Pour les francophones : http://www.ouinche.com/impression-3d-z-wobble-sur-prusa-i3/ This version is for M5 Z axis. You can easyly adapt the skate for other diameter and then share it ^^ ) EDIT : Addition of M6 and M8 skate for 6 and 8 mm threaded rods.Principle : -- Decoupling the traction and the guidance of the Z axis. Traction is now assumed by the skate. Guidance by the X motor and the X idler. If your threaded rod is not straight as your smooth rod ( and theren't ! ) the skate will move independently of your Z axis. You may try it with your classic ( or rework , or enstein , ... ) X motor and the X idler but I don't know if ther are enought surface in contact to do this correctly. So I re re worked the X motor and the X idler to increase the surface of contact with the skate. And I add on the X idler a belt tensionner system. I add a X endstop support too. Needs -- 2 M5 Nuts ( skate X 2 ) 3 M4 Nuts 3 M4 Screws Of course the plastic pieces below ( print 2 skates, one for each Z threated rod ) Instructions : -- Embed the M5 Nuts into the skates ( one nuts per skate ) Assemble your X motor and your X idler ( Instruction may be found at http://www.thingiverse.com/thing:247992 djvdpant is the farther of this design ) Cons : --