Clock keeps stopping

QuestionEdit

Hi John, I have a purchased a wooden cased mantle clock with a Perivale movement, the suspension spring for the pendulum was broken and part of it was missing. I purchased 3 different lengths from a supplier as I do not know the original length.I have tried the new ones but the clock will not keep running. It tick tocks for about 10 seconds then stops. I have removed the mechanism from the case to see if there are any other broken parts but I can not see any.Should there be any additional springs on the pendulum mechanism to assist with the swing? I would love to get it working as the clock is very nice and has a lovely chime. Any help would be appreciated. Kind regards, Chris

AnswerEdit

Chris, evidently the ss (suspension spring) is probably not the problem. However, you must have the correct suspension spring for it to run at the proper rate. A ss that is too thin will allow the pendulum to swing further than normal and the time between the oscillations will increase, causing the clock to run slower. If the spring is too thick it will decrease he swing and cause it to run faster. If it is excessively thick, it possibly will stop the clock. The characteristics of the ss have to be fairly to the originally specified unit. Do you know if the clock ran before you purchased it? Below is an excerpt from my instruction on diagnosing a clock that is not running:

For Mantel Clocks: The clock should be stable and not wobble or rock. When the pendulum swings, it should be "in beat", meaning that when the pendulum swings you hear an even tick....tock....tick....tock. If it is uneven, like tick..tock......tick..tock, the clock will probably stop. If it is out of beat, there should be an adjustment to set this. However, there is an easy way to correct this if the out-of-beat is not too excessive. You can shim up one side of the clock or the other to obtain the even beat. This method works if it isn't too bad. If it is excessive, other adjustments have to be made. If this doesn't do it there could be quite a few other causes such as old and gummy lubricants and/or worn parts that aren't visible from outside observations. It might need to be looked at by an experienced clockmaker. Let me know what you find.