Summary

Simple handle for screw-mounting with through-hole and rounded ends.

Instructions

Part is oriented with the screw end down, so as to print without support. You may need to use a raft if your bottom width, radius and hole dimensions do not leave enough surface area for adhesion to your build platform. I was able to print one in PLA on blue tape without a raft.
Variables screw_head and screw_shaft are diameter measurements of the screw you intend to use. Leave a little extra for clearance. Screw_sink is the amount of material that will be left between the bottom of the handle and the top of the screw hole. Too low a value will weaken the part; too high and your screw may not penetrate enough. Resolution affects outside curves only. Leave high for a smoother part, or experiment with a lower value for a faceted appearance.
If you want the bottom edge flat, use a very small value for bottom_radius, like 0.1, but not zero.

customizable handle