Z Stepper mount on top of 2020 extrusion

thingiverse

i wanted to add more z-screws to my Tronxy x5sa-400. quad bed screws eventually. i have seen several adapters and brackets for making this work, but none have worked exactly how i wanted. the problem with the tronxy design is the z-axis steppers sit right on top of the extrusion. they have brackets/sleds that are on the back of the stepper that hold it to the extrusion. unfortunately i needed 2 more and on top of that they wont fit correctly where i want to put the motors (off the corners of the bed on each side). there are a couple of plates here that do the same thing, but in all my tests they weren't rigid enough and the stepper could be seen rocking back and forth on top of the extrusion. so i decided to design my own. you will need to replace the screws that hold your stepper together with ones aprox 5mm longer plus a washer. you could probably get away with just doing 2, i did all 4. there are 4 mounting holes, 2 on the top of the bracket and 2 on the side supports of the bracket. for the side supports i use ball spring t-nuts that are already inserted into the extrusion. i get the close, and lightly fasten the screw to them, then i can slid the sled to the right place before tightening everything down. screw holes for the extrusion are for M4 cap screws. the stepper holes are M3, the standard size for nema17