The file 'Customizable Handles, Drill, Screw, Brush & Bit Holders 3D Printer Model' is (stl,scad) file type, size is 525.4KB.
I like Acarius10 handle a lot. Here is a rewrite, cleaner and with a few additional options, such as variable number of trapped nuts, intermediate space for a magnet (e.g. to support hex screw bits)
I used the one above all the time for some years now. I flattened the base of the 3mm drill bit so it does not rotate freely.
20181217: fixed inverted nut data (thanks intermayer & lapope47!)
handle-hexBit-magnet.stl | 1.3MB | |
handle-hexBit.stl | 2.0MB | |
handle-tapM3.stl | 1.6MB | |
handle.scad | 3.6KB |