Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:4879716.

This jig was designed for fixing ball bearings to carbon rods for a Kossel / Delta printer, to ensure that all the rods are exactly the same length. It is designed to suit 10mm diameter balls. It has plenty of clearance at the front in case of any stray glue, and has a few flats included in the design to make it easier to measure the distance between centres etc.