You may find that your Gottlieb
Wedgehead backbox door is missing. This page is about creating your own
wedgehead backbox door from plywood. I outline the steps below to show
you how to build this backbox door. You can buy a metal door from The
Pinball Resource for around $35 plus shipping, but this is a cheaper
solution and may offer you the excuse to buy a new rotary saw and drill.
If the door wasn't 25" wide you could maybe get a couple of doors made
from a 4 foot wide sheet of plywood, but not so for this 25" door. If
you are lucky, maybe you can find some plywood "waste" at your local
lumber yard that is 36" wide which will accommodate one door's width.
But, determine how many doors you'd like to make and choose the plywood
that will accommodate the width and length (25" wide by 24-1/2" high).
Also choose the grade of plywood that meets your needs. Cheaper plywood
shows up with knots and glue areas, but if this doesn't bother you, then
that will be the cheapest way to go. I don't like the look of Oriented
Strand Board (OSB) so I wouldn't recommend using it.
Plywood - 1/2" thick. Note that the original door is closer to
5/8" thick, but 1/2" thick plywood works well. Some folks even use a
1/4" thick piece of plywood but to me that's a little on the skimpy
side. Look at the plywood selection and decide how "rough" you want
the plywood to look. The cheapest plywood will be more likely to
splinter and have knots that show. This is in the back of the
backbox so it isn't like it will always be visible.
Lockset - a 3/4" diameter hole will be drilled for the backbox
door lock which is typically either 7/8" long or 1-1/8" long. You
should be able to measure on your backbox from where the surface of
your new door will be to where the latch will flip up to secure the
door. You can order a lockset or two or three from The Pinball
Resource (Steve Young).
- Pencil - for drawing lines on the plywood in
order to cut out your backbox door.
- Measuring tape - pretty hard without one although
you could use the measurement indicators on your framing square if
it's large enough.
- Saw - your choice for the type of power saw you
want to use, but it would be easier than using a hand saw and
doesn't really require a table saw if you can saw in a straight
line. Any rotary saw should work fine such as a Craftsman, Rigid,
Black and Decker, etc. You could also use a Jig saw if that's all
you have but you might end up with a cut that swerves in and out.
- Drill - you will be using the drill to drill a
hole for the lock. To be even more precise, you could use a drill
press to get a perfectly perpendicular hole to the face of the door.
- Hole saw - either use a 3/4" hole saw or a
Forstner or spade hole cutter in your drill.
- Framing square - ensure the rectangle you will
cut out of a sheet of plywood is squared.
- Primer - you don't have to paint the wooden
backbox door if you don't want to since it will not be visible
unless you can easily see behind the game. If you want to paint the
backbox door, you'll need to prime it first.
- Paint - either a can of latex
or a spray can be used. Just be sure the primer you use will
work with the paint you choose. You can spray it using a spray can
of aluminum colored paint (or silver) if you want it to look close
to the color of a metal door.
Steps - refer to the
- Using your framing square, ensure you
start off with a piece of plywood that has squared edges. If not, then
use your framing square and pencil to draw straight lines and cut your
plywood with the rotary saw (I'll choose a rotary saw to do the sawing
but you can use whichever type of saw you want).
- Cut the plywood to 25" wide and 24-1/2"
high. Use a good saw blade so that splintering is minimized.
- Use your framing square on the corners to ensure the
door is square. It doesn't have to be perfect, but starting with a nice
squared piece of plywood makes measurements easier.
- Examine your plywood flipping the door over to examine
each side of the door and decide which end should be the end where the
lock hole will be drilled. If using a lower grade of plywood you
wouldn't want to drill the lock hole right in the middle or edge of a
knot. Whichever end you choose, it will become the "top" of the door
which I will reference later. Also on this step, decide which side of
the door you want to face outwards where it will be visible. No two
sides of the door are perfect, so pick the nicest looking side of the
door. This "finished" side will become the "face" of the door that will
be viewable by someone looking at the back of your backbox. The finished
side of the door is where you will draw your lines and make your saw and
- Measure in from
one corner on the top of the door and make a mark with your pencil at
12-1/2" on the plywood that represents the center line of the door which
is also the center line for the lock. Measure from the opposite corner
and see if it too is 12-1/2" to the line you marked (it should be, if
you cut the plywood correctly - 12-1/2" + 12-1/2" = 25" wide).
- Use your framing square on the top of the door at the
center line of the door (which is the center line for the hole) and draw
a line vertically downwards about 3" long. This will be used to locate
the center of the lock.
- Measure down 1-1/2" from the top of the
door at the center line for the hole and draw a horizontal line. You
have now identified the center of the hole for the lock. The place where
the vertical center line crosses the horizontal line is the point where
you will want to place the center of your hole saw/bit to drill the lock
- OK, we find ourselves with a rectangular door, we've
determined which end will be the top of the door, and we've located the
center of the lock hole. At this point we are through with the top of
the door (we'll drill the hole later).
- I'm assuming you cut a nice squared door, so with this
in mind, start with the left corner of the face of the bottom of the
door and measure in 2" and make a mark with your pencil. Using the
opposite corner of the face of the bottom of the door, measure in
towards the center of the door and draw another line at 2". If you use
your measuring tape, you can check the width between the two lines you
drew on the bottom of the door and they should read about 21" between
the two lines (25" - 2" - 2" = 21".
- By now, we've determined where the box will taper from
the top of the door to the bottom of the door. So now it's time to make
two more cuts with your rotary saw.
- Lay a flat straight piece of metal from the upper left
corner at the top of the door, down to the mark you made at the bottom
of the door that is 2" in from the left edge. Draw a line that will
represent the left edge of the door once the excess wood is removed. I
have different sizes of framing squares that can handle this distance
but if you don't', you can use a drywall cutter square or any other
straight metal to get a nice straight cut.
- Get out your rotary saw and start at the top left of
the front of the door and cut along the line's edge towards the bottom
of the straight line at the bottom of the door. This is the most stable
way you can cut the door using these techniques (as opposed to starting
at the bottom left of the door and cutting upwards to the top left of
the door). You get more of the saw's sole plate resting on the plywood
when cutting which offers you the chance to get a straighter line.
Remember that you want a good many tooth finishing blade in your saw to
reduce tear-out and splintering.
- Now we're on to the right side of the door. Draw a
similar line from the top right of the door down to the 2" mark you made
inwards from the lower right corner of the door.
- Use your rotary saw to cut along the line starting
from the bottom right of the door and cutting upwards to the corner of
the upper right part of the door.
- At this point we've completed cutting out the door
from the squared stock. The next thing to do is to cut the hole for the
- Place a spare piece of board behind the door right where you expect
the drill to pass through the plywood. A 1" X 3" piece of scrap wood
could be used OK. This "backing board" will be used to minimize the
splinters and tearout, just hold the door to the backing board securely
(or even clamped if you want to do it that way).
- Pressing down on the drill, use your hole cutting saw
or Forstner bit, or just a 3/4" flat spade bit and start drilling
through the plywood using at a medium to high speed. Slow down as you
get almost all the way through to minimize splintering but keep sawing
until you know you've gone through the door and are now drilling into
the backing board. Once through, turn your door over and look at the
hole from the backside of the door. It should look just fine. Some folks
will drill through half of the door and once the tip of the hole saw,
spade, or Forstner pushes through, they just flip the board over and
drill from the backside using the hole that was created when only just
punching through to the other side. It's up to as to which technique you
want to use.
- You can now lift up your door and see how well it fits
within your backbox. If it all looks good, you can choose to paint the
door or just leave it as it is. If you want to paint the door, don't
mount your lock just yet since you might get paint on it.
- If painting, prime both sides and edges of the door
with a latex primer. When that is dry, you can choose a can of latex
silver or aluminum colored paint and roll it on with a micro roller or
spray it on with a spray gun if you have one. You could also use a
primer that can be used with a spray can of paint and paint the door
with an aluminum or silver colored spray can. I kind of like the micro
roller and latex paint since it seems like I get a nice even coat of
paint that doesn't have flashing or a strange sheen caused by spray
- When dry, mount your lockset in place paying attention
to which way the key has to be pointing when it can be removed. You'll
want the key to be able to be removed when the "latch" is vertical and
keeping the door locked. If it feels too loose, you can just bend the
latch so that you get a little more tension when the door is locked.
Well, that's about it for this project. I've made 4 or
5 doors now using this technique and it seems to work pretty well. If
the edges are too ratty you can use a sander to smooth them off.
Accurate measurements and straight cutting are the main skills you will
need. Hope you find it interesting.
Graphics & Text © Steve Corley
pictures you see were created by Steve Corley unless otherwise
Unauthorized use is strictly prohibited