The axles in the official BSA Pinewood Derby Kit are FAR from perfect. They will have many imperfections that will need to be addressed before you can make a competitive car. This article will address each imperfection.
Straightness. I have handled, sorted, and tested thousands of Pinewood Derby axles. You will rarely find a factory Pinewood Derby axle that is straight. How can you tell? Take your axles and chuck them in a drill press approximately 1/2″ from the head. Now spin the axle at a high RPM. Notice the wobble? Yep, the axle is not straight. Now chuck it closer to the head. The wobble may be less or even disappear.
To eliminate the wobble, the axle will need to be straightened. You can straight the axle properly by purchasing an axle press. (The axle press will also give make the axle true and round.)
I have read many pack rules that do not allow “bent” axles. Well, unbeknownst to them, most axles come already bent (unintentionally) straight from the factory.
These rules are placed to offer a level playing field for the builder. These rules were placed to prevent the negative and positive camber of the rear wheels and steer axle. (And the placement of a high wheel in some instances.)
A better translation of the intended rule should read, “axles may not be bent and will be visually inspected for creases that are the result of intentional bending.
Crimp marks. The crimp marks should always be removed. A small file, patience, and sandpaper will achieve this. You should use wet sandpaper at various grits ranging from 500-2000.
When using the file, be careful not to remove too much mass from the axle as to reduce the overall diameter. Also, you should avoid pressing down with too much pressure. It is easy to bend the axles during the de-burring and sanding process.
When wet sanding, give extra attention to the spots where the axle will make contact with the wheel. You want these spots to be as smooth as possible.
Axle Head. The axle head on factory axles are not squared (90°) to the shaft. The axle press addresses this problem while also providing a nice taper which will give the axle less contact with the plastic wheel, thus reducing friction. This is a huge added benefit for positive results.
Finally, the proper spelling of AXLE in the pinewood derby context is A-X-L-E. Not AXEL.
Though they are pronounced the same, the meaning is different based on the spelling.
AXLE- A rod or rounded shaft that connects one or two wheels.
AXEL- An axel is the name of a figure skating move like the “triple axel” which was named after the Norwegian figure skater Axel Paulsen.