Summary

Upgraded versions of Ichibey's Sakura Cube parts.

Instructions

Print with 2-3 shells and a lot of infill for stiffness.

All 2020 mounting holes sized for M4 bolts & washers. You can use M5 if you drill out the 4.5mm holes a bit bigger.

Motor brackets:

Idler brackets:

Intended idler bearing shaft is a M5 lag bolt 60mm or longer
Designed for these flanged bearings: http://www.amazon.com/gp/product/B002BBGNOI but larger can be used (up to 15mm flange diameter should fit)
Depending on your printer's dimensional accuracy, you may need to drill out the idler shaft holes. On my R2x printing in ABS at 100.0% scale, they are a TIGHT fit to an M5 lag bolt. If you drill them out loose, use a nylock nut or some loctite on the M5 shaft to make sure it can't spin out.