Expert: Martin Meyer - 1/27/2010

Question
I have a old French pendulum clock which is causing me problems.  It will run for 2 0r 3 weeks perfectly, then will stop. I have replaced the pendulum as the one that came with it was just of chunk of lead. The fitting from the escapement & the crutch will slip and it gets out of "beat".  I just move the crutch slightly and everything is fine for a few weeks. It there any way to tighten the fitting from the escapement to the crutch?  
Thank you.
Dennis

Answer
Hi Dennis,

There is usually no separate fitting that connects the crutch wire to the verge arbor (shaft). Usually the crutch wire goes through a cross-cut hole in the verge arbor. It may be possible that yours mounts on a collar that is fastened around the diameter of the verge arbor.

The assembly from the verge to the crutch must be absolutely rigid. Also, if the verge arbor bearing holes are worn so that the verge bounces up and down as it contacts the escape wheel teeth, these bearings must be rebushed.

Not knowing exactly how your crutch attaches, I can't give you very specific advice. Whichever way the crutch attaches to the verge, the repair will involve re-riveting the loose part, and this is never a very easy job. Try to find the loose point and use watchmakers stakes (or modify small punches to suit the application) and a small brass hammer to tap the loose point, thus indenting the metal and holding the crutch wire tight again.

There are some very exotic new adhesives which may work for a while, but probably not be durable. Soft-soldering is also sometimes used, but the repair is rarely strong, and the parts must be absolutely cleaned of flux afterward or severe corrosion will result. Hard-soldering (silver brazing) is, of course, absolutely out of the question, as it will anneal both the brass and steel parts, making them uselessly soft.