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Recommended Interference fit for Black Acetal

I have been using the following Chinese acetal, and it does seem to be adequate. The key to reasonable pricing is to buy the un-machined extrusion, which is imprecise and may be curved like a banana.

https://www.amazon.com/gp/product/B01KNNQ79Q/ref=ppx_yo_dt_b_asin_title_o00_s00


Polymersan Acetal Copolymer Plastic Round Rod 2" Diameter, 12" Length - Black Color

Freekin OUCH! $$$$$$ $40.00 a foot! I can buy 303 round for less than that. McMaster has it for $25/ft.
I buy tons of 2" and pay about half that. I also throw away loads of 2" black acetal stubs that are too short to make another part.
 
Freekin OUCH! $$$$$$ $40.00 a foot! I can buy 303 round for less than that. McMaster has it for $25/ft.
I buy tons of 2" and pay about half that. I also throw away loads of 2" black acetal stubs that are too short to make another part.
McMaster is not the only source, and isn't really suited for bulk supply. And Garolite isn't the only brand.

Compare with Delrin. Nylon is cheap and forgiving; maybe it's good enough.
 
It seems like your tapered bearings will be clamping the material axially, right? Can you use a beefy belleville washer on the shaft to account for some amount of expansion and creep?

At 150 degrees F above ambient you're looking at 0.0015" of expansion per inch of bore. So you'll need more than that amount of elastic interference on the bearing to not loosen due to thermal expansion. But personally I think even if it creeps to a slip fit it won't matter as long as you have that axial compression.

I have seen bearings with a 30 or 45 degree outer race to accommodate a lot of expansion along with springs on the shaft, but that seems overkill.
 
Just went through an unpleasant experience with Delrin. Needed to make a 1/2 inch thick electric isolator with 8.5" male and female rabbet fits. Found out after we made it that Delrin expands about 10x that of steel from temperature. I assume a 100 deg F rise on the Delrin so got concerned about the different expansion rates. Delrin is rated to 180 Deg F (at least this one from McMaster Carr) so was ok for temperature as we were limited to 170 deg F.

Put it through some heat runs. They didn't listen and went to 200 deg F so slightly exceeded publish temp limit. 30 deg ramp from 70 deg F to 200 deg F held at 10 minutes and 30 minutes down.

Results were not good. When we took it apart the 8.5" rabbet fit was 0.030" smaller than what it was after it was machined. Totally unusable.

Getting remade with G10.
 
Why not make a steel hub to take the bearings, and then fit an Acetal tyre to your hub? I would use bolts or something similar to hold the tyre to the hub.

BTW, I reckon the press fits mentioned have been too light. Plastics can easily handle something like 0.25mm interference. But I still wouldn't trust the bearings fitted to acetal, given the forces and heat they are going to experience. The taper roller bearings suggest heavy side forces.
 
Melding Strostkovy & PeterS ideas, how about a split hub (steel) with 'turned in' rims aka 'shallow cups' to grip the acetal tyre by an annular groove each side, tapered to assure grip regardless of radial expansion or shrinkage, by means of the axial force of the Bellville spring? The 'tyre' can overhang the sides thus avoiding 'metal to metal' in the spinning.
 








 
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