4mm PTFE LM8UU replacement

thingiverse

PTFE LM8UU Replacement Disclaimer This PTFE bearing uses a sliding surface, which wears much quicker than drylin or steel ball bearings on a hardened steel shaft. It's only proposed as a temporary measure or for low loading applications. I personally will be using it for a pen plotter with a low loading mass. Introduction This printed bearing casing and cutting tool allow the user to print a very low friction bearing that fits normal LM8UU bearing holders. PTFE bowden tube is cut using a printed fixture and Stanley blade to slice a 4mm ID and 2mm OD bowden tube in half axially. Requirements Stanley blade 66mm length of 4mm OD, 2mm OD bowden tube per bearing Instructions Print the PTFE cutting tool. Insert the PTFE tube into the tool until it stops at the bottom of the recess. Using the Stanley blade, cut flush with the top of the cutting tool to leave a piece of PTFE in the cutting tool (this piece will be 22mm long). Slice down both helical grooves on the side of the tool, cutting the PTFE tube in half. You may need to grip the tube at the top to stop it twisting in the tool. Pull the PTFE tube out of the tool. Slice off the bottom 2mm of the two pieces of tube where the two halves are joined. Repeat twice with the remaining 44mm of PTFE tubing so you have six halves of PTFE tube. Print the bearing casing. Insert the PTFE pieces into the bearing casing grooves on inner bore. The PTFE might need a bit of persuasion to fit, so use a thin nose pair of pliers if it's a tight fit. Slicing a few mm off the end of the PTFE pieces will compensate for any less than ideal bridging on the inside of the bearing casing. Slide onto an 8mm linear rod and run up and down to check movement. Print Settings Rafts: Doesn't matter Supports: No Resolution: Ideally 0.1 Infill: 60%-100% Notes: Use minimum 2x perimeters on bearing casing. Check bridging moves on top of grooves for possible sagging.