Expert: Martin Meyer - 5/30/2009

Question
My wall clock does not strike on the half hour. I hear the click showing it wants to chime but does not. It does strike on the hour correctly. Is this something I can fix?

Answer
Hi Robert,

There are two types of striking mechanisms, the "count wheel", found on some antique clocks, and the "rack and snail", found on both antique and modern clocks. I don't know which one your clock has, so I can only answer generally.

It would be quite unusual for a rack and snail to strike on the hour, but not on the half; if it had a strike problem, it would more likely not strike at all. If this type of mechanism had this problem, I would have to examine the clock to even make a guess as to the cause.

The count wheel mechanism can only fail to strike on the half while it does strike on the hour if it has a separate mechanism for the half hour strike. This is most often seen in antique clocks which strike the hours on a coil gong, but strike the halfs on a bell. In this case, you could remove the hands and dial and look at the movement to find the bell and the hammer which strikes against it. This will be a different hammer from the one that strikes the coil gong. First, check to see if the hammer is simply adjusted too far from the bell to strike it. You can bend the hammer wire so that its at-rest position is 1/16" to 1/8" from the bell to solve this problem. If the hammer is not lifting and falling at all on the half, the hammer tail (part mounted on the same shaft as the hammer, inside the movement which causes the hammer to lift) is probably out of adjustment so that the lifting piece on the center shaft (shaft with the hands on it) is not contacting it at all. You can try to adjust the hammer tail to contact the lifting piece, but this is a very delicate adjustment, and you may run into trouble. In this case, I would recommend having a professional clock repairer do the adjustment instead.  http://www.clockmasteronline.com