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Antique Clocks/Seth Thomas mantle clock


I just bought this clock and after setting it up I find it is gaining time fast could you advise how to slow it down. My clock has a pendulum bob with no adjustments. I do have a hole in the center with s and F on each side. Am very new at this so must apologize if I am not correct in some of my guestions, Thank you

Inside that center hole you will see a square metal arbor. Originally the key to your clock had a small key on the back end. If you have that the small end should fit the small arbor. If you don't have the original key I would suggest you get a number 2 watch key. These can be found on Ebay new and will fit your clock. Either way, put the key into the hole and line up the square of the key with that of the arbor. Turn the key about 1/2 turn toward S. Let the clock run for a few hours and check it again. Go about 1/2 turn at a time and you can always come back if you go too far. Repeat this until the clock is accurate. When you turn the key toward S or F do not force it. These particular regulators are very prone to breaking and if it fights you stop and see a professional.
Here is what an original Seth Thomas key looks like.

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Barry W Macomber


My experience is mostly with 19th century American clocks. I can answer repair questions and can identify most clocks of this period. I cannot answer questions about non-American clocks.


Many years buying, selling, and collecting American clocks.

NAWCC 14,915

No formal education in this area.

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