Nema motor shaft coupler / fitting

thingiverse

This is a simple fitting/couping for the Nema 17 motor (don't know if it works for the Nema 23 as well). I was making the "Simple filament extruder puller by james_III" and found some rubber wheels that had a 7mm diameter hole, but my Nema 17 motor shaft had a 5mm diameter so I needed some sort of "tube" to make the shaft fit thight on the rubber wheel hole. On the files attached you will find an .STL ready to print, and I also included the 123D design source files in case you want to modify the fitting to be used on a wheel or any other project that has a bigger diameter. Just use the "pull" function to make the tube thicker (it can't be made thinner, the walls are thin enough already). You will find 2 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 to 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 are printing, certain plastics tend to shrink when cooling and that shrinking caused that the V1 of the files did not fit my motor shaft, so I increased the size of the tube a bit and V2 actually fit quite well.