I just got a 105 Hampden in the mail today. I wind it and it runs -- makes a nice ticking sound and the second moves (of course all the wheels seem to be going around). I set the lever set hands - no clearance problems there. I put the bezel back on and the hour and minute never move. I check the lever and it seems to be in (dial still on) and the second hand just chugs along but not the hour and minute. Hands seem tight and move properly when setting. I will open this up and find the answer to the mystery (i think i know the answer, but I would like to hear other opinions) and I don't think it was the butler in the palor with a gun. thanks, mike paynter

Maybe a really loose cannon pinion?

Aaron

Mike,

Without looking under the dial, I would agree with Aaron. The only thing that doesn't equate is the bezel being installed or not. If the cannon pinion is loose and the minute hand drags against the crystal, that would make some sense.

One sympthom of a loose cannon pinion is little to no resistance during setting of the watch. This is caused by insufficient friction between the cannon pin and the center wheel arbor.

John D. Duvall
Vice President, Education

There aren't many problems that can cause the symptoms Mike describes above, and as everyone else has already suggested, the primary one is a loose cannon pinion.

A similar problem, however, can result when an hour wheel is frozen (or badly gummed-up) on the cannon pinion, or when a minute pinion is gummed-up and stuck to the plate. In such instances, the setting resistance may feel normal, or even tight, but the cannon pinion will slip on the center staff before sufficient torque can be transmitted to turn the motion work. In Mike's case, since he describes: "Hands seem tight and move properly when setting," I'm going to bet that's the problem.

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Steve Maddox
Past President, NAWCC Chapter #62
North Little Rock, Arkansas
IHC Charter Member 49

Steve,

If the hour wheel is frozen to the cannon pinion, wouldn't the hour and minute hand move at the same rate during setting?

Also, since the minute wheel teeth engage the cannon pinion and the hour wheel teeth engage the minute wheel pinion, wouldn't that prevent you from setting the hands at all if the hour wheel was frozen to the cannon pinion?

If the hour wheel is frozen to the cannon pinion and friction was still available between the cannon pinion and the center wheel arbor, wouldn't that also stop the movement from running?

John D. Duvall
Vice President, Education

John writes: "If the hour wheel is frozen to the cannon pinion, wouldn't the hour and minute hand move at the same rate during setting?"

No. The engagement of the hour wheel teeth with the minute pinion would prevent the hour wheel from moving at the same rate as the minute hand, unless the teeth on the minute pinion or the hour wheel were stripped.

"Also, since the minute wheel teeth engage the cannon pinion and the hour wheel teeth engage the minute wheel pinion, wouldn't that prevent you from setting the hands at all if the hour wheel was frozen to the cannon pinion?"

Yes, if the hour wheel was completely "frozen." If it was just partially frozen (or really stiff -- however one wishes to describe that), the result would be as suggested above. Hand setting would be "stiff," but possible, and the cannon pinion would slip while the movement ran, provided the movement had sufficient torque to continue running. Remember, when the setting mechanism is engaged, there's a "direct drive" between the crown and the motion work, and if the crown is turned hard enough, something has to either move or break. The same isn't true with the center wheel; if the movement has sufficient torque to run, the center staff can slip in the cannon pinion, even if the motion work is locked up.

"If the hour wheel is frozen to the cannon pinion and friction was still available between the cannon pinion and the center wheel arbor, wouldn't that also stop the movement from running?"

It depends on how tight the cannon pinion is, and how much torque the movement can provide. Obviously, an 18s movement with a good strong mainspring, will provide several times as much torque as a wristwatch movement, etc. In general, torque is a product of overall size, with large watches producing the most, and small watches producing (and requiring) the least. If a particular movement can provide more torque than is required for the cannon pinion to slip, the movement will run while the cannon pinion slips. Conversely, if the torque required to slip the cannon pinion is greater than the movement can provide, the movement won't run.

A few months ago, I bought an 18s Bunn Special at an estate auction. It had a yellowed cellophane crystal which had caused the hands to rust, and the cannon pinion and hour wheel were frozen together (and still are -- I haven't had time to work on it). That particular watch will run when wound, although the hour and minute hand do not advance, and when the setting mechanism is engaged, the resistance is such that I think gears would strip before the hour wheel and cannon pinion released their "death grip" on each other. In order to repair that particular watch, I suspect I'll have to remove the hands, then the dial, and then remove the hour wheel and cannon pinion as a "unit." I'll then have to fit the cannon pinion teeth into a hole of the appropriate size on a staking tool anvil, and use a stake to drive the cannon pinion down, and out of the hour wheel. Of course, once the two parts are separated, the rest is gravy........

On a somewhat related note, Bulova Accutrons are notorious for producing huge amounts of torque -- so much in fact that it's detrimental to them in the long run. The motion work in Accutrons rotates around a stationary stud in the pillar plate, and for some reason, many watchmakers apparently didn't realize that the stud needs to be lubricated! The result is that after years of operation, the cannon pinion will eventually seize on the center stud, with the result being that the hour and minute hands stop advancing, while the second hand continues to move normally. It's a common problem with Accutrons, and occasionally the center stud is so damaged that it must be replaced.

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SM

Steve Maddox
Past President, NAWCC Chapter #62
North Little Rock, Arkansas
IHC Charter Member 49

Steve,

Thanks for clarifying "frozen". When dealing with things mechanical, I interpreted it as something immovable or seized.

John D. Duvall
Vice President, Education

John,

You weren't wrong in your interpretation, I just badly described what I was trying to say.....

In my initial reply above, I wrote: "frozen (or badly gummed-up)," which was intended to show that I didn't mean entirely frozen or seized, but only something approaching that. I'm sorry I wasn't able to describe the situation more clearly.

For future reference, what would be a good way of describing something that's much stiffer than normal, and well on the way to being "frozen" or "seized," but not quite to that point? I tried to think of a neat, concise way of describing that situation, and my communication skills obviously failed me.

If anyone has any suggestions, they'll be greatly appreciated, and I'll try to use them in the future!

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SM

Steve,

Trust me, I know what you mean! I thought about using the term "binding" but that could also be construed as frozen or seized. How about excessive friction?

When I was an instructor in the USAF, I was teaching the environmental control system on the F-5E fighter to some Saudi Air Force students. During a discussion on a temp sensor, I stated "when the temperature goes up", all of the students looked toward the ceiling of the classroom. I should have said "when the temperature increases".

John D. Duvall
Vice President, Education

I am not sure exactly what caused the problem but this is what I did to this crazy watch. I think Steve had the real answer with this statement: "The result is that after years of operation, the cannon pinion will eventually seize on the center stud, with the result being that the hour and minute hands stop advancing, while the second hand continues to move normally." I took the dial off and the hour wheel and minute wheel seemed normal (was not expecting this - thought someone used the wrong parts)nothing tight or loose. Then I tried to take the cannon pinion off. Now I have a lite touch and I have never broken anything (knock on wood)with too much pressure. But I was afraid this would be my first. With slow force the cannon pinion came off and the center wheel was not destroyed. I was not about to use this cannon pinion again and I just replaced it with another which was snug but normal. Since I thought this might be my problem I did not touch anything else in this 105 Hampden for now. For those who might have tried something else also, in science we never change more than on thing at a time. This is called the scientific principal. (when not baking in my bakery or fixing watches, I teach Algebra in Night School). The watch went in my pocket and after 24 hours, it seems to keep railroad time like it should. I think Steve deserves a prize. If he ever gets to Canton, O as in home of Dueber Hampden, my treat to one of my World Famous Key Lime Pies (Pres. Bush 41 was one of my customers when he was on vacation - I used to be in the Florida Keys). Mike Paynter

So, What was it? Loose or sticking (seized)?

Aaron

The cannon pinion was almost welded to the center wheel. New cannon pinion, now the watch runs perfect. mike paynter

Steve to the rescue, again!

Mike,

Are you saying that the cannon pinion was fitting too tight on the center wheel arbor or did you mean to the hour wheel?

Where did Steve quote "The result is that after years of operation, the cannon pinion will eventually seize on the center stud, with the result being that the hour and minute hands stop advancing, while the second hand continues to move normally."

I just found where you quoted Steve but he was talking about Accutrons.

We would still like to know what was binding on your watch. Are you sure it wasn't the hour wheel binding with the cannon pinion?

John D. Duvall
Vice President, Education

[This message was edited by John D. Duvall on February 28, 2004 at 2:02.]

After removing the cannon pinion, I put a drop of oil on the center wheel (that what the cannon pinion goes on). I then put a new cannon pinion on the newly oiled shaft and nothing more. I used the same hour and minute wheel. I will say that the old minute hand could not be used, the cannon pinion was now slightly smaller and the minute hand was too loose. I really did not find anything unusual except the cannon pinion being almost welded. Except for removing hands, dial, hour wheel and cannon pinion, I did nothing else. Just reassembled in reverse order (one thing at a time). If I had done anything else , I would not have any idea which was the cure. mike paynter