Summary

If you're getting layer lines, then a wobbly lead screw might be the culprit. This mod decouples the lead screw nut from the frame, using magnets to hold tight and reduce layer lines, even if your lead screw wobbles by up to 3mm in any direction.

This design is for 2 and 4-screw lead screws with 16mm or 18mm spaces between them.

Note that you should try to fix any z wobble first by carefully testing your coupler, stepper, and lead nut locations before you add this mod.

Parts:

• 12 cylindrical 6 X 2 - 3mm magnets
• 8 4mm - 5mm ball bearings. (or spherical magnets)
• 2X octogon_16mm_8_ball_middle_1.01.stl
• 2X octogon_8_ball_outside_universal_16mm_18mm_1.01.stl

Assembly:

The magnets all have to align in the same direction (polarity) in each column of magnets and balls, and the magnets on each outside (top / bottom) part should be visible from the outside.

That means each side should have opposing (attractive) polarity magnets, and all the magnets in the middle part should alternate polarity.

When you assemble the middle, orient each side so that the rails are perpendicular to the other middle part.

Make sure the outside part is aligned in the same direction as the middle rail it's connecting to.

I've added a universal fit attachment part, so you can print the universal attachment and it will interface with 16mm or 18mm gap lead nuts.