Expert: John Newman - 11/13/2010

Question
I have a Seth Thomas Brown Marbleized Adamantine Mantle Clock Ca 1890's. I need the key for setting the speed of this clock. I have the winding key. Can you help?  

Answer
Ron, first, the key that is used on this type of clock is called a double-ended key.  On end fits the winding arbors of the clock and the other end fits the rating arbor.  There are no single keys for the rating arbor, unless you could find a small watch winding key that would fit.  In selecting a key, it has to fit perfectly on both ends.  The winding part has to be loose enough to be inserted on the winding arbor without binding, but not so loose that it wobbles.  That can cause wear or slip, which can be disastrous if it slips and the spring lets go and damages the clock and your hand.  The keys are numbered for both ends, but unfortunately different manufacturers are not consistent in their sizes.  Also the arbors can wear over time or a damaged arbor is sometimes trued up by a clockmaker, requiring the use of two different size keys, unless the arbor is replaced.  The fool-proof way to select the key is to take the clock in to an experienced clockmaker and have it fitted.  If you don't have a clockmaker in the area, I do have some ST mantel clocks in my shop and could fit a key and send to you with the hopes it would work.  Contact me at my shop email address below and I can reply with the details.  One further note.  Does your clock have a pendulum bob that is adjustable, that is with a small round nut at the bottom of the bob?  On these older American clocks, the rating adjustment on the dial is very unreliable, as the rating assembly has become worn and varies quite a bit.  Some clocks were furnished at the factory with the adjustable bobs in addition to the dial adjusters and clockmakers often substitute the adjustable bobs for more accurate rating.  Trying to rate a clock with a dial adjustor can be rather frustrating.  Also, the reproduction replacement assemblies leave a little to be desired.  At any rate, get back with me and we'll see what we can do.

John Newman
The Village Clocksmith
Old Prattvillage
Prattville, Alabama

klokdok@juno.com

Note:  Because of my commitment to answering Allexperts questions within a prescribed time limit and the large backlog of clock work at my shop, I regret that I cannot answer personal email questions on a timely basis, other than Allexperts follow up questions.