Expert: William J Perkins - 5/13/2009

Question
The subject clock runs fast, about 4 minutes every twelve hours. Which direction do I turn the adjustment screw in order to fix this problem. Perhaps I can wait for it to stop from running fast and then move the hand on the clock to the correct time.

Answer
I suspect you clock needs cleaning.  The deviation you note is rather large to correct by adjustment alone.  Even so, I suggest you try the adjustment route, you have nothing to lose.  To adjust the speed of the clock you must turn the rating nut, located at the bottom of the your pendulum bob.  Turning the nut counter clockwise will cause the bob to drop down, thus lengthening the pendulum, which causes the clock to slow down.  Turning the nut clockwise has the opposite effect, it will shorten the pendulum and cause the clock to speed up.  If this works for you, you might have to make quite a few adjustments before you hit the correct pendulum length.  Allow the clock to run at least 12 hours between adjustment.  Regards WJP