Ho semplicemente postato questa idea che ho trovato su questo sito
http://www.p3-d.com/twist-drill.html

nstructions and Usage:
Works with #37 (.104" / 2.64mm) drill bits
May accommodate slightly larger or smaller bits (use at your own risk)
Download and print all 4 STL files (Helix, Nut, Hand Grip, Finger Rest)
Suggest printing at fine layer height (.1mm)
Suggest a highly calibrated printer
Suggest using raft on the helix component
During assembly, it helps to put a tiny drop of grease on the tip of the finger rest before pressing it into the helix. It should snap in snugly, but turn freely