SureTite_Z-Axis_Coupler

thingiverse

One file is for 5mm motors and the other is for 4mm motors and both go to 5/16th threaded rod. You can run a drill so 8mm will work as well. These parts are used with either steel or aluminum pieces which sandwich the printed part and squeezed together with 6-32 screws and nuts. You may thread the 6-32 into one side of the sandwich metal, yet i feel it best to use nuts, then you may use a tiny bit of locktite on them. Use 10-24 set screws, not just a screw. Screws just not made to grip the shafts of motors. You can use either 2 or 4 per axis. I used 2 and working well. (one 1/4 inch long and one 5/16 inches long per axis) Print them solid, set infill to "1", and print slow for detailed print. Mine work great, saved me from ordering some. Use printed part as template for drilling and take your time. Takes a bit of drilling, but worth it. I've found that a cordless drill running reverse works best in reaming out the holes. (on the plastic parts) Go slowly and use moderate down pressure and it will ream them beautifully.