Things not written in the books

Discuss clock projects, repair techniques; exchange tips and advice.

Things not written in the books

New postby Dick Feldman » Sun Mar 09, 2008 3:24 pm

Many things in clock repair are maybe not written in the “how to” books and really should be known. I would invite others to add to this thread.

Many times a clock will pass through the repair shop without consideration of the lowly clicks. The clicks and accompanying mechanism should be inspected at each service interval. Failure of a click can result in damage to the clock movement and injury to the person winding the clock. First inspection should be of the click itself. The click should have a distinct contact point with the ratchet wheel. Inspect the end of the click to be sure it has not been eroded and will make proper contact with every tooth of the ratchet. The click rivet should be checked. If the rivet or the pivot hole in the click is loose, the click could wander and miss. The click return spring and the material it is made of is important. Brass is not a good material for springs. With age, brass will become brittle and break. Brass also has a tendency to fatigue. Click springs should be fashioned from spring steel as this is a more dependable material. Lastly, every tooth of the ratchet wheel should be examined. Failure here can be from a rounded over or malformed tooth and looseness. Check the center of the ratchet wheel to make sure it is tight on the arbor and running true.
Failure of any part of the click assembly and the rapid release of power from the drive weight or spring can result in bending of arbors (usually on the second wheel), damaged main springs, bending or breaking of teeth in the lower part of the train, damage to the drive weights or main springs. With the rapid release of power, the clock case may be damaged. Every part of the click assembly must operate every time.
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Re: Things not written in the books

New postby Tony Ambruso » Fri Mar 28, 2008 2:54 pm

I first came across a discussion of this on the NAWCC Message Board. I had never read anything in books or heard anything about this in workshops: checking the bushings on tall case cable pulley wheels. Since becoming aware of potential wear problems with the bushings in that pulley wheel, I have made it a point to inspect them when doing overhauls. I have also found a significant number of them to be mildly to severely worn in the majority of situations. I haven't kept accurate statistics, but I have found the problem in over 50% of the cable pulley wheels inspected.

I rebush "pulley wheel strap" just as I would a clock plate. I use my bushing tool, and I have the larger sized reamers for jobs like these. You have to be inventive in securing the work in a bushing tool because you are working so close to the end of the piece. I use one of those stepped staking blocks for escape wheels to keep both sides of the strap centered. It's not an exact science, a reasonably centered pair of bushings will be enough to obtain acceptable results. I have read about some people using a lathe, but I haven't found that to be necessary. I haven't seen any of these pulley wheel parts being available for sale separately.

I have attached a picture of a pulley wheel strap that has the obvious problem.
DSCN5232.JPG
worn bushings pulley wheel attachment
DSCN5232.JPG (72.08 KiB) Viewed 1077 times
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