This jig is used to make consistent length magnetic ball joint arms for the Cerberus, Cerberus Pup, and other Rostock deltabot printers. Requirements: 3/8" steel ball bearings 3/8" x 3/8" cylindrical neodymium magnets Carbon fiber shafts, such as arrow shafts Print two and mount them onto a length of wood at appropriate distances using screws. NOTE: The provided STL uses a 7.28mm diameter carbon fiber rod in the model. If your CF rod has a different diameter, download the SCAD and edit it in OpenSCAD, adjusting the cf_rod_dia variable appropriately. The way I did it to keep the epoxy from getting all over the place is I glue one ball at a time using the following procedure: When you do the second ball, rotate the jig so that the second ball is now at the bottom and repeat steps 1-8. What this does is uses gravity to let the epoxy flow down to the ball and stick to it. It's slow, but it works. :)