Prusa i3 Y-axis carriage for 4 bearings

thingiverse

When using stainless steel y axis rods and the standard prusa y axis carriage with Igus RJZM bearings, I was having some twisting and binding issues, causing failed homing/failed prints. I decided to try a 4 bearing carriage to relieve the drag imbalance between the two sides and stop the twisting/binding. This fixed all the problems and now prints silently with zero twist and bind. Static and dynamic friction have increased slightly vs a 3 bearing or LM8UU solution, but doesn't affect printing. My MK3 clone now prints better than my friends Original, and is silent in Stealth mode. Build instructions: I made this on a 3 axis CNC miller and pillar drill (drill press). 1st operation was to centre drill all the holes for 2.5mm 2nd operation mill out the internal cutouts and bearing cutouts (6mm slot drill) 3rd operation mill the outer profile of the bed (6mm slot drill) I then drilled out the holes manually to 2.5mm and tapped for M3, except the holes by the bearing cutouts, which were drilled to 3mm for clearance. Use your bearings of choice. I used Igus RJZM-01-08 and my own bearing holders (see my things). Sorry for the photo quality - I don't really want to disassemble my printer now...!