DIY Pinewood Derby Axles Archives - Pinewood Derby Speed Axles

August 2, 2018

DIY Axles

How we make speed axles

We will discuss how we made our axles prior to utilizing CNC cutting and proprietary nail straightening. This is how you can do it at home with very little tooling and still get great results. Substitute a drill clamped horizontal for a lathe. Using a vertical drill press can be utilized, but it is very hard to give proper pressure and control.

Making BSA axles into speed axles is an art and process. You have to have very specialized tooling to do it correctly as well as efficiently. This is the method that we followed and then tweaked to your liking. It’s a very good start, although the visuals could have been a little better. We didn’t own a go pro at the time.

To start off you are going to need 3x the amount of axles that you need. If you are making one car, then we suggest a dozen axles. If you don’t want to purchase 2 extra set of wheels and axles, then you can visit this store to get them by the dozens.

The reason being is that you only want to attempt to fix the ones that are the straightest. It seems that the axles just might be purposely bent…

Tools Needed

File–the finer the cut the better. The key is to remove the burrs and crimps without reducing the diameter of the axle. We used this file for the longest time. I suggest a barratte file #00 cut.

barrette file

Sandpaper-wet-400 grit through the sky is the limit…. we like 2000 for dry lube. 60,000 grit for oil
Derby Worx Pro Axle Press–a must for straightening an axle
Metal “bucking” bar to support your sandpaper while sanding. Just anything that is hard and flat about 1/2″ in width. We prefer this method over the sawing the paper back and forth across the axle.
Baster of some sort to add water.
Bowl to catch water from wet sanding
Clean strip of cloth material to clean each stage of sanding. YES each stage needs its own cloth. You can NOT share with another stage. NOT MICROFIBER! Microfiber will grip a turning axle and cause cause harm to you. They just have too much surface area. You can even use a thick cotton string to do the trick.
Your going to need a hammer
Proper safety equipment
Some sort of drill, drill press, or lathe. NO DREMEL!!!!! Spins / removed material too aggressively.
Metal sealant/wax of some sort to keep your new polish job from rusting. Do your research to find the DIY. Most like some kind of jewelry rouge or wax based car polish. We have our own special sealant and it’s not one of those.

August 2, 2018August 2, 2018

Tuning board can’t tell you if your wheel camber is stable at high speeds

When you bent your axles did you gap your axle prior to bending? If not, it is quite possible your bend will begin somewhere inside your wheel hub which will cause all sorts of chattering and aligning issues. No one addresses this important step. And you will not be able to see if it is an issue until your car is at it top speed. Unfortunately, a 6 foot tuning board can not show you this. Only a full size level track or a treadmill can.

It is near impossible to tune 3 bent axles without a treadmill in a fair amount of time. You’ll drive yourself crazy. Find you a treadmill. Take it to 10 MPH and watch what is happening.

If you have to have 4 wheels touching- Set it up as a 3 wheel car at first, then watch this video.

With a 2.5 degree bend you have basically 30 degrees of rotation or less to get it to ride on the axle heads. It’s just a really sharp bend. It way faster than 1.5 degrees, but it is going to take a little time to get it right for the first time rail riders. If you want to bend 4 axles, I like doing 3x 2.5 degree bends and 1x 1.5 degree bend This gives you the option of having a 2.5 steer for super fast setup, or you can use standard 1.5 steer. Which ever axle you don’t use, simply place on high side with the bend in the UP direction to maintain a high wheel.

You can bypass the rear bent axles with drilled axle holes at 3 degree camber with the fancy new drill station jigs.

August 2, 2018August 2, 2018

Are you doing your Pinewood Derby Axles Correctly?

Can you see what you are really doing to your axles?

Be careful! A recent fellow derby dad sent us a car to evaluate. He could not understand why he did not place as well as previous years. His COG for weight was appropriate at about 7/8″ in front of rear wheel. His car was mostly aerodynamic with no obvious drag designs.

The car was a 3 wheel rider with a steering axle used for tuning. Upon quick observation, I noticed one of the axles had rough edges. I figured that was the main cause of his less than expected performance. So I took off the three wheels and this is what we found. As you can see there is damage on each axle. The tooling used to install/tune each axle permanently damaged the axle by providing rough almost burr like edges that rob your car of speed needed. Every little bit of damage matters when you are talking about .001 seconds from first to second place.

This derby dad was totally surprised when I sent him my findings. He could not believe what damage he had done to his axles.

Recommendations to remedy this common pinewood derby problem

#1 First is to make sure that the bend of your axle happens outside of the area where the wheel spins. A bend in this vital area of your axle causes the wheel to bind as you can imagine the wheel is no longer rolling on a straight plain. Its path around the axle is an elliptical rotation. With each pass of the wheel, the diameter of the inner wheel hub is being wore larger which is making the car drive different with every race. This car will never run the same race twice.

#2 Notice the burrs around the edges. This is caused by improper tooling. Probably a regular set of needle nose pliers were used to adjust. Solution: Pinewood Axle Tuning Pliers

#3 What can also be seen here is that the graphite flake is too large and not soft enough as it is still on the axle without being ground down into the layers necessary to build the friction-less surface. It does matter what graphite you use. The stuff at the hobby store, might not be your best bet.

We highly suggest our graphite which is seen below