Creating Accurate Pinewood Derby Axle Slots

By Randy Davis
Most brands of pinewood derby kits come with slots on one side of the block into which the axles are pressed. These pre-made slots generally work well, but there are occasions when the car builder would like to cut new axle slots. These include when:
1. The existing slots are defective.
2. The builder wishes to change the wheelbase by cutting new slots on the opposite side of the block.
3. The builder wishes to build two cars from one block by cutting new slots on the opposite side of the block.
Previously, cutting new slots was a bit tricky. Usually, a hacksaw was equipped with two blades, and then the builder carefully cut new slots by following a pencil line. Obviously, errors were common: cutting a slanted line or cutting too deep were common issues.
But now, a new tool is available to solve these issues and greatly simplify the process of cutting new slots.
DerbyWorx recently introduced the Pro-Body Slotter. Similar to the Pro-Body Tool for drilling accurate axle holes, the Pro-Body Slotter is a cutting guide for cutting axle slots.

Figure 1 – Pro-Body Slotter
The tool fits over a standard pinewood derby block, and is held in place with a set screw (a clamp would interfere with sawing). Index marks on the tool are aligned with a pencil mark on the block which identifies the desired location of the new slot.

Figure 2 – Pro-Body Slotter Parts

Figure 3 – Pro-Body Slotter Parts
As mentioned before, two hacksaw blades are mounted on a hacksaw frame (one blade is mounted with the teeth forward and the other with the teeth reversed. The blades are then placed into the slot in the tool, and the cut is made.
After the first cut is complete, the tool is loosened, moved to the next slot position, reattached, and then the second cut is made.

Figure 4 – Pro-Body Slotter in Use
The index screw will leave two indents in the block, one per slot. These marks are filled with wood filler before sanding and painting. Note that the marks will be located behind the wheels, so they are not obvious.
Here are a few tips for using the Pro-Body Slotter.
1. Use the Pro-Body Slotter on the pinewood derby block before cutting or shaping the block.
2. When placing the tool onto the block, orient the set screw on the side of the block opposite the pencil marks.
3. Keep the set screw on the same side of the block for both cuts.
4. Use even, gentle forward and back sawing strokes.
5. Make sure to stop when the saw blades reach the bottom of the tool.
6. For an extended wheelbase, position the slots at 5/8 inch (actually I prefer 11/16 inch) from each end of the block.
7. After cutting the slots, use a Pro-Axle Guide to insert a spare axle into each slot position, then twist and pull it out with a pair of pliers.
8. When painting, either mask off the axle slots, insert a spare set of axles into the axle slots, or better yet, use a Paint Stand.(1)
Using the Pro-Body Slotter makes creating accurate axle slots a simple process. The Pro-Body Slotter is available from many on-line vendors including Maximum Velocity. You can find the tool Here.
(1) The Paint Stand is available from Maximum Velocity Here.
From Pinewood Derby Times Volume 14, Issue 2
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