The Many Use Thing is a tool that I designed in Sketchup. It can be used for the following purposes:
To use as a Dremel collet tightener, slide the tool over the flat part of the collet and then squeeze the arms with your thumb and forefinger while twisting to tighten or loosen.
The 3/8" and 1/4" drive shafts are for sockets. After printing they will need to be "broken in". Trim up excess plastic and force a socket on and off a few times. After that you can be assured that once a socket is put on it will not fall off.
The hole in the middle is 1/4" so you can use it as a handle for bits.
I printed raftless which means the bottom layer squishes out a bit. Since the drive shafts have tight tolerances be sure to trim and taper any excess after printing.
The design has the 3/8" drive at 10mm square and the 1/4" drive is 6.4mm square. If you were edit the source file and extrude the height beyond 10mm then the 3/8" would no longer be the right size.