Dirt-cheap, Dead Simple Magnetic Rod-end for Delta printers.

thingiverse

This is a cheap, simple, easily printable magnet holder for solid 6mm rod or tube based arms, designed to connect to a 10mm steel ball bearing which you can epoxy to your end effector or linear carriage. It uses cheap magnets and washers available for pennies on eBay. Simply fit a 10mm dia x 5mm tall magnet available readily online, using a dab of thin Cyano-Acrylate ("CA" or "Super") glue. Use another dab to fix your precisely measured solid carbon/aluminium/etc rod or tube into the other end, butting it up against the back of the magnet. Finish off with another dab of CA to hold a dirt cheap M5 nylon washer to the face of the magnet as the bushing and grease pocket. When the bushing wears out, pop it out with a craft knife or spudger (CA glue doesn't hold the nylon very hard) and fit in another. The "Extended" version is exactly the same but takes 10x10 magnets or two of the 10x5 stacked to add extra pull for heavier extruders and longer arms. This part was developed as part of a whole printer design, but I thought people might want to adapt it for other setups. It should scale quite easily to larger magnets and rods.