Axle Mounting Accuracy = Greater Speed!
For top speed, axle slots or holes must be absolutely square to the car body and parallel to each other. Unfortunately, the only way to achieve this level of accuracy has been with a drill press - a power tool that is not available to most car builders. But that has all changed. Now anyone can create accurate axle holes with only a hand drill or Pin Vise and two clamps.
Introducing the Pro-Body Jig, a precision-machined, aluminum and steel device that will improve the speed of your pinewood derby car through accurate axle mounting. In addition, the Pro-Body Jig will slightly lower the center of gravity of the car(1), resulting in a more stable car.
The Pro-Body Jig is equipped with #44 guide holes for use on BSA, PineCar, and other kits with nail type axles. A #44 bit is included.
To use the Pro-Body Jig, follow the instructions included with the kit, or the instructions given below. Click on any of the small pictures to view a larger picture.
- Two clamps are required to use the jig (not included).
- A 3/32 hex key is required to adjust the tool (not included).
- The Pro-Body Jig cannot be used to drill pilot holes in axle slots. Check your local rules before drilling axle holes.
(1)The Pro-Body Jig drills holes centered at 5/32 (.156) inch off the bottom of the block. The Pro-Body Tool drills holes centered at .081.
"Many people have asked for a 'Dual Pro-Body Tool'. Now it is a reality. The guide bar is precision ground to provide a high degree of alignment accuracy between the front and back drilling guides."
- Test fit the tool on the bottom of the block with the four "ears" positioned on the sides of the block. If the tool will not fit onto the block, use coarse grit sandpaper to reduce the width of the block until the tool fits snuggly. If the tool is loose, the fit can be tightened by placing a piece of paper, folded as needed, between the left or right ears of the jig and the block
Mark the Block
- Measure and mark the desired position of the new axle holes on one side of the block. Extend the mark from the bottom of the block to the top of the block using a square (or measure and mark near the bottom of the block and near the top of the block, and then join the line with a pencil and ruler). Holes for extended wheelbases are typically positioned 11/16 inch from each end of the block.
Adjust the Jig
- Adjust the Pro Body Jig to the desired wheel base; a 3/32 inch hex key is used to loosen and tighten the set screws. The wheel base adjustment can be verified by measuring between the index marks on the jig
Clamp, and Drill
- Position the tool on the bottom of the block with the four ears on the sides of the block. Align the index marks on the jig with the lines corresponding to the axle hole positions on the block.
- Clamp the jig in place will two clamps, one on each of the drilling guides (note that the clamps shown in the photos are larger than necessary).
- Hold the block firmly, position the drill bit in the hole, and drill 3/4 inch into the block.
- Without releasing the clamp drill the other holes.
- If a raised hole is desired, drill only one of the front holes (either one) and proceed to step 9.
- Transfer the line on the side of the block to the bottom of the block.
- Position the jig on the desired side of the block, and align the index mark on one of the drilling guides with the line on the bottom of the block. Make sure that the third hole on the guide is positioned near the bottom of the block.
- Clamp the jig in place and drill the raised hole.