teflon therm coef expan = 200 E-6
200 deg.  change --> .04 change
* pi --> ~ 1/8 change in circum.
--> for  1/2" dia. bearing, want 9/16" hole

George, change in circum is proportional to change in diameter
(all linear dimensions must change proportionally)

James? length = dia * Pi 

delta-dia = 0.04 * dia
delta-circum = 0.04 * circum
delta-circum = 0.04 * PI * dia