First, you need a design for your wheel. Start with some quick sketches of what you might like, then get out a compass and ruler to proceed on to a more accurate drawing. I found that the thumb area is most important, so pay particular attention to this point! When designing the wheel, indent the spokes where your thumbs wrap around the wheel.Make a cardboard pattern so that you can actually grip it in your hands to get these dimensions correct. It's important to consider comfort. Remember, if you are an avid racer, long hours will be spent clenching the wheel. Comfortable grips are essential and they should make for maximum natural handling.
Constructing a wheel for a driving sim is not as difficult as you might think. I made mine by laminating together three pieces of wood. The core or spoke part of the wheel, made of 1/4" luan, is sandwiched between two layers of 1/2" birch plywood. The birch constitutes the grips and can easily be rasped or routed to shape the rough form. Afterwards, I added a block of laminated pieces of birch to the center of the core (the back side..where the steering shaft attaches but...more about that later). When shaped and sanded to the desired contours, I finished it off with several coats of black automobile primer, lightly sanding between coats. Buffing this with 0000 steel wool brought the wood to a nice lustre that was soft looking. If you've taken time to do this carefully, the wheel doesn't look a bit like wood at all. Everyone who saw mine thought that it was made from anything other than good ol' plywood. I loved it!
Next, you'll need to consider a hub for the back of the wheel. This is nothing more than a block of wood that spaces the wheel away from the dash and also provides you with a place to attach shifting paddles, if you so choose. This can simply be a square block, if you like. It depends upon what your plans call for or just how fancy you want to be. At any rate, glue it to the back of the wheel with furniture glue and clamp firmly (not too tight!) until the glue sets up. Drill a 1/2" hole for the steering shaft (straight! Preferably with a drillpress) and she's ready to paint.
Use a 1/2"x8" carriage bolt for the steering shaft locking it to the wheel with a nut and lockwasher. Attach the bearings to the shaft with nuts and lockwashers, spacing them aprox. 2" apart. Where the L-bracket is located is optional. It can be in between the two bearings as shown above, or at the end of the shaft nearer the potentiometer, it's up to you. U-clamps hold the shaft/bearing assembly to the base. An L-bracket holds the pot in place, but make sure that the shaft lines up to the center of the steering shaft. A small 1/2" plastic radio knob on the pot shaft will accommodate a piece of 1/2" PVC pipe in joining it to the steering shaft. Drill two small holes in the PVC pipe and tap them for set screws. This keeps the two shafts in sync and prevents any slippage. It will also make it easier to calibrate the pot later on.
Alternate Connecting Method
First, attach two nuts and a lockwasher to the end of the pot shaft that you've threaded with a 1/4 20 die. This will somewhat equalize the thicknesses of the pot shaft and the steering shaft. Actually, with the nuts attached, the pot shaft is still a little bit smaller than the steering shaft, but that's good, because it allows you to turn the pot shaft for calibrating. Using a piece of rubber hose (automobile type: vacuum, fuel, etc.), slip it onto the end of the steering shaft and tighten on a hoseclamp to secure it. Next, slip the other end of the hose onto the pot shaft , but don't tighten the clamp on this one until, you've calibrated the pot .
Wheel Centering Methods
A bungee cord (shown here in orange) is attached to an L-bracket and secured in place with a small metal clip that is bolted in place. Each end of the bungee is attached to a bracket or eyebolt on either side of the steering shaft. When the wheel is turned, the bungee will stretch (shown here in yellow). The bungees will return the wheel to the neutral or center position when released. You can adjust the tension on the wheel by simply tightening or loosening the bungee cord.
An alternative method is to drill a horiz. hole through the steering shaft, and insert a 1/4" bolt. File the end of the bolt, on both sides, and drill a hole through the tab that is created. This will give you a means to attach the bicycle chain. When the wheel turns, the spring stretches while the chain slightly wraps around the steering shaft. Releasing the wheel, returns the spring to its original position, and pulls the pin back to the center position. This method assures better control without any slippage.
Adding a spring to the other side helps to center the wheel better. I bought a 1.5 in. pulley from Sears Hardware Center that works great and it's easier than drilling through the steering shaft as shown above. The pulley is the type that you can attach to the shaft of an electrical motor. It has a half inch I.D. opening and a hexhead setscrew to secure it in place.
The dash can be made of any thickness of wood, but since it doesn't bear any stress or load, I prefer to use material 1/4" thick. It's easier to attach switches to this thickness because the shafts of most switches are only about 3/8" or so in length. However, you might want to edge the dash with thicker wood for support. I traced my dash on a piece of 1/2" plywood, cut it out, and then scribed a line 1" in from the edge all the way around it. Next, I cut out the center piece, which left me with a frame 1"x1/2" to mount the dash on. At any rate, at least glue a strip of wood along the bottom to give yourself a flange to mount it to the base. Lastly, brace the dash at each end with either metal or wood braces. Voila'!
You can get real fancy here, if you like! Maybe, vinyl material cemented to the dash would do it for you. This looks really nice. I did it to the first wheel that I made, and the results are very professional looking. "Crinkle" paint is another cool finish, but it's hard to find anymore. Whatever you use is okay. There are no rules that govern this area except to have fun. Go for it...be creative.