Expert: Martin Meyer - 7/19/2008

Question
Hello Martin, I have a Howard Miller wall clock, model on wooden case is 620-132, on rear of mechanism is 341-020A..31cm. When it is wound with the key the hands intermittently spin and the pendulum is eratic in movement and stops. I checked the pendulum fixing where it is attached to the rear of the clock and after removing two screws to look at the 'claw' I notice that the claw can move independant of the pivot pin..is this normal?? On the pivot pin where the claw is attached there is a spring tensioned between two small brass plates, sshould this claw be firmly attached to the pin to stop the brass wheel spinning when the pendulum swings??
Any advice would be much appreciated as this clock was a long service award.
Many thanks in anticipation. John.

Answer
Hi John,

There are a couple possible problems here. The hands may be spinning freely and quite fast whenever you start to turn the winding key; or, the hands may be running fast, but ticking off a one tick at a time. In either case, the problem is related to the verge or anchor, that is, the claw-shaped part to which you refer.

First, the verge should be mounted on its shaft with the clutch mechanism that you describe being quite tight, but movable if you push on it. If the verge is completely loose on the shaft, that is, the clutch is not holding at all, this is your problem. If the verge remains firmly in position, but can be moved when you push on it, the clutch is holding correctly. If the clutch is completely loose, the remedy is to replace the verge and its shaft entirely. Retightening it is not a workable solution. This part may be available from some clock supply houses, or you may have to find a clockmaker with the correct spare part.

Secondly, if the clutch is holding correctly, but the hands spin when you wind the clock, the problem is the "depthing" of the verge. This is a very precise adjustment of how deeply the verge pallets (the two tips of the verge) engage with the escape wheel. Unfortunately, this adjustment is set by the two screws which you removed when you removed the verge, so you have lost this adjustment.

Setting the verge to its correct depth is a technical operation that is beyond the scope of this forum to describe. However, a very abbreviated version is that the depth of the verge should allow one tooth of the escape wheel to release at a time, from the pallet on each side of the verge. The mounting piece that you removed when you removed the two screws has oblong holes in it, so that it can be set at higher or lower depths. If it is set too low, the verge will not release the escape wheel teeth on one or both pallets. If it is set slightly too high, the escape wheel will "flutter", that is, the verge will release several teeth at a time, and you will get the rapid ticking movement of the hands that I described in the first paragraph above. If the verge is set very much too high, the hands will spin completely freely, without any ticking motion at all. You may be able to reattach the verge and set its depth well enough that the clock will run reliably. If you are unable to do this, you will need to take the clock to a professional clock repairer, and he will be able to set the depth in precisely the correct position.  http://www.clockmasteronline.com