I have been working on a Hamilton 914 and the cannon pinion is loose. The hands do set and the movement runs but the minute hand will advance just a tiny bit then stops. The movement continues to run fine. How can the pinion be tightened? If that is the problem. Thanks for any help. Paul

I had this problem on a Waltham, and found this post by Roger Nolfe that tells how to tighten it. This thread also has a lot of good info, including pictures, on tightening canon pinions.

Paul, your description confirms a loose Hamilton Cannon pinion. The thread Jim refers to shows some ways to address it. Great care is necessary and the failure rate* is so unpredictable that all any of us can say it "try and hope".

*The hardening process for these little parts is so critical that some end up "Glass Hard" and will break unless "softened" before any attempt to tighten them. You can tell the hardness by the sound of the "Tic" (too hard) or "Toc" (probably OK) when you first tap the tightening tool. Most of us have learned from (broken pinions) "experience".

Jim, Thanks for the helpful thread info.

Dave: Not sure which way to turn now. I tried to remove it for a thorough cleaning but was unsucessful. I think that my attempt to remove it loosened it up just enough so the hands will not turn. What type of tool is used to remove it? I don't want to bend the center wheel and from what i see it has to be removed in order to tighten it. Looks as though i might be looking to buy more tools.

Paul

Paul, first, do not "pry" it up because you are sure to break some of the "leafs" (Teeth) of the Cannon Pinion. It sounds like you may have jacked up the cannon pinion when removing the hands which sometimes "cock's" it slightly. Try pushing it back down flush to the dial plate and then see if you can "tweezer" it up. NO PLIERS! If it resists, one of us can help. I would do it if you send it to me.

Dave: It seems quite flust to the plate. I did use a set of hand removers to get the hands off, but i might have bent something. Is trying to tweezer it up while turning the setting mechanism ok? Paul

No

I always use a cannon pinion removing tool. A friend broke 3 center wheels pinions before taking my advise to buy one. This is one tool that I say is a must.