Hairspring adjustment

[chezwilly]

Hello,
I have a mantle clock with a hairspring. The clock is running fast and the lever on the hairspring is adjusted as far as possible to the slow side. Does anybody have any ssuggestions on how to slow this clock down?
Thank you.
Chez-willy

[harold bain]

chezwilly, this problem is usually the result of a loss of power. Cleaning and checking (replacing if needed) bushings on the clock movement will often fix this problem, by giving the balance wheel a more healthy kick.

[chezwilly]

Thank you, but I failed to mention that the clock had a complete overhaul and repairs were made as necessary.
Willy

[harold bain]

If there is any extra hairspring past the pin, you could try lengthening it. First check that the coils don't touch, and no oil is on them.

[shutterbug]

The thing is that the clock used to run with the spring as is, and probably in a near center position. If it doesn't now, something is wrong. I think you need to take it apart again, check all pivots and holes and make sure everything is easy to move. Oiled were needed, and dry everywhere else. Trying to find a band-aid might come back to bite you later

[bangster]

Shut's right. Lengthening the hairspring should be a last resort. Look for the power-robber. Friction somewhere? Slightly bent pivot? Maybe even a tired mainspring. Check the balance-staff cups (or jewels) to make sure they're not gummed up with misplaced oil, causing drag.

bangster

[harold bain]

If the clock was overhauled, as Chez said, the hairspring/balancewheel would have been removed for cleaning. It may not have been repinned in the same position.

[bangster]

Originally Posted by harold bain

If the clock was overhauled, as Chez said, the hairspring/balancewheel would have been removed for cleaning. It may not have been repinned in the same position.

Good point.

But shouldn't the repairman have checked the rate before returning it? I always do.