Nema motor shaft coupler / fitting

thingiverse

This is a simple design for the Nema 17 motor (it may also work for the Nema 23). I was building the "Simple filament extruder puller by james_III" when I found some rubber wheels with a 7mm diameter hole, but my Nema 17 motor shaft had a 5mm diameter so I needed something to make the shaft fit tightly on the rubber wheel hole. On the files attached you'll find an .STL ready to print, and I also included the 123D design source files in case you want to modify the fitting for use on a wheel or any other project with a bigger diameter. Simply use the "pull" function to make the tube thicker (it can't be made thinner, the walls are thin enough already). You'll find two versions of the fitting: V1 and V2. V1: This drawing is supposed to represent a perfect fit, with a 5mm internal diameter hole and a 4.6mm distance from the flat point of the Nema shaft, and a 7mm external diameter. V2: This drawing was slightly adjusted to actually fit the shaft. When you're printing, certain plastics tend to shrink when cooling, which caused the V1 files not to fit my motor shaft. So I increased the size of the tube a bit and V2 fits quite well.