NEMA17 motor to Acme lead screw shaft coupling

I needed a shaft coupling for my 5mm NEMA17 stepper to Acme 3/8" lead screw, and I also needed it to be svelte enough to fit within the motor's standard color width. This is what I came up with.

There are two tightening screws on the collar - M3 x 10mm is a good choice here, and I recommend washers to give better compression. There is also a captive nut and hole for a M3 x 8mm (or 10mm) screw against the stepper's shaft to prevent backlash. Tighten the two side screws first, otherwise the