Is your little cub scout joining a pinewood derby? Making fast pinewood derby wheels can be quite tricky. However, if you can work well on the axles and the wheels, your pinewood cars will be one of the best and the fastest.
Here is how to make fast pinewood derby wheels.
- Prepare and purchase all needed materials. For this particular project, you will need hub tool, wheel mandrel, emery paper with grits of 220, 320, 400 and 600, flat needle file, plastic polish, powdered graphite, pipe cleaners at least 3 millimeters, 4 or more BSA wheels, hand drill and wheel shaver, OR and drill press with fine flat file and square block. There will be 4 levels of preparing your car for racing. First, you have to shape and polish the inner hub that connects with the body of the car. Second, you have to level and polish the outer wheel diameter. Third, you have to level and polish inside part of the wheel edge. And fourth, you have to polish the bore of the wheel.
- Test the wheel and the axle. You can do this by placing the wheel into a complete axle and turn it to see if the wheel spins freely. The wheels must rotate for more than 3 seconds without chattering. If it does not, work on another axle or dispose off the wheel to work on another. Get 4 good sets of axles and wheels by testing them together.
- Shape up the hub. Shape the wheel's inside hub – the one that goes in opposition to the car – using the hub tool with 220 grit emery paper. As soon as the hub is shaped, use another hub tool, which has finer emery grit paper and the paper towel with plastic polish in it to get rid of all scratches to give a silky finish. The coning reduces the hub’s friction in opposition to the car. However, follow the supplier's instructions to use a wheel shaver to mold the wheel's inner edge and outer diameter or else just build up the wheel into the mandrel then onto the drill press.
Smooth out the outer diameter of the wheel with a 90-degree slab as a point of reference in maintaining the large file parallel to the inner bore of the wheels. Since the wheel is made of plastic material, use only low pressure and slow speed on the file so the plastic will not melt. While the wheel is off round, the file will sound and feel like it is bouncing. But once it becomes perfectly round, it becomes smooth. The indicator that the wheels are already round is when the outside diameter of the wheel looks uniform.
- Make or mold the inner edge. Hold the needle file next to the inner edge to begin shaping it and getting rid of any irregularity. Improve the inside edge of the wheel toward the outside diameter once the inner edge is already smooth. In most tracks, the wheel’s edge will run in opposition to the center. Any irregularity can slow down the car. Again, when shaving the wheel, build up the wheel into the mandrel so the mandrel goes to the hand drill to fasten it to the table. Get rid of all scores from the outer diameter of the wheels to the inner edge using the 220-grit emery paper. However, when using a drill press, carry on using the right angle slab to keep the outside diameter corresponding to the bore of the wheel. Just be certain that you do not make a flat spot, or shrink the wheel, or make the edge raised.
- Work on the wheel bore. As of the mandrel, remove the wheel and place 3-4 inches piece of the pipe cleaner down the drill. Using a plastic polish, cover the pipe cleaner and cautiously put it in the bore of the wheel. Turn the drill on and for 30 seconds, buff up the bore and get rid of the pipe cleaner to change it with the second one, which is covered with powdered graphite.
In a paper towel, place the graphite and finalize the inner hub through buffing. Once all excess graphite is removed and polish, your wheel is now ready for use. So, what are you waiting for? Go and surprise your little Cub Scout with your carefully made pinewood derby wheels.