Taurus X axis for Prusa MK3 and MK3s

thingiverse

Go big or go home! That's the Taurus way: bold with purpose, unapologetic overachievement, innovative practicality, a dash of flair. I wasn't about to settle for another run-of-the-mill Prusa design, so I gave it the Taurus treatment. But, of course, it's still an XZ machine, which means limited options. Here's what I did: * Expanded bearing stance -> resisted flex, hopefully pushed resonant frequencies outside print bandwidth * Added backlash adjusters for Z lead screw * Perfectly flat belt drive path (except the stock version) * Tool-free belt tensioning * Tension doesn't affect drive geometry * Super sturdy fixed idler pulley * Reoriented print -> see note below * Motor shaft end bearing support (optional) * Full 4-point motor connection * Bearing screw clamps for easier assembly * X rod fine-tuning screws (ala MK2) * Added accessory mount point, e.g. for camera All this for free! Note that the photo is a prototype. The real one is much more stunning. Compatibility: Works best with Skelestruder and some other extruder mods that level the belt. Use the 'stock' version parts to work with stock Prusa extruder or comparable offset belt extruders. **Note:** I'm investigating an issue reported with stock extruder that fails X self test, so you may want to wait a bit. This axis upgrade is compatible with Bear frame as well. Backlash adjusters are experimental and optional. Idea is to remove backlash from Z axis since it uses a lead screw. These provide a gentle counter force. Additionally, I lengthened to span more than one turn (4 start screw) to average out milling tolerances, and positioned out of phase with main trap nut. Hopefully this makes Z motion more reliable and accurate. Print orientation. Who cares, right? Well in FDM you can resolve certain geometric features more accurately in one dimension vs another, depending on what you're trying to achieve. The X ends are where two axes meet, X and Z. Interestingly the Z axis has two interfaces, lead screw and smooth rod, but both use a mechanical interface, trap nut and linear bearing, that are themselves machined to high accuracy. So only the remaining X axis has a direct coupling between the smooth rod and the part. I reoriented the print to resolve this interface better for a stronger more accurate rod connection and positioning. It's so tight and snug I had to add an Eustachian tube to relieve air pressure! This nicely complements the Taurus Y axis and Taurus Z axis, but each is completely independent. See also Taurus LCD as finisher piece. **Update** 8/11/19: fixed stock motor to remove Mcap. Thinned support on PINDA pocket on idler side (r1c) for more easy removal. I also added all steps for non-stock version so folks can mod as desired. Please give attribution with your changes. **Update** 2/1/19: added r1b version of stock ends. **Update** 1/7/19: r1b version: tweaked idler rod holes, improved homing edge, added cap for easy pinion access and bearing clamp. Bl adjust has broader range and should align better.