You are here:

Antique Clocks/Clock maker marks


Hi Tom,
Do you know of a reference book that may show clock maker marks and date they may have used those marks?  We have several antique clocks and are trying to date them by the mark on the works but I can't seem to find much online.  For example our grandfather clock has Seth Thomas works.  It has ST in the diamond and circle.  Under that is says Made in USA.  Under that it says US America...

We would like to date several clocks from different American makers - not just the Seth Thomas.

Thanks for your time,

Merritts ( a number of reference books. To own them all would probably cost over $500., therefore, I have not invested in them.  There are two volumes dedicated to Seth Thomas alone. They have them for Gilbert, New Haven, Ansonia, Ingraham and others. The prices range from 50 to 75 dollars each.

Seth Thomas, Spartus and Westclox joined to become a part of General Time Corporation in the 1930's. As far as I know, General Time went bankrupt about 10-12 years ago, hence, I doubt they would provide much information regarding dating of older clocks.

My expertise is primarily in the repair of clocks as a hobby as well as a collection of clocks.

One milestone in the development of clocks was the rack and snail movement which automatically synchronizes the chime with the hands regardless how fast the hands are turned in the forward direction and in many cases allows the hands to be turned backwards. This happened about 100 years ago, although I have seen some relatively new clocks which did not have synchronized chimes.

If you are in the antique clock business you might want to consider some of these manuals. In thumbing through Merritts catalog I see they also have American clocks in three volumes. Again, in the 50 to 75 dollar price range. I would recommend accessing their website for this information.  

Antique Clocks

All Answers

Answers by Expert:

Ask Experts


Tom Williams


I can not think of any questions I cannot answer in regard to repairing antique clocks or radios. However, I am sure there are a few I have not heard and may not be able to answer. If I cannot, I will say so. I have been repairing them since I was a young child.


My experience includes repairing CooKoo clocks, Westminsters, BimBam, almost all antique clocks. I do a bit of repair on battery clocks where the value is sufficient to warrant working on them. I also repair antique (tube type) radios - all makes.

Indiana Historical Radio Society, Illinois Valley Antique Car Club, Military Vehicle Preservation Association

BEE from Cleveland State University

Awards and Honors
Four patents.

Past/Present Clients
Friends and family

©2017 All rights reserved.