Expert: Martin Meyer - 2/8/2008

Question
Hi Martin - I have a Gustav Becker Vienna serial number 68,177 which would date it about 1872. The clock is running slow and I have raised the bob up to a point that it indicates that the problem is else were. I have ulta sonically cleaned the works and reoiled. I have adjusted the beat so that it is also good. Outside of rebushing, is there anything else that I can do to adjust the speed. Like any wear in the slot of the pendellum. I noted adjustments on the escapement but have not done anything yet. Your advise is appreciated

Glenn

Answer
Hi Glenn,
    First, I'm wondering just how slow the clock is running in minutes per day; this could be a help in diagnosis. If the loss is large (30 minutes a day or so), it would indicate some larger problem, so I will assume that the loss is smaller, i.e. within the normal limits of regulation.
    The rate of a clock is theoretically determined solely by the length of the pendulum, so I would look at the entire pendulum assembly first. The most common cause of a clock running slow, but not stopping or running erratically, is that some original part has been replaced. The pendulum stick may not be original, the pendulum leader may not be original, the crutch (part coming out from the movement that passes through or around the pendulum leader) may be too loose or too tight on the leader (a drop of oil here is a good idea). The leader should have a small clearance from the crutch so that it doesn't rub against the crutch, but if the leader is bouncing from one side of the crutch slot to the other as it swings, the slot in the leader should be tightened to minimal clearance. I would also take a look at the suspension spring; it may have been replaced by a longer one, or it may have lost its "springiness." A stronger (thicker) suspension spring will make the clock run faster by a few minutes a day.
    If the pendulum swing is very weak, the clock may need rebushing, but in general, if the pendulum is swinging reliably the clock should keep time.
    Escapement issues are a possibility, but if the locking depth is too deep, the clock will stop, and if it is too shallow the escapement will allow several escape wheel teeth to pass at one time, so the clock will run fast.
    Another real possibiity is that the clock's mechanism is keeping time, but the clutch that holds the hands tight is slipping. If the hands move almost effortlessly when you turn the minute hand, this may be your problem.
    I can't really cover all the possibilities in this forum, so if you need additional information feel free to send me a follow up, or contact me directly at www.clockmasteronline.com .