What life can be expected from a long-case clock if the pinions are made from unhardened steel, either mild steel which has not been case-hardened, or tool steel in its annealed state?
- posted
18 years ago
Pinions and arbors with unhardened steel?
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- posted
18 years ago
50 years plus? A difficult question to answer. I've seen clocks from the 1760's with pristine pinions and some from the 1950's with knackered pinions. The quality of the steel is the issue here. Obviously in the 1700's steel was an unknown quantity and varied in carbon content from iron to (possibly) silver steel. Many clocks have survived the 250 years unscathed others have not but the added variable is that we don't know how much work any given clock has done.
There seems to be a number of the cheaper '60's clocks made with unreasonably long pinions which may have been because they were made with the intention of moving the wheel on its arbor to an unworn part of the pinion when the pinion wore to an unacceptable level. So I guess they were made with soft pinions. Properly hardened pinions are probably good for 100 years plus depending on usage.
Bottom line, I haven't a clue! Why do you ask?
Mark
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- Vote on answer
- posted
18 years ago
Examples of such pivots may be found surrounded by black guck in some Hermle movements. Tool steel such as O-1 or silver steel should definitely be hardened. I've been told that case- hardening may result in more distortion of the workpiece than quench-hardening of Carbon steels, but I've never tried it.
Broken pinion or just grooved? Or a new clock? /mark
Plod's C> What life can be expected from a long-case