Prusa i3 Y-axis carriage for 4 bearings

thingiverse

When using stainless steel y-axis rods and a standard Prusa Y-axis carriage with Igus RJZM bearings, I encountered some twisting and binding issues that resulted in failed homing and failed prints. I decided to try a 4-bearing carriage to address the drag imbalance between the two sides and eliminate the twisting and binding. This solution fixed all my problems and now my printer operates silently with zero twist and bind. The static and dynamic friction have increased slightly compared to a 3-bearing or LM8UU setup, but it doesn't affect printing performance. My MK3 clone now prints better than my friend's Original, and operates in Stealth mode without any noise. Build instructions: I fabricated this on a 3-axis CNC milling machine and pillar drill (drill press). The first operation was to center-drill all the holes for 2.5mm. The second operation involved milling out the internal cutouts and bearing cutouts using a 6mm slot drill. The third operation involved milling the outer profile of the bed using a 6mm slot drill. I then manually drilled out the holes to 2.5mm and tapped them for M3, except for the holes near the bearing cutouts, which were drilled to 3mm for clearance. Use your preferred bearings. I used Igus RJZM-01-08 bearings and my own custom-designed bearing holders (see my projects). I apologize for the poor photo quality - I'm not eager to disassemble my printer!