally well in a virtual cabinet. The cutout in our plan is slightly wider than in the original WPC design (1-3/8" vs. 1-1/8"), to accommodate more types of buttons. The real machines use a "hard" on/off switch here that controls the AC power to the main transformer, so turning it off is basically the same as unplugging the machine from the wall. On a virtual cab, we usually want a "soft" power button instead, since we're working with a Windows PC, and Windows doesn't like abrupt power loss. Windows wants the power to remain on throughout the shutdown process, so a soft power control is needed. You just need a pushbutton that's wired to the "power button" connector on the PC motherboard. I use one of the common SuzoHapp rectangular arcade-style pushbuttons. This type of switch can be mounted as illustrated below, which recesses it nicely into the opening.
Installing a SuzoHapp rectangular pushbutton (part #D54-0004-5x) in the power button opening. Cut a small piece of plywood (about 2" x 3") to serve as the mounting plate. Drill holes as shown. Mount the button on the plate, then insert the button into the cutout. Attach the mounting plate to the cab floor with a couple of small wood screws.

Cab floor materials

The real WPC machines had particle board floors. I'm usually all for faithful replication of the originals, but this is a detail that I only see as a negative. I'm sure the only reason they used particle board is that it cut a few dollars off the cost. Plywood is lighter and stronger, so I'd stick with that. The problem with particle board is that it tends to sag over time, especially in a big unsupported horizontal span like this. That's been known to happen with older real machines, and I suspect it might be even more likely in a virtual cab, because we tend to install more things on the floor.

Customizing cutouts to accommodate the PC

Before finalizing your floor cutouts, you might want to figure out where you're going to place the PC components, so that you can customize the cutouts to better suit the PC. Some particular things to consider:
  • If you're going to install the PC in a full case (such as a desktop case or a mid-tower case), you might need to move the subwoofer opening further back to make room.
  • The PC needs good air flow for cooling. The air intake openings should be positioned so that they're close to the PC, and so that they'll be unobstructed. If you're installing the PC in a full case, you should figure out where the case's air intake will end up, and place a floor opening at the same spot, so that the case can draw in outside air directly.
See Installing the PC for more on planning the placement of the PC components.

Other floor cutouts

Here are some ideas for other cutouts you might want to make in the cab floor, as long as you're working on this piece. These aren't things you'll find in the real machines, and there's no particular standard place to put them in a virtual cab, but you can consider making provisions for them if they look useful for your build.
  • Keyboard and mouse ports (typically USB). The floor is a good place for ports for input devices that you might want to connect for doing administrative work on the PC, since it's out of sight but within easy reach. I'd pick an area near a front corner, perhaps opposite the power button. Keystone jacks work well for this. See "External I/O plugs" in Installing the PC.
  • Openings for undercab light wiring. If you're going to install light strips on the bottom of the cab for ambient lighting, you'll need a small hole somewhere in the floor for the wiring. A 1" diameter hole somewhere along one of the edges is pretty flexible for this purpose. See Undercab Lighting.
  • Volume buttons or knob. Some people like to put dedicated volume controls somewhere on the cab, and the bottom (somewhere near the front) is a popular choice because it's out of sight but easily reachable. You can use a volume dial here if your amplifier uses one, or an up/down rocker switch. I installed a rocker switch for this purpose on my own cab, wired through the keyboard encoder to send the Volume Up and Volume Down keyboard commands to Windows. On a new build, I'd probably dispense with the extra switch, and use "shifted" flipper buttons in combination with PinVol.

  • Other hidden controls, such as an audio mute button or a "night mode" switch (to silence noisier devices for late night use).
The bottom of the cabinet is a good place for controls that you want to keep hidden but accessible. There's an even better place for controls that you want to be restricted, not merely hidden: inside the coin door. Controls located there will not only be out of sight during normal play, but won't even be accessible to ordinary users who don't have the key, preventing kids or guests from messing with anything you don't want messed with. It's the same reason the real machines locate the operator menu buttons on the inside of the coin door. See Coin Door.

Cashbox fence

Cashbox fence; attaches to the cabinet floor just behind the cashbox area.
This is a short wall on the floor of the cabinet that delineates the space at the front of the machine where the cashbox goes. On the real machines, it makes a little cubby hole for the cash box and keeps it from sliding around, so that it stays positioned properly under the coin mechanisms.
I don't think most virtual cab builders bother to include a standard cashbox, since the standard model takes up a lot of space that you might prefer to use for PC components and other electronics. You'll probably want to skip the fence if you don't use a cashbox. If you do use the standard type of cashbox, though, the fence is worth including, since it holds the box in place.
Cashbox fence. The metal tab sticking up is the "cashbox lock bracket", which is attached to the fence, and fits through a slot in the cashbox lid. This is designed to hold a padlock for higher security.
Cashbox lock bracket (Williams/Bally part 01-10030 or 1A-3493-1).
While you're cutting the piece for the fence, also cut two triangular pieces that we'll use to attach the fence to the side walls on the cabinet. Slice a 2x2 strip in half diagonally (at a 45° angle) lengthwise, then cut two pieces, each 3" long. See the illustration above. Note that a nominal "2x2" actually measures 1½" on each side.
The original machines have a metal bracket in the middle, called the cashbox lock bracket (part number 01-10030 or 1A-3493-1), which can be used with a padlock to secure the cashbox. You probably won't feel the need for such strong anti-theft measures on a home-use machine, but if you want to include the bracket anyway for the sake of completeness, attach the bracket to the fence as illustrated below. Do this before installing the fence in the cabinet, since it'll be hard to drill the holes after it's in place.
Cashbox lock bracket. Center the bracket left to right, and make it flush with the bottom of the fence. Attach with two #8 x 7/8" machine screws mated with #8 T-nuts, or with #8 wood screws.
The original WPC machines use two #8 x 7/8" machine screws and #8 T-nuts to secure the bracket; drill 7/32" holes for this setup, using the bracket as a template for the drill locations, and pound in the T-nuts on the back side of the fence. If you want to keep things simpler, use #6 or #8 wood screws instead of the machine screws and T-nuts. That won't be as strong, but it doesn't have to be built like a bank vault for home use.

Rear shelf

Rear shelf. The top piece is the flat part of the shelf, viewed from above. This should be the same width as the outside width of your cabinet. The bottom piece is the front lip, which attaches below the bottom front edge of the top piece. This should be the same width as the inside width of your cabinet.
How the two shelf pieces fit together. The seam is usually hidden in the finished product, because the rear glass channel (a plastic trim piece that holds the playfield glass) covers roughly the top inch of the front face.
Routing detail. This view shows the bottom side of the shelf. Route out ¾" wide channels on the left, back, and right sides; this should match the thickness of the plywood used for your main cabinet walls. The depth of the channels should be half the thickness of the shelf, so ⅜" if you're using standard ¾" plywood.
How the shelf fits into the main cabinet.
This pair of pieces forms the shelf at the back of the cabinet where the backbox rests. The large opening is for passing cables between the backbox and main body; these match up with corresponding openings in the backbox.
Adjust the width to match your cabinet if you're using a wide-body or custom width. The center opening and bolt holes should be left at the same size (assuming you're using a standard backbox), and should remain centered left-to-right.
The 7/16" holes on either side of the opening are for bolts that secure the backbox in the upright position. Install a ⅜"-16 T-nut on the bottom side of each bolt hole. (T-nuts are threaded bolt sockets, permanently installed in a wood piece. Insert the barrel into the hole as shown and pound it in to secure it.)
These bolts are an important safety measure, by the way. Don't ignore them. You might think that the latch that conventionally goes on the back of the backbox is enough to secure it. Well, the real pinball machine operator manuals always have a big flashing red warning about that latch, saying that its only purpose is to hold the backbox up while you're screwing in the bolts. The bolts are what really hold the backbox up. The latch is a huge safety hazard in that it gives you a false sense of security; the backbox is so heavy that it'll easily rip that latch clean off at the first opportunity. The bolts will truly secure the backbox when properly installed.
The center opening is based on the design in the real machines, which use it to pass through a couple of big cable bundles. This setup works well in most virtual cabs as well, but there's at least one common situation where a larger opening is required: an oversized backbox monitor that needs to recess partially into the cabinet. In this case, expand the opening as needed.
If you customize the cutout shape, remember to make the same changes in the cutouts in the backbox floor. For alignment, use the back edge as the reference point, because the backbox's back wall will be flush with the cabinet's back wall when the backbox is installed and placed upright. For left-to-right alignment, use the center point as the reference; the backbox is wider than the shelf, but it'll be centered horizontally when installed, so the center points will line up.

Leg bolt spacers

One last detail. We need some spacers for the brackets used to fasten the legs.
The material required for the leg spacers is a 2x2 wood strip. Select a soft wood such as pine, since that will be less likely to split. Note that what they call a "2x2" at the hardware store is actually 1½" on a side. These typically come in lengths of 6' to 8'.
Cut four 6" lengths of the 2x2. Then slice them in half diagonally (at a 45° angle), lengthwise, to form the triangular wedge shape.
Drill two ½" diameter holes for the leg bolts as shown below. You can also just use your brackets as drilling templates. Drill through the diagonal face (the widest face), on the centerline, square through that face towards the opposite corner.
Drill starting on the diagonal (widest) side, square into that face. The hole should come out on through the opposite corner.
One hole will be near the center (vertically) of the wood piece, and the other will be near the edge. Make four identical copies of this piece.

Backbox

The backbox is (happily) a whole lot simpler than the main cabinet. It doesn't have as many cutouts, and we don't have to get as fancy with the corner joins. The top and bottom surfaces are typically out of view, so we can use joins that leave seams, by hiding the seams on the top and bottom edges where they won't be seen. All of the joins for the backbox can be accomplished with straight router bits.
The backbox is mostly built from the same ¾" plywood used in the main cabinet. There's one exception, though: the back wall is made from ½" plywood. The original WPC backboxes had ½" thick back walls, so we're sticking to the same plan to keep the interior dimensions the same.
If you want to substitute ¾" plywood for the back wall, it's fairly easy. You just have to adjust the routed grooves in the other walls where the back wall joins to accommodate the thicker panel. We'll give you a reminder about that when we get there.
Exploded view of backbox
Corner joins, viewed from the front. This type of join leaves a seam along one face, but we orient the joins to place the seams along the top and bottom , which are normally out of view.

Translite and DMD guides

The backbox requires some simple rectangular wood strips that acts as guides to hold the translite and speaker/DMD panels in place.
QuantityMaterialDimensions
2½" plywood4¾" x ¾"
2½" plywood15" x ¾"
1¾" plywood27⅛" x ¾"
2¾" plywood12⅜" x 1"
1¾" reducer molding or nominal 1x2 or 2x2 stock cut to a similar shape (see diagram below) 27⅛" length
The plywood pieces aren't visible to players, so don't worry about making the edges look pretty. They're all hidden behind the backglass or speaker panel when the machine is assembled.
The "reducer molding" shape is a more challenging trim piece that requires an angled cut. And this one is visible to players - in fact, its whole purpose is cosmetic - so you'll want to make it look nice.
One way to make the molding piece is to start with a nominal 1x2 strip or 2x2, and cut it lengthwise so that it has this approximate cross-section:
Note that a nominal 1x2 is actually ¾" by 1½", so chopping this profile out of a 1x2 just requires a single diagonal cut. The same goes if you start with a 2x2.
The diagram above is based on the molding used in the original Williams machines, but you don't have to reproduce the shape perfectly, because this piece is purely cosmetic. It's just there to hide the channel that holds the top of the backglass in place, to make the area look nicely finished. The only important thing is to give it a pleasing tapered shape.
In the diagram above, we show rounded corners, because that's what the trim on the real machines looks like. The rounded corners aren't critical; they're just to make it look more finished. You can just round out the corners a bit by sanding if you like. If you want to get fancy, you can round them out with a suitable router bit.
To make the diagonal cut with a table saw, set the blade at a 25.5° angle to the vertical, and feed the 1x2 or 2x2 stock in length-wise:
An alternative to cutting this shape yourself is to buy a pre-cut wood molding in roughly the same shape. There's a common type of floor trim called a 3/4" reducer molding that has roughly this same shape and size. A 3/4" reducer molding will typically be a bit deeper than the profile we want, since it'll usually have a lip that sticks out from one side. But it still might be easier to trim off that extra bit than to cut the whole shape yourself.
Once you have a strip in that shape, cut it to a length of 27⅛".

Translite lock plate preparation

If you're planning to install a translite lock plate, there's some preparation you can do at this stage that will make installing the lock easier and more secure when you get there. If you don't know what the translite lock plate is, you can learn about it in the "Translite lock" section in Cabinet Hardware. Briefly, it's a keyed lock that you can install at the inside top of the backbox to secure the translite. For a home machine, the security function isn't important, but you might want to include the lock anyway if you're a stickler for realism, since it's there on all of the real machines going back at least to the 1980s.
The translite lock is installed in the front translite guide (described in the section above), which is part of the ceiling of the backbox. The front guide has a gap of about 2 inches in the middle, specifically for the lock.
On the real machines, they install the lock plate with #8-32 security Torx machine screws (the Torx variation with tamper-resistant heads). The important thing to note here is that they're machine screws, not wood screws. Machine screws won't self-tap in wood; they need to be fastened with nuts. If you look at the arrangement pictured above, you can see that there's no way to install ordinary hex nuts by hand with this setup, because you'd have to get behind the wood trim somehow - and it's going to be glued in place by the time you're ready to install the screws. So the question is: how do you install a nut in a place you can't reach? The answer is a T-nut. A T-nut is threaded like a hex nut, but it's permanently installed in the wood rather than being screwed on by hand. They're specifically for this type of situation where you need to pre-install a nut someplace you won't be able to reach later.
So, if you want it to install it the professional way, the required preparation is to pre-install T-nuts in the 12⅜" x 1" trim pieces:
  • Drill a 7/32" hole, 1/2" from one end, centered across the width
  • Route a 3/4" recess on the same center, 1/8" deep
  • Insert a #8-32 x 1/4" T-nut from the recess side
  • Pound it in flush into the recess
All of this prep work is optional, at two levels. First, it's completely unnecessary if you're not going to install the translite lock. Second, even if you're going to install the lock, there's a simpler alternative: throw out the wacky Torx machine screws that come with the lock plate kit, and use ordinary wood screws instead. Wood screws will happily self-tap straight into the trim, without any other fasteners. So why would anyone (even the pros) bother with the T-nuts? In a word, security. Apart from the tamper-resistance of the security Torx screws, the T-nuts add a lot of strength. It's easy to pry out wood screws; it's almost impossible to pry machine screws out of T-nuts, short of ripping out the whole wood trim piece.

Extra routing for translite lock

For a good fit, there's a little extra routing you need to do for the translite lock.
In the 27⅛" x ¾" x ¾" piece, route a 2" wide notch in the center of one side, to ⅜" depth.
This is necessary to leave room for the lock tab when it's in the "locked" position. The tab is slightly wider than the slot, so it needs this extra room on the other side.

Backbox sides

Backbox left and right sides, shown from the interior side to detail the routed grooves for the joins. These are mirror images of one another. Note that the rear groove's width should equal the thickness of your back wall plywood. Our plans assume you're using ½" plywood for the back wall, so the groove is shown at ½" width.
3D view of the routed grooves in the side walls, to clarify the geometry.
The routing at the back edge assumes you're using ½" plywood for the back wall. If you're using a different thickness, simply increase the width of the groove to match the thickness of your back wall.

Backbox top

The top of the backbox has a few special features:
  • The front edge should be cut at a 7° angle to match the slope of the front edges of the side walls.
  • The side edges are routed on the top side in a rabbet cut, to fit the rabbet grooves in the side walls.
  • The back edge is routed on the bottom side in another rabbet cut, to fit the back wall.
  • A 1/2" wide, 3/8" deep groove runs across the width of the bottom side of the piece. This matches the plane where the translite fits. The translite doesn't actually sit in this space most of the time, but this groove provides a little extra room to lift the translite into when inserting and removing it. You can omit this if you're not using a standard translite.
  • A 2" wide rectangular depression is routed in the middle of the translite groove, on the bottom side of the piece, to accommodate the translite lock. Center this side to side, and refer to the diagram below for the dimensions. This is only needed to make room for the translite lock, so you can omit it if you're not using a lock.
Backbox top piece (roof)
To match the slope of the front sides, the front edge of the top piece should be cut at a 7° angle. This is an edge-on view from the left side.
3D view of top piece, viewed from top front, to show routing detail on the top side. The grooves at the wide are ⅜" deep and ⅜" wide, all the way to the outer edges.
Top piece, bottom side, viewed from the back, to show routing detail on the bottom side.
If you're planning to install any "toppers" (decorations on top of the backbox, such as a rotating beacon, fan, bell, or flashers; see Backbox Toppers), consider pre-drilling any openings in the roof that will be needed for mounting hardware or wiring.

Backbox floor

Backbox floor
To match the slope of the front walls, cut the front edge at a 7° angle. This is an edge-on view from the left side.
3D view of backbox floor, viewed from back side, to show routing detail. The groove at back is ⅜" deep and ½" wide, flush with the back edge. The ½" width should match the plywood thickness of the back wall.
Backbox floor, bottom side, to show routing detail.
Above: Cutouts in floor of backbox. The rectangular cutout is for passing cables between the backbox and cabinet. The 1"-diameter holes on either side of the cable cutout are for safety bolts that lock the backbox in the upright position. The ¼"-diameter holes along the outer edges (three on each side) are for the WPC-style hinge brackets that attach the backbox to the main cabinet. The hinge bolt positions shown are for a standard-width main cabinet - they need to be adjusted for a wide-body or custom-width cabinet (see below).
Cable cutout: The rectangular center cutout is meant to match the corresponding cutout in the "shelf" at back of the main cabinet. If you're customizing the shape of the cutout, remember to make the same changes in both places. To figure the alignment between the two parts, use the back edge as the reference point in both places. When the backbox is installed and placed upright, its back wall will be flush with the back wall of the main cabinet. For left-to-right alignment, use the center point as the reference: the backbox is wider than the shelf, but it will be centered side-to-side when installed, so the center points will line up.
Lock bolts: The 1"-diameter holes on either side of the center cutout are for locking bolts. These should be aligned on the same centers as the corresponding ½" holes in the main cabinet shelf. If you had to move those to accommodate a custom center cutout, move these holes to match. Note that the shelf holes are ½" diameter, whereas the corresponding backbox are 1" diameter. As with the center cutout, the reference point to use for alignment is the centerpoint of the back edge, because that will line up on the shelf and backbox.
Hinge bolts: The ¼" diameter holes near the outer edges (three on either side) are for carriage bolts that attach the WPC-style hinges to the backbox. Drill these only if you're using the WPC-style hinges.
Important! The positions shown are for a standard-width main cabinet. If you're using a wide-body or custom-width cabinet, or a custom backbox width, you'll need to refigure the positions. Use this formula:
Inset = (Backbox Width - Cabinet Width - 2⅜") ÷ 2
Plug in the outside widths of the backbox and cabinet (as they will be when assembled). The result is the inset of the bolt holes from the left and right edges of the floor, so simply substitute this for the measurement shown in our diagram.
If you don't want to take chances on getting the measurements perfect before-hand, you can wait to drill these holes until you've assembled your cabinet and backbox, at which point you can set it up and use the hinges themselves as a drilling template to mark the proper positions. This is getting a little ahead of ourselves, but here's the procedure:
  • Make sure the shelf is in place in the cabinet, if you haven't already installed it. No need to glue it yet; just set it in place.
  • Attach the hinges to the main cabinet using their pivot bolts. They'll rotate freely, so be careful not to let them scratch anything.
  • Put the backbox in position. Center it left-to-right, and align the back wall of the backbox so that it's flush with the back wall of the main cabinet. The front of the shelf will stick out slightly further than the front of the backbox; that's normal. Have an assistant hold it up so that it doesn't fall over from this precarious position - it's heavy enough to be dangerous!
  • Rotate the hinges up into position where they'll attach to the backbox. Make sure the contact area is flush with the bottom of the backbox. Mark bolt hole positions.
  • Take down the backbox and drill at the marked positions.

Backbox back wall

The back wall of the backbox on the real machines is typically 1/2" plywood. It's a simple rectangular piece, with some holes for passive cooling.
Backbox back wall. The holes near the top are for passive ventilation. Note that the back wall uses ½" plywood rather than the ¾" plywood used for the other walls.

Backbox ventilation

The original WPC backboxes used passive ventilation, via seven 1½"-diameter holes along the top of the back wall. ("Passive" meaning that they didn't use fans to circulate air; they relied on natural air flow driven by hot air expanding and rising.)
Some virtual cab builders add fans to the backbox for extra cooling. If you want to add active cooling, I'd remove the passive vent holes and replace them with one or two larger circular openings for 120mm PC case fans, similarly placed near the top of the back wall. You could also add some intake vents at the bottom, although I don't think that's necessary, as air will be drawn in from the main cabinet through the openings in the backbox floor.
Is active cooling required? From my own experience, the answer seems to be no. My cab uses passive ventilation (the same design shown in the diagrams here), and I haven't had any obvious heating problems. That doesn't necessarily rule out longer-term problems, but at least nothing gets catastrophically hot. If you want a more analytical answer, you can do a rough calculation comparing the heat generated by the electronics in a real WPC pinball machine's backbox to the heat generated by a TV in a virtual cab backbox (see Cooling Fans). That calculation comes out about even between the two scenarios, which strengthens the case that passive ventilation is adequate.
On the other hand, there's little downside to adding a fan or two, other than the space they take up and the added noise (which should be minimal if you use a large fan). If you do plan to add a fan, just take into account the space required for the TV, DMD, replay knocker, and any other backbox devices you plan on installing.

Backbox back door

Some virtual cab builders make the back of the backbox into a door rather than a fixed wall.
The plan I'm presenting here uses a fixed back wall, following the original Williams design. On the real machines, most of the main control electronics are mounted on this wall - the CPU board, sound board, power supply board, etc. To access these parts for service, the operator simply removes the translite and accesses the interior from the front side.
The complication for a virtual cab is that we fill most of the backbox with a TV. Some cab builders mount the TV in such a way that it can't be easily removed, in which case you won't be able to access anything behind the TV through the translite side. That's where a back door comes in handy.
I don't have an alternative set of plans to offer using the back door approach, so if you want to go that route, you'll have to improvise something. Other people have built such schemes into their cabs, so you might be able to find ideas by checking build threads on the forums.
I personally prefer the fixed back wall, instead of a door. The main reason is that it makes the backbox a lot stronger if the back is a solid, fixed panel. I also don't like the idea of using a permanent mounting for any of the TVs, since doing so makes it very difficult to repair or upgrade the machine later. I prefer to install all of the TVs (and other major components) in such a way that you can remove them non-destructively when necessary. In the case of the backbox TV, I favor mounting it so that it can be removed through the front of the backbox, preferably without having to disassemble anything. That removes any need for a back door. It also makes it easy to replace the TV, if that should ever become desirable or necessary.
See Backbox TV Mounting for some ideas about how to mount the TV so that it can be removed.

Toppers

If you're installing some kind of "topper" (a decoration on top of the backbox, such as a beacon, fan, bell, or flashers: see Backbox Toppers), consider pre-drilling any openings needed for the mounting hardware and wiring.

How to assemble the cabinet

Before you glue everything together more or less irrevocably, it's a good sanity check to do a "dry fit" of the pieces (fitting them together without any glue or nails) to check that everything is the right size and aligns as expected. Check for any dados that are too tight, and use sandpaper or a file to expand them slightly as needed. Check the alignment of the rabbet joins.
Have a good quality wood glue on hand. This will be used at all of the joints. Optionally, you can also use finish nails (perhaps ¾" #18 brads) along the seams, spaced a few inches apart. Nails will add some strength and will serve to hold the joints in place while the glue dries, but the trade-off is that they create a certain amount of risk of splitting wood around the edges. I used nails for my own build, but I don't think they're really necessary. If you're using the joins we suggested (dadoes at the floor seams, and either the mitered rabbet or double rabbet joins at the corners), I think glue alone will be plenty strong.
Another good thing to have on hand is an assistant! The job is easier with two people.
It should be fairly obvious how the pieces fit together, but here's a suggested assembly order.

Pre-assemble the shelf

Install a #6-32 x ⅜ on the bottom side of each bolt hole. (These are there to mate with safety bolts screwed in through the matching holes in the backbox, to secure the backbox in the upright position.)
Glue together the two pieces that make up the shelf as illustrated below. The front edge of the lip should be flush with the front edge of the top piece.
Set the assembled shelf aside for the glue to dry, so that it'll be set when we're ready to install it in the cab later on.

Main cabinet

On to the main cabinet! Start by joining the floor to one of the side walls. Put glue along the inside of the dado (groove) at the bottom of the side wall as illustrated below. Don't use an excess of glue - you just want a single continuous bead down the center of the groove. Insert the floor into the groove. Make sure the front and rear edges are properly aligned and flush, and ensure that it's pressed down all the way into the dado.
Beware that this arrangement is precarious! The floor piece will want to tip over; the dado isn't strong enough by itself to hold it upright. Keep the floor piece supported so that gravity doesn't stress the joint. It's good to have an assistant to hold things in this position until you get to the next piece.
Next, add the back wall. Put glue along the dado and edge of the back wall that we're about to join, as shown below. Again, use continuous bead of glue. Put the back wall piece in place. As before, make sure that the edges are aligned properly and that the floor is pressed all the way into the dado in the back wall.
Now do the same thing with the front wall.
Add the remaining side panel.

Leg brackets

The next step is to install the leg brackets. The brackets will be permanently installed in the cabinet, so this is a one-time step that you won't have to repeat when you want to attach or remove the legs.
The procedure here assumes you're using the standard brackets used on newer machines, Williams/Bally part 01-11400-1. These brackets have integrated threading for the bolts, so no additional nuts or other fasteners are needed - you just screw the bolts into the brackets.
You'll need four of these brackets. The matching bolts are ⅜"-16, in 2½" or 2¾" lengths. Note that you'll probably want to buy the bolts from a pinball vendor rather than use generic hardware store bolts, for cosmetic reasons: the ones made for pinball machines have nice shiny finishes and rounded heads that look nicer than generic galvanized hex-head bolts. You'll need eight bolts (two per leg). No washers or nuts are needed, as the brackets are threaded and serve as the fasteners.
The recommended brackets have their own threading for the bolts, which lets you attach and detach the legs purely from the exterior of the cabinet. In other words, there's no need to reach inside the cabinet with a wrench to turn a nut or other fastener, since no other fasteners are needed - the bolts screw directly into the threaded holes in the brackets. That's important because it's difficult to reach into the interior corners (especially with a wrench) once all of the equipment inside is installed. So the threaded brackets make things much easier in the long run, but they require some extra work for the initial installation, since you have to align them and fasten them inside the cabinet. That's what the procedure below is intended to accomplish.
All four legs are interchangeable - there's no such thing as a "front leg" or a "back leg" or a "right leg" or a "left leg". You should simply have four identical parts for the legs. The same is true of the metal leg brackets.
Before we begin, it's worth noting how the positioning of the leg bolts relative to the floor of the cabinet affects how the brackets and spacers are installed. The bolt holes are higher up on the wall in front, lower in back, to give the cabinet a slight forward tilt when it's set up. (The legs themselves are all the same length, so we get the tilt by mounting the legs at different heights.) Because of this asymmetry, we can flip the brackets upside down in front to keep them lower on the wall.
We'll start with a dry fit (no glue) to make sure everything fits, before we finalize the install. The bolt holes tend to be tight, which is good in that you don't want a lot of play or wobble when the legs are attached. But the bolt holes in the wood can be so tight initially that the leg bolts just won't fit. We need to make sure that the bolts will fit properly.
With the cabinet on its side, place the leg in position, and insert the bolts through the leg holes and into the cabinet. If the fit is too tight to get them through by hand, use a round file to ream out the holes enough to get them to fit.
The point of using the legs for this step is just to make sure that the spacing of the bolt holes in the legs matches the spacing in the cabinet. We're not actually attaching the legs permanently yet; we're only attaching the brackets at this point. The legs can be easily attached and detached at any time once the brackets are installed.
Once the bolts fit comfortably, slip the triangular wood space piece over the bolts.
Now attach the metal leg bolt bracket. Screw in the bolts to make sure everything still fits.
If anything is wrong with the fit, go back and use a round file to open up the holes in the cabinet walls and/or the spacers as needed. (Obviously, don't attempt to modify the legs themselves or the metal bolt bracket! We consider those to be the source of truth here - they're the reference points we're trying to match with the wood parts.)
Once you're satisfied with the fit, take the bracket off and remove the spacer. We're now ready to install this all permanently.
Keep the legs and bolts in place, since we still want them there as the reference point for final alignment.
Apply glue to the sides of the spacer that face the cabinet walls. (Those are the narrower sides. Don't glue the wider side that faces the bracket.) Use a thin layer of glue covering the whole face. Avoid the area around the bolt holes to avoid too much glue oozing in there.
Put the spacer back in place. Press it against the cabinet walls to attach the glue.
Reattach the bracket and screw the bolts into it. Screw them in all the way this time so that the leg is firmly attached. Don't over-tighten.
Use #8 x 5/8" wood screws to attach the metal bracket to the cabinet walls and to the spacer. The standard plates have holes for three screws on each side and two more in the middle to attach to the spacer. Don't leave out any screws; we want the bracket attachment to be very sturdy, so we want to distribute the load over as many screws as possible. Tighten the screws but be careful not to over-tighten and strip the wood.
Note: some people recommend #10 x 3/4" screws for greater strength. I've seen this advice in the context of people fixing split corners on their newer Stern machines, which reportedly use cheaper brackets that don't provide any corner bracing. I suspect that upgrading to #10 screws is a bit of overkill when using the Williams-style brackets, but I can't see it doing any harm. However, do be sure to check that the longer screws don't poke all the way through the plywood - you don't want a dimple or a sharp point sticking out through your artwork. The bracket is thick enough that this shouldn't be a problem, but I'd still check to make sure. If it looks like it's going to be close, you can add a washer.
Use #8 x 5/8" wood screws to fasten the leg bracket to the cabinet and spacer at the locations shown (arrows).
Once the wood screws are all in place, unscrew the main leg bolts and remove the leg.
Repeat this process for each corner until all four leg brackets are attached.

Cashbox fence

If you decided to include the fence that delineates the cashbox area, this is a good time to install it. Flip the cabinet upright for this step.
Figure the desired position for the fence. Assuming you're using the standard type of cashbox, the front surface of the fence should be 10¾" back from the inside of the front cabinet wall. If you have your cashbox on hand, you can try placing it to ensure a good fit - there should be about 1/2" of play front-to-back.
Without using any glue yet, set the fence in place at the desired position.
Apply glue to the two square sides of the 3"-tall triangular pieces that you cut along with the fence. Making sure to keep the fence at the desired position, press the triangular pieces into place on the rear side of the fence at each side, to fasten the wall to the two sides of the cab.

Back rails

If you want to include the back rails, attach them to the back of the cabinet, oriented vertically, near the edges. The exact positioning isn't particularly important, as long as the rails form a stable base for standing the machine on its back, so make any adjustments needed to keep clear of your fan vents and other openings in the back wall.
Attach these to the back with glue and finish nails (1¼" #18 brads should work). Nail down the centerline, with a nail every 4" or so.
If desired, affix 1" hard plastic furniture slider pads near the ends.

Shelf

At this point, you can install the shelf that you assembled back at the start of the build process. We saved this for last (in particular, until after the leg brackets were in place), because the shelf gets in the way when you're trying to work around the back wall. For exactly this reason, you might want actually want to skip the shelf for now, and come back to it later, after you've had a chance to install the internal items that you may plan to attach to the back wall:
  • Fans
  • Power inlet
  • Power strips
  • Ethernet port
  • USB ports
If you want to hold off installing the shelf for now, you can just set it aside and make a mental note to come back here when you're ready.
If you haven't already done so, install ⅜"-16 T-nuts in the holes on either side of the central rectangular opening, on the bottom side of the board. These mate with the wing bolts that are meant to be attached through matching holes in the floor of backbox. The bolts are an important safety measure to secure the backbox in the upright position while deployed.
Once you are ready to install the shelf, start by flipping the cabinet upright.
Run glue around the edges of the shelf where it joins the main cabinet (as shown below), and set it in place.
If the top of the shelf sticks out at all from the side or back walls, use a power sander to remove excess material until it's flush with the adjoining wall.

Backbox

Assembling the backbox is much like assembling the main cabinet. Start with the top and one of the side walls. Apply a bead of glue to the groove on the side piece, then fit the top piece into the groove.
Attach the floor.
Add the remaining side wall.
The back wall should now fit into the grooves along the back edges of all four walls. Apply glue around the grooves, and put the back wall into place. It should fit so that it's flush with the edges of the walls.
The back should be flush with the back edges of the adjoining walls when installed.
In addition to the glue, you can add some finish nails to strengthen the back wall. Use small finish nails, such as 1" #18 brads. Drive them in from the back of the back wall, around the perimeter, set in about 3/16" from the edges. Space them every few inches; four or five nails on each side should be sufficient.

Corner bracing

The original WPC backboxes had steel braces at the corners to strengthen the joints. The glued corner joints are actually pretty sturdy all by themselves, if you construct them using the rabbeted design described above, but apparently Williams deemed it necessary to add some heavy reinforcement. I'm sure that came out of long experience with commercial operators who banged the machines up with rough handling and then complained when they broke.
In my opinion, you shouldn't need any corner braces for a machine in home use. The glued corners should be plenty strong. But if you'd like to reproduce the original construction faithfully, or you just don't trust the glue joints, here are the details for the Williams design. The Williams part number for the braces is #01-9167, and they're fastened to the backbox walls with ¼"-20 x 1-¼" carriage bolts (black finish, 4320-01123-20B) and ¼"-20 flange nuts (4420-01141-00). You'll need four of the braces and sixteen each of the carriage bolts and flange nuts. Place one brace at each corner, more or less all the way back against the back wall, and use the holes in the brace as a drilling template to drill holes for the carriage bolts. Insert the carriage bolts with the heads on the outside, and fasten with the flange nuts on the inside.
WPC backbox brace, Williams part #01-9167, installed at the upper corner. The real WPC-era machines used one bracket like this at each corner. If you want to go this route, use the brace as a drilling template to drill ¼" holes for the bolts, and fasten the brackets with ¼"-20 x 1¼" carriage bolts (on the outside) mated with ¼"-20 flange nuts (on the inside).
The Williams corner bracing is about as strong as you can get. You'd have to rip the wood apart before those bolts would come out. The downside is the bolts are visible on the outside of the backbox. (Not too visible, though; the WPC machines use black bolts that tend to disappear into the artwork unless you're looking closely.)
How the carriage bolts look on the outside. They have smooth rounded heads (with no screwdriver slots), and come in silver and black finishes.
If you don't care about using the exact original parts, but you still want some kind of corner reinforcement, you might consider using generic steel 1" corner braces instead. You can buy these at any hardware store. Use ¾"-long wood screws to attach them, in a size that fits the holes in the corner braces you buy (#6 screws will usually work). Use two or three braces per corner. Keep them within 5" of the back wall, so that they won't be visible when the translite is in place. This setup won't be as strong as the Williams brackets and carriage bolts, but it provides some reinforcement, and it doesn't require any externally visible fasteners.
Alternative reinforcement using generic hardware-store corner braces, fastened with wood screws. Be sure to keep the braces behind the translite plane (5" from the back wall), so that they're not visible.

Translite/DMD guides

The WPC backbox has some little wood blocks along the walls that act as guides for the translite and DMD/speaker panel. These might or might not be interesting to you for your virtual cab, because a virtual backbox is a little different from a real one. Specifically, our backbox uses a TV in place of the normal translite, and in some cases a single TV replaces both the translite and DMD panel.
But it's not a simple matter of TV or translite. You might actually still want something similar to a translite, to mask out the bezel around the perimeter of the TV. There are two common ways to handle this:
  • Create a custom wood cover for the TV area, with a cutout for the TV.
  • Use a glass or plexiglass translate in front of the TV. Optionally, you can use paint of decals around the perimeter of the plexi to mask out the dead space beyond the edges of the TV display.
Both serve the same function, of hiding the TV's bezel so that you only see the screen, but I very much prefer the second option. The first option calls way too much attention to the virtual-ness of the cab. The second makes it look like a real pinball machine.
(There's a third, less common option. Some people route grooves into the side of the backbox exactly deep enough to contain the TV's bezels. This requires an extremely thin bezel, and requires that you use a custom backbox size chosen to perfectly match the TV, so it's not compatible with the standard plans.)
If you're planning to use a custom wood cover instead of a translite, you can skip this section, as your custom cover won't need the guides that hold the conventional parts in place.
Before proceeding with installing these, there are some cases where some of the guides should not be installed:
  • If you're not using a standard speaker/DMD panel, don't install the lower guides (the ones at the bottom of the side walls) until you've worked out whether or not you need them. These are designed for the pre-WPC-95 style of speaker panel only, and might not work if you're using a home-brew design of your own.
  • If you're using a WPC-95 speaker panel - the type that's made out of a single piece of molded black plastic - don't install the lower guides. The lower guides are only for the older pre-WPC-95 speaker panel. If you're using a standard panel type but you're not sure whether it's WPC-95 or pre-, consult Speaker/DMD Panel for help.
  • If you haven't finalized your backbox TV install plan yet, don't install the upper side wall guides. Those get in the way of some TV installation methods. See Backbox TV Mounting for more.
Assuming that you're using the standard translite and the early 1990s style of speaker/DMD panel, here's a cutaway view showing the placement of the guides on the sides of the cabinet. Note that the right side wall isn't shown in this view, but (as you would probably expect) has the same two guide pieces shown on the left wall, at the same positions in mirror image.
Guides for the translite and speaker/DMD panel on side walls. The distances shown are to the inside surfaces of the back wall and floor in the assembled backbox. Note that some backbox TV installation designs work better without the 15" upper pieces, so you might want to defer installing these until you've finalized your backbox TV plan. Also note that the lower pieces are only used for the "original" style of speaker/DMD panel, not the WPC-95 molded plastic type.
The top piece is 15" x ¾" x ½", and the bottom is 4¾" x ¾" x ½". Orient them so that the ¾"-wide face is against the side wall. Both pieces run parallel to the rear wall.
There's nothing sophisticated about the installation of these on the real machines - they're just glued and nailed. You should do the same thing. Apply a little glue on the back of each piece and nail it into place with finish nails (I'd suggest 1" #18 brads). Use one nail about every 4" down the length of each strip, centered in the strip.
Here are the guides on the inside of the backbox "roof":
Cutaway side view of the top guides. The pieces labeled "A", "B", and "C" are detailed below.
Note how the "A" and "B" pieces align with the translite groove in the ceiling.
Note that piece "A" should be installed with the notch facing the ceiling of the cab.
Top guides, viewed from below.
All three pieces run parallel to the rear wall.
  • "A" is 27⅛" x ¾" x ¾". It should fill roughly the full width of the backbox interior; simply center it left-to-right relative to any leftover space. Install it with the routed notch for the translite lock (if you included that) facing up, towards the ceiling of the cab.
  • "B" (quantity 2) are each 12⅜" x 1" x ¾". Leave a ½" gap front-to-back between these pieces and the "A" piece, and leave a 2¼" gap left-to-right between the two "A" pieces.

    Important! If you installed T-nuts for the translite lock plate, see below.

  • "C" is the wedge-shaped trim piece we described earlier. Orient it as illustrated in the side cutaway view above. Install it abutting the "B" pieces, without any gap.
Aligning the T-nuts in the "B" pieces: If you installed the T-nuts for the translite lock plate as described earlier, you should make sure they're correctly aligned for your lock plate when you install the "B" pieces. Use this procedure:
  • Lay out the pieces at the install location as described above, but don't glue anything yet.
  • Orient the pieces so that the T-nuts are on the side that will be glued to the ceiling of the backbox.
  • Grab your lock plate and its Torx screws. You don't need to assemble the rest of the parts yet, but it's also okay if you've already done so.
  • Put the lock into position. Make any adjustments to the positions of the "B" pieces to match up the screw holes in the lock plate with the pre-drilled holes in the "B" pieces.
  • Fasten the lock plate by screwing in and tightening the screws.
  • With the lock plate installed, glue and nail the trim pieces into position.
  • Remove the lock plate.
This will ensure that the "B" pieces end up perfectly aligned with the lock plate. If you install the pieces separately, very slight variations in the measurements could leave the T-nuts so misaligned that you wouldn't be able to fasten the screws.