Seth Thomas Clock Movement

Seth Thomas Clock MovementST IdentificationHow to Order STWhy Order STMovement IssuesHistorical Timeline

Please view these information tabs for assistance, there is important information needed for a new Seth Thomas Clock Movement.

Seth Thomas Movement Identification

Seth Thomas Movement Identification is done with the numbers on the back of the clock movement. The Seth Thomas name has been tossed around alot, from one company to the next. The short version of these take overs is we are left with three types of Seth Thomas clock movements. There is the Antique Seth Thomas that produced so many clocks during and long before WW2. Then we have post WW2 Seth Thomas using the German units, and these modern times the name can be found usually on battery operated clock dials. What made this name so famous is back in the Antique days they made there own movements and there own clock cases and the quality was astounding. After the war era they did not make any clock movements anymore but did use Hermle clock movements and this is what we are offering here. Hermle is an excellent quality German made movement for the modern world.

How to tell if the ST is Antique can be done a few ways. The easiest way is if the movement has no pits in the movement plates. What I mean is do you see all the little bumps in the below pic?

Seth Thomas Movement Identification

The picture displays what I mean by small bumps in the movement plates. So if this sort of design is on your Seth Thomas clock movement we now know some interesting things. The movement was produced between 1950 and 1979, and it was made in Germany. This also means you have a good chance of getting a new movement for the clock from

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Ordering German Seth Thomas Clockworks

Ordering German Seth Thomas Clockworks is done with the movement number off of the back. But it needs to be converted because they really did not make any movements after 1950, they were made by Hermle of Germany with the ST number system and ST name on the movement. So really its a Hermle in disguise, ST only marketed the clocks and married the Hermle movements to its home clock case.

The first step in replacing a Seth Thomas clock movement is to get the numbers off of the back plate of the movement. If it starts with an A like A401-003 this is the ST number and must be converted with the chart. Find the number in the list and get the new number, and write this number down. After writing the number down click that converted number to get to the section where that movement resides on this website. It will ask you for the options you need, and this is when you refer to the number you wrote and get that same movement.

The above instructions work in a perfect world, but you know how it is. This chart unfortunately is often wrong and is only used as a basic guide to what series the movement is only. The rest of the attributes it is best to check such as CM lengths and hand shaft lengths, and email us with this information to we can verify the charts accuracy. Our email address is [email protected] and we would love to help.

Even doing the conversion leg work, it is far better to do this and get the new movement instead of repairing the old. Even just having a German Seth Thomas clock movement means the clock is over 40 years old to begin with. These are 25-30 year movements and then they are just trouble. The new movement will ship fast, be easy to install, less money than an overhaul, and be ticking in the fastest method.

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New Seth Thomas Clockworks - Why Order

A New Seth Thomas Clockworks equivalent replacement can ship the same day you order it, usually from of Huntington, MA via UPS. The new movement (if available) will cost less than a cleaning and overhaul of the old unit, will last much longer before having to worry about it again and will be up and running in your clock in a week or two rather than months down the road as in a repair. What is being offered is the same movement you have now but new, it is not some knock off replacement, it is the same movement. The modern Seth Thomas clocks were produced by manufacturers other than Seth Thomas. It will have their name on the movement to say that they designed the clock and its case, but they did not make the movement if the clock was produced in modern times (post 1950).

It is a simple and obvious fact the new one is better than chasing the old one. With the cost savings and life expectancy tripled its an easy choice. When the Seth Thomas clock is made prior to the end of WW2 its a different story. Those are no longer made but you can send us the movement only, we do the best restoration.

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Seth Thomas Clock Not Running

Seth Thomas Clock Not Running is from a lot of factors, but the most obvious is age. The life expectancy of these units is 25-30 years. After 25-30 it is decision time. There are two choices if saving the clock, restore the old movement or get a new one if possible. The choice is an obvious one, the new unit costs a fraction of the price of restoration. It ships today instead of waiting up to 6 months for the restoration to be completed. A new one will last another 30 yrs without much complaint.

Why does age effect the operation of the clock movement? The clock oil that is put on the movement back when it was new, has solidified with age. What was once a lubrication to the clock movement has now turned to a sticky black abrasive substance and creates both resistance and wear on the movement. This wear and resistance will ultimately stop the clock from functioning properly because the pivots that ride in the holes of the movement's brass plates will not be able to spin as freely as they did in the past. The holes have become oblong instead of round so the pivot is pinched inside of the hole that it's supposed to spin inside of, and the oil is an abrasive rather than a lubricant.

So now you see the choice is pretty clear. The new movement, when available is the best choice by far. The movement will be the same movement for a fraction of the price, brand new, oiled, tested, and last decades longer than even the best restoration.

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Seth Thomas Historical Timeline

Seth Thomas Historical Timeline reveals a long history of clock making. The company was exchanged from one company to the next through the years, and is now extinct.


Seth Thomas starts in Wolcott, Ct by James Thomas.


James Thomas begins working with Eli Terry as a clockmaker apprentice near Waterbury, CT. Because Terry got an order to make 4,000 clocks.


James Thomas opens his own Seth Thomas shop in Plymouth Hollow, CT.


Seth Thomas starts using brass clock movements which they used in Ogee Clocks.


Seth Thomas Clock Company is incorporated


Death of Seth Thomas, now run by his three sons, Seth Thomas, Jr., Aaron, and Edward.


The town of Plymouth Hollow changes its name to Thomaston in honor of Seth Thomas


Seth Thomas Watch Company is established


Seth Thomas Clock Company becomes part of The General Time Instrument Company by the great grandson of Seth Thomas


The Thomas family no longer controls The General Time Instrument Company


Seth Thomas Clock Company becomes part of General Time


General Time becomes part of Talley Industries


General Time ends and Colibri buys the assets of Seth Thomas


Colibri Group discontinues all business with clocks

End of Seth Thomas Historical Timeline

As you can see, the Seth Thomas Clock Company had a long run and a wild ride. The company name may now be found on silly things like lighters and some quartz clock dials. What we offer and sell is the German ST units made in Germany. These are the units General Time and Tally Industries sold under the Seth Thomas name they owned, and put Hermle clock movements in the clock cases. These German units are high quality and last 25-30 without much complaint.

- - The content of this web page and web site was written and copyright by James Stoudenmire of - It may not be used commercially without permission. - -

Seth Thomas Logo

Seth Thomas Clock Movement OLD Number / NEW Movement Number
Please note, this list is often WRONG and is only a basic guide.

  • * Rear Pendulum Seth Thomas clock
  • ** Front or Rear Pendulum Seth Thomas clock
  • *** Needs new pendulum with it. Need to reverse direction of chimeblock.