Seth Thomas pendulum problem

Posted: Sat Dec 06, 2008 5:15 am     Post subject: Seth Thomas pendulum problem

Hello
Wondering if anybody would know what weight needs to be used on a seth thomas 120 movement.
Below the No. 120 there is a no. 3 stamped into the plate. I thought this was the weight size. Apparently not. Put a 3 oz. weight on it and set it to the slowest setting(via key). the clock still gained like 20 min. every hour.

The clock was just cleaned and oiled. The verge seems to strike the escapment wheel okay. Has a new suspension spring in it(.oo3.5)
that is why i am thinking it is the wrong penulum weight.

Also, this is a short stroke movement(pendulum sways back and forth on a small arch)

Any information about this would be great. thanks[/b]

Posted: Sat Dec 06, 2008 2:04 pm     Post subject:

Sounds like you need an adjustable pendulum. You can buy these a supply houses like Merritts Antiques, Timesavers, etc.