MakerFarm Pegasus 8" Lead Screw Mounts

thingiverse

These are lead screw brackets for my MakerFarm Pegasus 8" printer. Much thanks to @jlarsenwy for creating the original design, which I had to make some small changes to accommodate my recent Pegasus 8". I've uploaded those changes and some analysis in case others can benefit from it. Please visit @jlarsenwy's design for more information: https://www.thingiverse.com/thing:1989637 1) The extruder motor sticks out too far, causing it to hit the left bracket. To fix this, I raised the bracket with an offset block so that the motor goes underneath it instead of colliding with it. You can find LeadScrewBracketOffsetBlock here. 2) The 25mm-long M5 screws I used had large heads that didn't fit inside the recess of the left bracket. So, I edited the design and increased the radius by 0.5mm. Check out LeadScrewBracketLeft-5.5mm for the updated model. 3) On the right side, the end of the bolt that holds the delrin roller to the z axis sticks out too far, getting in the way of the right bracket. To resolve this issue, I used longer M5 bolts and some nylon lock nuts to mount the electronics away from the Z extrusions. Now, the bolt for the delrin roller can be flipped around, making room for the right bracket. For completeness, I've included @jlarsenwy's LeadScrewBracketRight without any changes. Analysis I started looking for an upgrade because my prints were coming out with a lot of ridging due to the stock threaded rods. To confirm that the rods were indeed the problem, I used a micrometer to measure the actual Z position across a range of Z travel in increments of 0.1mm. Although the micrometer only goes down to 0.01mm, the magnitude of the periodic error in the threaded rod was large enough to be quite clear. The period of the error sine is about 0.8mm, which matches the pitch of the rod. The chart above shows the error on the stock threaded rod (blue line) while the red line represents the error after upgrading to a 2mm lead screw. The image below shows a D12 print before the upgrade (left) and after the upgrade (right), and it's clear that the difference is substantial. You can find the D12 design here: https://www.thingiverse.com/thing:1043661