Pinewood Derby Roadster Shell

thingiverse

A shell for a pinewood derby car in the shape of a roadster, more or less following the look of the 1949 Snowberger-Offy Indianapolis 500 racecar. The shell will drop on top of a standard pinewood derby wood block, which only needs a small bit of sawing (see the instructions). March 29, 2014: Updated version 7 cleans up the exhaust area and adds four holes in the underside to accomodate standard pinewood derby cylindrical weights. April 12, 2014: Updated STL of the body is "roadster_body.stl" and includes support structures underneath. Use this version if you don't trust your slicer to generate proper support structures (I don't). The photographs are from this version. If you notice two notches along the side, they are for an exhaust pipe (STL forthcoming, probably in a few days). April 21, 2014: See also my derivative Thing #305925. Designed as a model/toy instead of a pinewood derby shell, it still has the same wheelbase and the body can be used interchangeably with the pinewood base described here. There are also some useful accessories like exhaust pipes. Print with plenty of support. See the photos for an example of removable support structures under the print. The featured photo is from sourlemonjr's beautifully finished make of the roadster, used with permission. Instructions This piece is both rounded and hollow on the bottom, and so needs to be printed with ample support material. Enough of the piece is in contact with the bed that it should not require a raft. The pinewood derby woodblock needs to be cut to fit (dimensions to be given, shortly; also, look at the wings3d source file, which contains a model of the wood base and wheels). STL files for the steering wheel and driver are included. The steering wheel is in three parts to make it more printable. I have not tried printing the driver, so I cannot (yet) vouch for how well it prints. Clearly it needs plenty of support. Wood block cuts: Start with an official pinewood derby wood block. First cut down to a height of 10mm. Then cut off the front, to within 9mm of the front axle cut, and the back, to within 9mm of the back axle cut. Then cut the sides in (or use a router) by 9mm on each side. Just like the front and back, the side cutouts start 9mm behind the front axle and extend to 9mm in front of the rear axle (measurements are to the axle cut edge, not to the centerline of the cut). The inside cuts don't have to be square. I have designed the shell to accomodate a curve on the inside corner, as you would get if you make the cut with a router, or use a drill at the inside corners. I have uploaded the STL file of the wood block so that you can see what it is supposed to look like.