First revision for a flywheel cage to shoot Nerf Rival foam balls. This is a work in progress and very high performance should not be expected. The Fusion 360 files are provided so you can adjust motor mounts, flywheel size, and ball diameters.

I took apart an old Nerf Hail-Fire and used its 1.5V - 3V motors along with the very nice driver board. The motors have a 2mm diameter shaft. The shaft is 7mm long with the top 5mm being knurled. The provided flywheels have a 5mm deep hole in them for a precise fit. The flywheels have a ball gap of ca. 19mm which provides a small amount of compression for the 22mm balls.

My PLA prints so far have all been low quality (0.2 layer height, 0.4 wall thickness, 10% infill) and that seems to be working out okay.

Instructions: print one cage and two flywheels. After removing the supports make sure the center channel is smooth, sand if necessary. Squeeze the motors all the way into their housings. If they do not fit, use a Dremel sanding drum to widen the mounting holes just a little bit. Make sure motors spin in opposite directions!
With motors inserted, put the assembly on a sturdy surface, then push flywheel on the shaft. The top of the shaft should be flush with the top of the flywheel. The easiest way to achieve this is using a coin or other flat piece to push the flywheel into place.

Sindoh 3DWOX

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