16-Point Check (Bulova 11AOCD)

WP_20141112_12_51_16_ProNext up in my 16-Point Check project was this beauty (well, I could do without the band, but the Tiger’s Eye dial was pretty nice). I lucked out with this one in that besides being dirty and having an irregular beat, there wasn’t really anything wrong with the watch. Well, at least until I pulled the movement out of the watch.

WP_20141112_13_32_48_ProSo, I was a bit thrown off. The bridge over the cannon pinion? Not something you see all the time, but not too unusual. You see the little lever that is at the left? I was confused. I pulled and pushed on the crown a bit to watch if it interacted with anything and saw that it was moving a little wheel. I went ahead and stripped off the set lever bridge to get a better view.

WP_20141112_15_45_48_ProIt was some kind of jumping mechanism, but I couldn’t, for the life of me, figure out what it was for. There wasn’t anything on the top plate that it attached to (which makes sense because the wheel the lever interacted with wasn’t long enough to interact with anything), but clearly the arm that was coming off of the set-lever interacted with the wheel when the crown was pulled out a bit further past the setting position. My mind went two places: some kind of proto-hacking seconds feature (some watches, when the crown gets pulled out to the setting position, the second hand stops-it’s referred to as a hacking mechanism), or perhaps something to do with a calendar function. I went ahead and continued on with the tear-down and decided I would ask Mr. Poye about it later.

off center pinionIgnoring the fact that the bridge was magically put back on from the last picture, I want to draw your attention to another feature of the watch that struck me as odd. The cannon pinion itself wasn’t friction fit like most cannon pinions, plus it had a wheel that was held down by the bridge as well as in place with a spring (the spring should be under the wheel, not half under/over). That wheel interacts with the pinion of the center wheel.

I did have a small issue when I was working on the watch. The shock spring on the bottom plate gave me a heck of a time. The first time I went to open it, it came unhooked and bent, so Mr. Poye had to replace it. The second time I tried to work with it (after I was ready to redo the oiling on it), the spring came out again. What was odd to me was the shock springs were the same for the upper and lower jewel and I had no issue removing the upper jewel (and followed the same procedure for both, it’s just that the lower spring setting decided to be annoying).

After running the timing tape, I took it up to Mr. Poye to get a suggestion as to why it was looking kind of weird, and he asked me if I had oiled the cannon pinion. I had told him that I hadn’t because I had yet to put it on. It was at that point that he explained to me that the watch I was working on had what was considered an off-center cannon pinion/center-wheel. I didn’t take a picture of the wheels, but I was able to find a tech guide online, so here is a picture from it

cannon pinion

As you can see, the center wheel has a cannon pinion that sits on the center wheel. It is friction fit on the wheel, but it needs to be oiled. Mr. Poye showed me how to separate it and he used some D5 lubrication, which when I asked if it was a grease or an oil, he replied “yes.”  It is a thick oil or thin grease that can handle different conditions. I also took the time to talk with Mr. Poye about the weird part that was on the movement and he let me know that the movement was able to take a couple extra parts and have a calendar function added to it. That makes sense because there looked like there were a couple “empty” spots on the bottom plate that looked like they could have some parts that I’ve seen in calendar watches. After my mini-lesson and the oiling that Mr. Poye did on my cannon pinion, I went ahead and re-timed the watch and was very pleased with the results:



Prior Entries in the 16-Point Check Project


3 responses to “16-Point Check (Bulova 11AOCD)

  1. Pingback: 16-Point Check (Seiko 11A, #2) | watchmaking journey·

  2. Pingback: 16-Point Check (Arnex/Parrenin 40) | watchmaking journey·

  3. Pingback: 16-Point Check (ETA 2660) | watchmaking journey·

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