These X-ends work the same way as the original AO X-ends but are compatible with 3/8 inch ACME lead screw thread and nuts.The parts we used are McMaster Carr parts: -3/8" 12 Brass ACME nut: #95155A111 -3/8" 12 plain steel ACME rod 36": #98935A817You will also need to drill out your coupler or print a new one to fit the 3/8" threaded rod.See thing http://www.thingiverse.com/thing:13228 for instructions. Everything is the same except the change for the different ACME nut.