/diy/ - Do It Yourself

I'd like to share my recent discoveries about Igus plastic bearings.

As some of you may know, even though they're great for silent operation, the clearance they have is terrible which results in a high amount of slop. Igus even mentions on their site that the're designed to be pressfit in order to be usable, but doing a proper pressfit on a 3d printed part is quite tricky because you need a very precise bore. I've also tested the RJ4JP model which is advertised as "ready to use for 3d printers" but they too have about 40-50 microns of slop. The only ones that supposedly have the desired tolerances are very expensive at about 15$ for a single piece. Thomas Sandladerer mentions this in one of his videos.

I tried designing a clamp that would let me squeeze the bearing into a proper diameter by fine-tuning the clamping bolt. Even though it worked to get rid of the slop, i found out that the bearing gets deformed into an ellisoidal shape. This results in an unevenly distributed contact surface, causing too much friction for the thing to slide easily on the rod.

And here's the one weird trick i did to solve this - just cut the bearing. This makes the inner diameter a little smaller than it needs to be, so when you insert the rod you get perfect contact with zero slop.