seth thomas ratchet wheel

[GandalfPC]

I am working on a nice 18s 17j Seth Thomas model 5 (serial #233604), and found that two teeth are broken off the ratchet wheel. The missing teeth are not next to each other, and I am wondering if I can safely use the broken ratchet wheel while I am testing the watch, or if it will possibly cause damage.

Part two of my question is, of course, where do I find a repacement?

http://JasonGoldman.com/teeth.jpg


[This message has been edited by GandalfPC (edited 10-05-2002).]

[GandalfPC]

I am working on a nice 18s 17j Seth Thomas model 5 (serial #233604), and found that two teeth are broken off the ratchet wheel. The missing teeth are not next to each other, and I am wondering if I can safely use the broken ratchet wheel while I am testing the watch, or if it will possibly cause damage.

Part two of my question is, of course, where do I find a repacement?

http://JasonGoldman.com/teeth.jpg


[This message has been edited by GandalfPC (edited 10-05-2002).]

[Steve Maddox]

While obviously not an "ideal" situation, in most instances, large gears and wheels will still work with missing teeth, as long as the missing teeth aren't consecutive, and as long as the gear with which the damaged one engages is also of a relatively large diameter.

Broken teeth in ratchet wheels most often result from slipping clutches, which as a watch is wound, allow the ratchet wheel to slip backward until the click suddenly and abruptly engages. Of course, that eventually "hammers" off teeth, and it's a common problem on certain brands and models.

As for where to find a replacement wheel, I really don't have any words of advice. Somebody somewhere probably has a "parts movement," but I don't. Of course, it would be possible to install some new teeth in your old wheel, or even to make an entirely new wheel, but both of those options are relatively "extreme," especially since it's a part that shouldn't be too tough to find.



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Steve Maddox
President, NAWCC Chapter #62
North Little Rock, Arkansas

[GandalfPC]

Yes, I had remembered hearing that it would be ok to use a ratchet wheel if a tooth were broken, but wasn't sure where I had heard it or if it was correct.

Of course after hearing it from Steve, I know I can tuck a new bit of knowledge under my cap, and tomorrow I will have the joy of hearing that ol' Seth Thomas tick...

Thanks again :smile:

I will also take a good look at the cluch and see if I can detect any problems there - is the slipping caused by the cluch design, or is it a correctable problem by adjustment of the sleeve or some such?

[This message has been edited by GandalfPC (edited 10-05-2002).]

[BrianC]

I should have one of those rachet wheels. E-mail me.
Brian C.

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[Steve Maddox]

Slipping clutches often result from a weak or broken shipper spring, but the problem can also result from something as simple as gummy oil and/or grease in the clutch. With "modern" type clutches, the ratchet teeth between the clutch and winding pinion fail to remain engaged, but with older "rocking bar" type devices, the winding pinions can "ride up" and disengage as the watch is wound. Of course, with either type mechanism, a worn or misadjusted pendant sleeve can cause the same sort of problems.

In any event, suffice it to say that you need to find out what's knocking teeth off the ratchet wheel before you knock any more off. Your existing ratchet wheel is in bad enough shape as it is, and if you're lucky enough to find a replacement, you certainly won't want it to become damaged as well. (If, after thorough examination, you absolutely cannot find any faults, it's possible that someone in the past already corrected them, and that the ratchet wheel has been the way it is now for a long time).

Again, I hope this helps!

SM