Measuring the Bend Angle of Bent Axles

By and


Bent axles are used in Pinewood Derby Racing for a several reasons.
1. Aligning the front axle(s) to make the car run in exactly the right direction.
2. Aligning the rear axles to eliminate conflict between them and keep the rear wheels off the guide rail.
3. Encouraging the wheels to migrate toward the ends of the axle.
4. Causing the wheels to ride on an edge of the tread rather than on the full face of the tread.

Usually the bend is quite small and is difficult to measure. Often the bend is difficult to see without aid. This page includes a gage with which to measure the bend in an axle.


Display and print the gage image.
If you don't have the Adobe PDF Viewer, you can get it here: Download Adobe PDF Reader

Check the print to verify that the aspect ratio has been preserved. This is accomplished by measuring the dimensions of the rectangle at the bottom of the page. If it is not square, the aspect ratio has been lost and the printed angles will not be correct.

How to use the gage

1. Identify the side of the bent axle that will contact the wheel bore.
2. Compare that side of the bent axle to the various lines, looking for the sides to correspond on each side of the common point (apex). The apex of each angle is below the "B" on the gage.

Try several orientations of the nail until the maximum bend is noted. That is what you need to measure.
Don't try to get the nail bend point to lie on the apex ... the bend is not sharp enough. Instead look at the straight parts of the axle.
Page created: 12/2/2014
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