I have made this in PETG white, 0.16mm-40% fill with support.
part 2 made in 0.12mm-40 fill, is attached with 2 pcs M3x16 or 12mm, 4mm pneumatic Fitting 1/4, 1.25 threads.
The product is easily clamped over the step motor.
Parts can be mobified at Onshape.com
Part 1. Onshape
Part 2. Onshape
The author marked this model as their own original creation.