Expert: Martin Meyer - 4/9/2009

Question
A lot of clock parts stores on the net . Could you tell me which ones you would recommend for the best selection of small brass gears. I need an eight tooth square hole outside around the size od a dime. I dont think I will find the exact size, but with a fair selection I think I will be able to hand finish one close to what I need.
Thank You
Leo in NM

Answer
Hi Leo,

The major clock supply houses like Timesavers (www.timesavers.com), Merritts Antiques (www.merritts.com), Empire Clock or Black Forest Imports all carry similar selections of gears. However, they only carry certain commonly replaced specific-purpose gears, no assortments of generic gears in various sizes. It is a considerable disadvantage in answering your question that you don't indicate what clock you are working on, or what gear you need to replace. If you indicated "ratchet wheel", "escape wheel", "center pinion", etc., I might be more able to provide assistance.

In clocks, a gear is not just a gear. The number of teeth, type of teeth (epicycloidal or involute), function (ratchet, escape, pinion, etc.), exact size including thickness, all are essential parts of gear selection. As far as modifying a gear, this is rarely possible. If the pitch circle (spacing of teeth) is not exactly compatible with the gear or pinion which the gear will mesh with, the two may turn through a couple teeth, but will soon jam.

Finally, a dime-sized gear with only 8 teeth and a square hole sounds like it might be a stopworks gear. If it is, please get back to me and I may be able to assist you.  http://www.clockmasteronline.com