4 MM TO 5MM Motor Shaft Bushing

thingiverse

Initially, I purchased NEMA 17 motors from eBay, expecting them to have 5mm shafts. However, upon removing the pressed-on pulleys, I found they were actually 4mm. To avoid redesigning and printing new pulleys for my Wade's extruder and Printrbot setup, I came up with an alternative solution. I printed two of these on a Makerbot Replicator 2 using the best settings, which took about 2 minutes. For easy assembly, slide the bushings onto the motor shaft first (the fit is designed to be tight) and then slide the 5mm pulley over it. While you can use super glue to secure the parts together, I found that the snug fit was sufficient, and a grub screw was more than enough to keep everything in place.