Watch Running Slow - Solved

[cdjswiss]

Some of you may remember the little tool that I made that enabled be to screw in the mean-time screws of an IWC Cal 64T movement that was losing 10 minutes per day. Well with the screws fully in (3 turns per screw) the movement was still running very slow. After more cleaning of the hairspring and undercutting a pair of balance screws by the amount that corresponded  to the thickness of a timing washer that would produce a change of 5 minutes per day (when added) ... it was still running slow by 5 minutes per day.

 

Back to shoveling snow and wondering if I should simply remove two balance screws, then enlightenment. The canon pinion might be slipping. With a tightened canon pinion the movement now runs fast, and with a pair of normal length balance screws to replace the undercut ones I am within the range of the regulator.

 

My theory is that because of a stiff spot during the hour wheel turn the canon pinion slipped just a little every hour and this could explain why the regular loss of 10 then 5 minutes per day was so reproducible. Any better explanation?

[bobm12]

Hi colin,

 

Good to see you back. I find your reasoning very accurate, in fact, I've seen many a watch here treated the same way: tightening the canon pinion and voila, problem solved.

 

In my case, it has always been the hairspring but as a beginner I tended to fiddle too much with the balance and that would deform the hairspring just enough for the problem to happen. Since I'm better at it now I haven't encountered the problem anymore.

 

Cheers,

 

Bob

[Geo]

My theory is that because of a stiff spot during the hour wheel turn the canon pinion slipped just a little every hour and this could explain why the regular loss of 10 then 5 minutes per day was so reproducible. Any better explanation?

Hi Colin, good to hear from you again.

Regarding the issue with IWC, your successful resolution of the problem, your analysis seems highly probable. Well done sir! :)

[daz]

Hi Guys

Sorry to jump in here

I have just been asked to look at a watch that has great sentimental value to its owner that is also has a similar problem, the watch works fine and is ticking away but the minute hand barely moves and he says it can take about 15-30mins for it to move but it still moves slow I do not know about the hr hand so I suspect a slipping cannon pinion and was wondering if they can be tightened in situ or do they need to be pulled and then tightened using a broach. I have already ordered the Bergeon tightener as I believe it will come in handy for other projects...

Cheers

Darren

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[Geo]

You will have to pull it Darren. You will only need to broach it if you over tighten it, remember a little goes a long way when it come to tightening.

[daz]

Many Thanks George

 

I thought as much, so it's just a case of lifting the dial and hr wheel taking off the cannon pinion and tightening up at it's base and refit

as I am a bit reluctant to take it fully apart with it being sentimental and the fact that I won't know what other problems I will run into

should I go down that route...

 

Many Thanks George Greatly Appreciated!!

 

 

Best Wishes

 

Darren

[Geo]

Hi Darren, take care when you tighten it. You should compress it about halfway down the pinion and insert a smoothing broach to make sure you don't squeeze it too far. I was thinking about cutting broach in the earlier thread.

Have a read of this thread :- http://www.watchrepairtalk.com/topic/1501-as-1882/?hl=%2Btightening+%2Bcannon+%2Bpinion#entry14522

[daz]

Cheers George,

 

You are indeed a fountain of knowledge my friend.. I will give it a go

 

Many Thanks

 

Darren :thumbsu: 

[Geo]

I don't know about that Darren, I just like helping when I can. :)

[Blacklab]

Just done one with a pair of small & slightly blunt wire cutters supported with one of the wife's clothes pins, a very gentle nip & its worked a treat. Some swear by nail cutters.

[daz]

I looked at the nail cutter option but I thought with my big hands it would soon be through :) ,so I thought I would invest in the Bergeon set 

they are currently stuck at PO till tomorrow .. would a pin vise be any good do you think??

[Blacklab]

I don't think a pin vice would give much of an indentation, if any. With a needle or pin (whichever fits best) inserted you would have to go some to cut through, it only requires very little pressure on the cutter. If in doubt try to cut a needle with cutters - you will have to exert a fair amount of pressure as they are normally made of hardened steel.

[CKelly]

Hi,

   I thought I would jump in here with a word of caution. Some cannon pinions are very brittle, especially some Zodiac watches and can actually break so be careful. The tool I normally use is the fingernail cutters however I have filed small triangular notches into the top blade. That way you can have compression on three points rather than two. Also if you haven't tightened one before be aware that there are areas on the cannon pinion where tightening will and won't work.

Charles K

[daz]

Many Thanks Blacklab and Charles

It is greatly appreciated..

Best wishes

Darren

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[WillFly]

Some movements are prone to cannon pinion problems - the part is a weak point in the design. I've found this to be the case with early Wittnauers, and have had two which snapped with the slightest pressure on them. All further complicated by the difficulty of obtaining replacement parts for that particular make.

[daz]

Yes that can be a problem Will along with how much it will cost as well. So I think very gently does it will be my main thought..

Thanks Will

Best wishes

Darren

[CKelly]

Hi,

   Will touched on an issue with some cannon pinions that I mentioned in my reply earlier. Some cannon pinions are prone to breaking when tightened and are also prone to becoming loose. Some Wittnauers and especially the Zodiac sst movements have these issues. I fixed a Zodiac for my grandson that ran perfectly except that the hands would not move. I was afraid to try to tighten the cannon pinion and thought that since they were prone to becoming loose that a donor movement was not a good solution. After thinking about it for some time finally decided the only solution for me was to add some material to the inside of the cannon pinion. What I did was take a hot melt impregnated nylon string and trim it down and inserted it into the cannon pinion. Eventually by trial and error I got it so that it was loose enough to allow the watch to be set but still had enough friction to allow the hands to be driven by the movement, Watch will now run, keep time and the date will change and has been doing this for about two years.

   I know purist may be gritting their teeth right now over my solution but I came up with it after searching many Zodiac forums and reading about this problem that seemed to have no easy solution. My solution has worked and did no harm that I can see to the watch.

 

Charles K

[Geo]

Good result Charles!

I would have been inclined to anneal the pinion then compress it. Due to is taking virtually no load, I would have put it back in the watch in the annealed state. When you consider that it is driving a couple of lightweight brass wheels, I'm sure it would be fine.

[cdjswiss]

I looked at the nail cutter option but I thought with my big hands it would soon be through :) ,so I thought I would invest in the Bergeon set 

they are currently stuck at PO till tomorrow .. would a pin vise be any good do you think??

Beware, as others have said.

When tightening the canon pinion of my IWC Cal 64T using the Bergeon tool, the first attempt seemed to be OK , but as I replaced it onto the centre wheel top pivot it broke into two pieces. The metal is hard and the Bergeon tool tries to make a dimple into the pinion but in my case it created a fracture line!

Fortunately I had a spare centre wheel and canon pinion and these were used to fix the problem.

[daz]

Many Thanks cdjswiss

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[daz]

Many Thanks for the advice cdjswiss it is much appreciated

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