View Full Version : Bearing material

11-10-2003, 07:12 PM
If I were to machine a bearing out of Delrin, what would I expect to hold tolerance wise over a 10 degree f fluxation?

11-10-2003, 08:18 PM
From what I could find, the coefficient of expansion is .000045" per inch, per degree F (melts at 347 deg F)

So for 10 degrees F, about half a thousandth expansion/contraction per inch of diameter.

This plastic also will absorb some moisture from the air, which means it can swell or shrink a fair amount. I am not sure how they would compute expansion due to this factor, but it is there, and should be considered if you are making a real close fit. It may get tighter than you thought you made it. :)