How to properly adjust a pendulum clock?

I've got a wind-up pendulum clock (says %26quot;Regulator%26quot; on the glass) that doesn't keep the right time. You can adjust the bob's distance by turning a nut. Does anyone know how to precisely synchronize these things or point me to instructions? There has to be a better way than trial-and-error.How to properly adjust a pendulum clock?I have no idea what the distance should be from the center of rotation to the center of mass of the bob, because that depends on how fast it's supposed to tick. Anyway, I don't think you need an absolute length to adjust to but a relative length change to use in adjusting. The period is roughly proportional to sqrt(length). So if the clock is running, say 1% slow, you need to shorten the distance by ~2%. (The square root of a value that changes slightly, by a factor of 1卤螖, is close to 1卤螖/2.) This is all %26quot;roughly%26quot; because the simple pendulum equation (period T = 2pi*sqrt(L/g)) assumes that all the moving mass is in the bob, with none on the shaft, whereas in real clocks this isn't true. The less true it is, the larger the distance adjustment you'll need to make.

I suggest you write down the changes you make (in fractions of a nut rotation) and the resulting change in time error. This should help you determine successive adjustment steps.How to properly adjust a pendulum clock?You want the length to be:



9.81/(4*pi^2) = 0.24849m = 24.849 cm