Flexible coupling ~ 5mm stepper to 3/8" lead screw

thingiverse

IMPORTANT You must turn down the stepper current for your z axis motor before using this coupling (if you print it in pla). On the standard one/two-up, the stepper currents are set too high by default and as a result, the steppers get very hot. This can actually allow the coupler to deform enough to become unusable, so be sure you turn down the current! Here is a flexible coupling I designed for my two-up 3d printer. It's design allows it to be printed relatively quickly, it has support for up to 3 set screws (although only 1 is absolutely necessary) and it has plastic spiral pieces in the center to allow for the screw to pivot if it is not perfectly centered. Requires at least 1 M3 nut and 1 M3x8mm or longer bolt . Notice that if your z-stepper gets hot during use, you may be required to use all 3 bolts. If you have just one and it gets too hot, it could force the coupler to permanently deform. Using 3 screws will prevent that problem. Fully compatible with the one/two up with the stock gantry or with stefanburgers 3d printed gantry.