i3 y axis to threaded leadscrew with radial bearings 'nut'

thingiverse

This is work in progress, i'll upload sources when i'll finish and when i'll have time as it's pretty complicated array of openscad scripts included together :) perhaps i will just zip whole folder... this project is an attempt to convert Y axis of my large i3 (1m in Y dimension) to leadscrew. Obtaining strong enough belt was expensive so i've decided to give leadscrew a go. I was inspired by threadless ballscrew designs, but i wanted to use threaded screw, so i've modified the bearings appropriately. it is designed for 6x 3id 10od 4height bearings (693?) you need to print "8mm threaded rod_675_24.stl" file twice then apply 693 bearings to it and assemble it with "y-ballscrew_imitation.stl" then you need all 10mm rods i3 . you do print : "idler_y_bearing_mount.stl" and insert it like third 'y corner' but in the center of 10mm threaded rods. this will hold motor, and two 10x30x9 7200 bearings. you need to fix threaded rod to 7200 bearings with four m8 nuts . first fix two nuts against eachother, and then cancel any backlash on the leadscrew on the other side and then tighten another m8 nut against just adjusted one. final step is to connect rod and motor with coupler. motor is nema23 because only those are high speed - this is needed to reach decent printing speeds. enjoy. edit : with 2V 2A motor driven by drv8825 running with radiator (perhaps well above 1.5A) max axis speed i could achieve, even at 1:1 microstep rate , was only 12mm/s. this is well disappointing. motor does have plenty of torque though so i guess gear-up mechanism makes sense. also bearings are for m10 rod, so i guess it's worth also starting off with m10 - i will post m10 version of rod bearings sometime later.