I need to make a frame to hold a worm spur gear. I suspect finding bearings the size that I will need may be difficult. But what about turning bearings out of Teflon. This spur gear will turn about 1/12th rpm, so this should not be a demanding application. I already have a 1" cylinder of Teflon so this will be easy. Teflon is not a corrosion problem with carbon fiber. I almost wonder if i should have used these instead of bearings for the axes. I could have skipped the whole use of threaded inserts. I could have tapped the blocks instead. These axes will typically move at 1 rev/day, with higher rates for a few seconds at a time. It might still be worth doing that.
There are other places where I had considered using bearings which were not strictly necessary. The ears that hold the polar axis support to the mount base might have used bearings. Teflon is not only easier but this is a situation where Teflon's tendency of stiction (it turns but only if given some push) is actually an advantage. That support needs to move in the ears, but not real easily.
Teflon is 2.2 g/cm3 so at the high end of carbon fiber composite but still lighter then stainless steel bearings.
Acetal is apparently not much worse on friction and it taps more easily. Teflon's softness means that it tends to flow back after tapping.
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