UPDATE: I have added the OpenSCAD source used to generate this pulley, plus the idler for a 608Z bearing.Here is a printable Synchromesh drive pulley for 3.81mm pitch cable with a simple interference fit and 15 grooves. I'm using this on my printers with results just as good a the purchased commercial pulleys. Here's a video:http://youtu.be/woZara2NKUcIf you're not familiar with Synchromesh Cable see my other thing:http://www.thingiverse.com/thing:15923In the future I plan to release a version with a set screw or clamp etc. So far this hasn't slipped for me and I've been printing non-stop for several hours with it.Print and enjoy a simple cable drive system! Now you don't need steppers with long output shafts because cable is so narrow.You'll also need to change your steps-per-mm in your firmware. For standard 1.8 degree steppers these are pre-calculated the values:no microstepping: 3.500 1/2 microstepping: 6.999 1/4 microstepping: 13.998 1/8 microstepping: 27.997 1/16 microstepping: 56.993