This may be a new guy question, but are there two types of gear trains in the 992Bs? I have a watch that has a fourth wheel that doesn't match the rest of the gear train, cosmetically. I've included a picture. The fourth wheel has a round top to the spokes, while the rest of the gear train is flat on both sides. I couldn't keep the watch running, until I finally substituted another fourth wheel that was flat on both sides matching the rest of the gear train and now it runs without a hitch. I think I see a difference in the teeth, but I'm not sure. Could someone enlighten me on the subject? Thanks.

You are right John, this is a question that has been asked and answered MANY times in the past. The round spokes are a result of a casting used to make the 4th or center wheel.

The first 992B center wheels were cast, gold-plated and highly polished to give them the look of a solid gold center wheel. Around movement number C118000, the gold plating was dropped and later so were the castings, so the center wheels were stamped out of flat stock like the other train gears. This results in a rectangular spoke cross section.

Next time please try the find-or-search function before asking questions.

Sorry Ed,

I tried a search and didn't hit anything. Must not have used the right words. Thanks for the help.

John

John,

I give you credit for trying, but you probably were too specific in your search terms. Here's what I got searching on "992B center wheel" from the main page, which contains the answers to all your questions:

Search Results

Using search terms that are too specific is a common newbie mistake. Over the years terminology undergoes subtle changes and different people use different terms to describe the same thing, so you'll have better results if you keep your searches to a slightly more general topic area than the exact detail you are looking for.

You'll have to sift through more replies this way, but the key information you are looking for is much more likely to be there.

John don't feel bad. When I started searching my results would not turn up anything and I got the same help as you just got. My searches still are not as good as these old pros but they are getting better.

Good luck,
Harry