My 3D-printed engine design is stumbling towards being printed, but as it will take about 24 hours and use lots of plastic filament, I want to improve it as much as I can first.
Friction is worrying me because plastic running on plastic is more like a brake than a slippery bearing.
When I did Meccano, it was recommended to reduce friction by fitting a loose washer on the axle to separate the wheel hub and frame, as in the silvery example just visible in the photo:

I suppose the idea is the brass hub slips against the washer, which is free to rotate and slips against the frame as well.
Attractive to think the arrangement reduces friction, but does it work? Another way of looking at it is it doubles the braking surfaces and wastes energy spinning the mass of the washer. The arrangement seems likely to increase friction, not reduce it.
Slightly different case maybe because the contact pressure is much higher, but I think bolts tightened on to a washer are less likely to work loose, not more!
I'm thinking of using a plastic printed washer to reduce friction on my plastic engine. Worth doing if it decreases friction, otherwise a waste of printing time and plastic, perhaps adding friction to the engine as well. What do the team think?
Dave
Edited By SillyOldDuffer on 21/06/2022 13:00:45