Interesting to see this presented as a puzzle- I've never thought about it academically, but knew the answer immediately from hands on experience. Slipping meta

Interesting to see this presented as a puzzle- I've never thought about it academically, but knew the answer immediately from hands on experience. Slipping metal bearings over metal shafts when the inner diameter of the bearing is less than the outer diameter of the shaft is a piece of cake if you throw the bearing into a toaster oven for 15-20 minutes first. It'll drop right on right down to the base no problems. When they're unheated you wouldn't be able to get them on and down even with a significant amount of brute force hammering.