I picked up a nice Seth Thomas mantle clock over the weekend (don't ask me the movement, as I really don't know much about these clocks, other than I've always wanted one), and my question is this....

I DO know to regulate the speed of a clock, it's a matter of moving the pendulum up and down the rod, but what, exactly, does the regulator arbor on the face regulate? I know my key has two ends, one for winding clock and strike, but the other fits the arbor for 'slow' and 'fast'.

What does that do to speed up or slow down a clock?

Thanks for answering what I'm sure is a basic clock 101 question.

Regards! Mark

Mark, Sounds like you're describing a front dial adjustment that you would turn to raise or lower the suspension spring. Another way to raise and lower the pendulum.
Post a couple of pictures!

Thanks, Dave! I’ll try to shoot a couple shots today!

Regards! Mark