Customizable Prusa MK3 Y-axis Bearing Holder

thingiverse

This item allows you to press-fit sleeve or slide bearings for use with the Prusa MK3 y-carriage. The largest bearing it can support is 15 mm by 25.7 mm (outer diameter x length). Use it only with sleeve or slide bearings that are not enclosed, as these are weaker and designed to be pressed into a housing or block. Avoid using U-bolt mounts, which can deform the bearing. It will also compress some bearings to achieve the specified fit and minimize play. Igus bearings are press-fit bearings. The inner diameter adjusts only after being pressed into the proper housing bore with a recommended (H7) tolerance. The oversized dimension before pressing in can be up to 2% of the inner diameter, allowing for secure press-fitting and preventing axial or radial shifts in the housing. Note that lack of axial shifts means your smooth rods are more likely to bind if they're not parallel. This is why Prusa sticks with U-bolts. I designed these items with the drylin RJ4JP-01-08 bearings in mind, which don't officially need a press-fit but can be compressed to fit smooth rods of different tolerance specifications, reducing play. Customizer settings: 1. Bearing OD: set this to the specified bearing outer diameter. 2. Bearing OD loosen: how much to loosen (or tighten) the bearing press-fit. 3. Bearing lip: whether to print a lip or not. A lip stops the bearing from being pushed out of one end. 4. Bearing LN: set this to the specified bearing length, applicable only if you set bearing lip to true. I've attached STLs for RJ4JPs (and different compression amounts). Addition: I initially used RJ4JPs on a 4-bearing y-carriage MK2S replacement frame (P3Steel), which worked well for many months. However, I noticed excess wear and increasing play from my RJ4JPs after about 4 months, so I switched back to the original LM8UUs. Your mileage may vary.