Expert: Michael Radi - 11/9/2008

Question
This clock was given to me.  It looses about 1 minute per day. I have the key. How do I know how much to wind and how do I get it to not loose time?

Answer
Spring wind clocks will run faster when they are freshly wound, they will be pretty steady through the middle of the run and slow down near the end. First, wind the clock all the way up. It may be slowing down because you are near the end of the wind.
It is a misnomer that a clock becomes over-wound. If a clock stops because it has been wound all the way up, it is because the clock is not properly lubricated or has other problems. A clock in good running condition can be wound until the key will go no further and run without any trouble.
Adjusting the time keeping:
If the clock has a pendulum, the timing adjustment is in the pendulum length. There will be a small nut under the pendulum bob. Turning that nut to the right will push the bob up, causing the clock to run faster. Turning it to the left will do the opposite. The nut has "right handed" threads. If you were to look at the pendulum up from the bottom you would turn the nut clockwise to move the pendulum bob upwards and cause the clock to run faster. One minute per day is pretty close for a mechanical clock, I would turn the nut about 1/2 turn to start. Then run the clock for a day and check the timing keeping.

Some notes:
Some clocks have a pendulum lock, usually a screw going through the pendulum bob, straight into the rod. This is typical in French clocks and probably doesn't apply to yours. However, if there is a screw locking the pendulum bob to the rod, you must loosen that screw before making adjustments.