Rapman 3.1 Bearing Blocks, X and Y, for dual and single head machines

thingiverse

These bearing blocks will encase your linear bearings snugly and securely. Never again will you have to choose between damaging your rods, bearings, and plates by overtightening the bolts or leaving them too loose and having half the nuts spin off during superfast prints. >.< Updates from jcoffland's original: The orientation has changed; they are now set up to print flat. This means the weakest direction is no longer along the axis of the bolts, which in previous versions could cause them to delaminate and split. Because of the orientation change, the nut rebates now have lofted cuts so they can still be printed without support. The interfaces for the bearing holes and bolt holes have been modified so that the inside should not need filing. My bearings slid in perfectly straight off the printer -- snug but smooth. There is now a version for the dual head carriage as well as the single head. Instructions UPDATE: I've uploaded the IGES files. Let me know if anything's missing and you need it, it's been a while since I looked at these. I considered shaving off a couple mm per Fred_T below, but my blocks snapped over my rails with no problem. Print one and if yours don't you might think about modifying the print. They do take some force but not undue amounts. I also didn't run into warping or shrinkage with my ABS but that's probably machine-dependent and might also be due to my running at 2 or 3x speeds :). If you see warping his suggestion of decreased infill is a good one. Print with your favorite settings. No need to go overboard since there aren't really any bending loads and the bolt loads are in the strong direction. I recommend somewhere around 25% infill (or even less if you have shrinkage problems) and 2 extra skins to help with the nut recess overhang. You will need one of each file except that there are two versions of one of the X axis blocks; you will need the one that corresponds to your carriage setup. Both carriages need three blocks and two are identical, but the back block on the single head carriage and the front left block on the double head need a cutout for the extruder bolt heads. The two identical X axis blocks are actually together in one STL file, but if you need individual ones let me know. Install as per jcoffland's original blocks. The big top acrylic plates stay; these just replace the bottom plates. One important note: I don't like jcoffland's method of keeping the X belt holders rigid; it puts too much strain on the carriage plate for my liking. Then again, I print kinda fast, and also I am a wuss and have seen too many acrylic parts snap under fatigue. If you're comfortable with it that's cool. Otherwise, here's what I did (unfortunately it takes extra hardware, which makes it a rather inelegant solution): Get six M5 x 40mm bolts, and fasten in the X blocks as usual but use 4 of the slightly longer bolts, two in the front and two in the back. Use the other two 40mm bolts as the belt holders instead of the original 35mm. Take the original bottom carriage plate and place it underneath the bearing blocks, around the ends of the 40mm bolts. Secure the plate with a washer and second nut on the ends of the 4 long bolts that go through the bearing blocks (see picture). This avoids any cantilever on the belt holders. NOTE: Using these bearing blocks will make your axes 0.5 mm taller. Installing them on both X and Y axes will raise your extruder 1 mm (ish). You'll need to re-set your Z height or adjust the Z limit switch trigger bolt. Or both.