Simple handle with printable T slot nuts. All you need extra are bolts and nuts. Curved shape prevents collision with X axis motor cables.
Provided STLs are designed for M3 x 16 bolts and M3 hex nuts. You can modify all sizes in .scad. You can switch to square nuts as well.
Print nuts on sides with 100% infill.
Handle has one side flat. This makes printing very easy and the result is very strong.
The author hasn't provided the model origin yet.