I bought a grandfather clock and I am trying to figure out how to get it working (seems in good condition).
Is there a SE site for this?
I'd say the closest one would be diy.se, though you would need to check their help center, to see what is and is not on topic.
There is currently no site for time pieces on SE. I actually made a proposal to encompass anything about time pieces a month or so back, but it was removed for "reasons of moderation" after about 3-4 days, even though there was some slight activity on it. If you make a proposal for this on Area 51, I'll follow it.