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
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
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
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
. 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
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
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.
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
- 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
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:
- 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.
- 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
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
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
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
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
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
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
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
The lockdown bar is the main challenge. Fortunately, there is a
source for custom-width lockdown bars:
. 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
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
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
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.
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
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
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
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
- 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.
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
. 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.
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
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
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.
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.
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
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
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
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
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.
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
5. Repeat step 3 with the second side piece to cut the 7-1/8" flat
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
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
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
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
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.
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.
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
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
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.
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
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
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
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:
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
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
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.
- 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
- 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
- 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
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
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
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.
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
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.
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
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
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.
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
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.
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
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
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
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
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
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
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
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"
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
the plunger" in Plunger
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.
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
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.
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
- 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
For volume controls, I'd recommend using doubled-up flipper buttons
instead of a separate knob (see my
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.
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 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
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
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.
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.
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
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.
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
- 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
- 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)
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.
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
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
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
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
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.
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
- 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; attaches to the cabinet floor just behind the
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
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. 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
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.
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.
|2||½" plywood||4¾" x ¾"|
|2||½" plywood||15" x ¾"|
|1||¾" plywood||27⅛" x ¾"|
|2||¾" plywood||12⅜" x 1"|
|1||¾" reducer molding or nominal 1x2 or 2x2 stock cut to a similar shape (see diagram below)
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
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
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
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"
- 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
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 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.
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
), consider pre-drilling any openings in the roof
that will be needed for mounting hardware or wiring.
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
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
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
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.
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
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.
If you're installing some kind of "topper" (a decoration on top of the
backbox, such as a beacon, fan, bell, or flashers: see
), 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
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.
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.
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
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
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
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
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
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
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
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.
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
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
If desired, affix 1" hard plastic furniture slider pads near the
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:
- 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
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
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.
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.
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
- Create a custom wood cover for the TV area, with a cutout for the
- 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
- 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.
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
- 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.