Summary Remix of mska's thing. Added a hole suitable for this part. There is no hole at all on the original thing. https://www.robotdigg.com/product/961/POM-Nut-for-RobotDigg-Linear-Steppers Also added slots so the bolts can tighten the part onto the smooth rods and fixed some busted geometry. I suggest you don't use this at all but if you must you might as well use a proper nut on the threaded rod. There is no reason to stop using the smooth rods on your Prusa.