Edit: Don't bother with this. Instead use Prusa's new Mk3s 2-piece design with integrated belt tension adjustment which will work on Mk2 and above printers. See "Y-axis parts: here:
Wr125x's Y-belt holder was a little too tight for one of my Mk52 12v heatbeds, So I elongated the bolt hole closest to the front of the printer by ~1.5mm while keeping the other hole circular. This model ought to install on all generations of the Mk42 and Mk52 12v heatbeds.
Advantages over Mk2/Mk2s design:
- consistent with Mk3 design which is what Prusa determined is more reliable in their lab
- quicker install/assembly
- more stable since one hole is circular rather than elongated
Disadvantages over Mk2/Mk2s design:
- cannot adjust end stop location since holder cannot slide with respect to heat bed
Use default Prusa 0.2mm Fast settings except bump infill to 50% for added strength.