Seth Thomas Lyre movement - Half Hour Strike ?

mrclockman

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Feb 1, 2007
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I am servicing a friends clock. It is a Seth Thomas Omaha (City/College series). It has a Lyre shaped movement stamped 'Thomason'. Mechanically it looked in good shape (see pictures). I oiled it. I glued a couple of loose joints on the case. My friend said that occassionally (how often is that?) he would hear it strike an hour ahead of the actual time. (e.g. strike 8 when it was only 7). I put it on my Microset and only a few hours afterwards found the graph showing a 13 strike spike. It had struck 6 & 7 together. I reset it and has run without a problem for 3 weeks.

Does this movement have a 1/2 hour strike? I cannot see where it does. Parts of the two geneva stops are missing so I am not sure if I am not observing some other missing parts.

Thanks in advance for any insight or comments.
 

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harold bain

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If it had one, it would have been a passive strike, as the countwheel is only set for the hour strike.
Most likely it never had a half-hour strike.
 

Willie X

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Feb 9, 2008
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mrc,

A pretty good rule of thumb is: if it did it once, it will do it again ...

Likely culprits are: count wheel friction washer loose, count finger not dropping evenly in the deep notches, burr on tip of count finger, bent or worn pin/s on the pinion that drives the count wheel, rounded tip on the warn lever, warn lever not dipping low enough at stop, etc., etc.

This one has 'gravity only' to keep the levers down. It should work fine that way, but I have seen quite a few where springs had been added. This probably isn't a bad idea, if you can't find a clear fix otherwise.

You out there Jay? I think this could be added to the 'improvements' list, would for me anyways.

Good luck, Willie X
 

shutterbug

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Harold is correct that IF it had a 1/2 hour strike it would have to be a passing strike. You can look at the minute arbor (center one) and if it has two lift wires opposite each other, then it should strike 1/2 hours. Otherwise it's designed for hours only. Willies' comments will help you sort out the double strike problem. Could also be a stop lever issue .... when you get it cleaned up and on the test stand let us know if it's still doing it. You can fix that without tearing it down again :)
 

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