Worked with a lot of teflon in the semiconductor industry. Great stuff for fittings, etc. But it will deform under pressure. A clock puts a lot of lateral pressure on the arbors, more as you get nearer the power source, spring or weight. Teflon bushings would deform, leading to increasing bad depthing, leading to more friction, etc.
C. J. Klingman
Briarcliff, TX