Most of the things I design don’t have moving parts, so I printed emmitt’s Gear Bearing as a fondletoy:
Setting the clearance to 0.5 produced a free fit with absolutely no cleanup or run-in required; the center hole is a sliding fit for a 6 mm hex wrench.
I should do another one with knurling around the outside…
The picture has strongly desaturated reds, which reveals the top surface a bit more clearly.
The Smell of Molten Projects in the Morning 