Mendel90 Lead screw upgrade (LM8LUU, probe/bottom Z only!)

thingiverse

Update: Added pictures of the final revision. Working flawlessly so far, can easily run 10mm/s or more with no noise. I got really tired of the Mendel90's threaded rods.. they're slow, they take so many steps (3200 steps per mm!) and make the motors howl, they squeal. I also kept knocking out balls from the bearings too cause for some reason, the bearing mounts did not align fully when I printed new ones and half the time cracked the bearing mount when trying to press them in. I had tried to use bronze bushings and they were stuck immediately due to the slight misalignment, too. I ended up ordering a set of T8 8mm lead/2mm pitch screws (300mm) with matching nuts. You can get them as cheap at 8$ or so a pair on aliexpress. I found 2 sets of X-brackets for lead screws on here, but neither actually fit the nut. So I built my own, and replaced the dual bearings with a single LM8LUU while I was at it. The result is a smaller, lighter x-bracket set. Since the stock z-couplers couldn't grip the much thicker T8 rods, I also edited those to fit. However, since this was specifically made for my own printer, there are some quirks.. the most important one being that it is meant to be used with a probe or some sort of bottom endstop. **These will NOT hit the top endstop!** The second one being that the files uploaded are an improved version, which is essentially untested, but since I only added some things (larger space for the nut, nut traps to better mount the lead nut, fixed the nut trap for the x-axis belt mount), it should be functionally the same, or rather, better. *You will have to edit the steps per mm in Marlin*, either via terminal, gcode or by editing the firmware. Using these exact screws (8mm diameter, 8mm lead, 2mm pitch, 4 starts) the correct value is 400 steps. I also uploaded my sketchup file, in case someone wants to modify it further for their needs. Print with supports on buildplate only, 0.3mm resolution for faster print time is fine.