Trundle Questions

[bangster]

Question 1: Anybody have any luck straightening bent trundles in a lantern pinion, while they're still in the shrouds?

Question 2: How much wear in a lantern pinion do you allow to get by, before rebuilding it?

bangster

[Eckmill]

If a lantern pinion leaf or trundle is bent, then it must be replaced.

Further, the cause of the damage should be identified and the wheel train inspected for other damage.

Along with the bent pinion leaf, the arbor may be bent or a pivot bent and certainly the mating wheel's teeth may have damage or its arbor bent.

Too, if a lantern pinion leaf or trundle is bent, then the wire is soft. The trundle wires should be of good steel and resist bending and wear.

How much wear can be tolerated in the pinion leaves? Minimal. The fix is relatively simple. A movement should not be reassembled with lantern pinion trundles showing wear.

[bangster]

My Sherlockian skills tell me that this clock at one time suffered a mainspring explosion. Evidence: replacement mainspring, and eight teeth replaced in the barrel gear. No idea when that happened, but some time back. No damaged teeth in the other wheels, but damaged lantern pinions may have happened at that time.

bangster

[Len Lataille]

A bent trundle must be replaced, agreed. But slight wear should not be a problem, especially high up the train.
I had a mantel clock recently that had mainsprings that were much too powerful. Every trundle in the clock showed signs of wear. All in both second wheels pinions were replaced and the worst ones in the third wheel pinions. Further up, with the correct mainsprings, everything should be fine for years to come.
If the fan had been noisy, I would have done that one as well.