Pinewood Derby Car

This 3D-printed model race car meets a Pinewood Derby car's size and weight restrictions. This car, of course, is not made of wood and therefore isn't legal in a traditional Pinewood Derby. It might be a fun entry into an “Outlaw Class” race.

I modeled the body in Fusion 360 with “predrilled” holes for the standard Pinewood Derby “axles” (nails) and body cutouts to accommodate the standard wheels included in a Pinewood Derby kit. I used old wheels and nails from other Pinewood Derby cars I had around the house, but you can purchase the kit from a variety of places or even find 3D models of the wheels and axles online. (3D-printed wheels might work with a bit of sanding.)

Once the car is printed, the nails can be pushed into the holes for a snug friction fit.

I've included the GCODE file I used for your use or reference. In order to make the car weigh as close as possible to the 5-ounce limit, I used 10% gyroid infill for most of the body and then added a box modifier just forward of the rear axle with 100% infill. Feel free to experiment with different infill percentages throughout to achieve the desired outcome.

I sliced about 0.5 mm off the bottom of the model in the slicer to give it a flat base. The file out of Fusion 360 has some curvature on the bottom that wouldn't print well.

As I said, rules differ from race to race but almost all of them require you to use the wood block included with the kit and many require specific placement of the wheels on that block. This model doesn't meet either of those requirements. It's just for fun and to show kids what's possible with 3D modeling and 3D printing.