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Deggsie

Correct method for increasing end-shake.

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Hello all. This is the first occasion I have had a need to increase end shake, but the escape wheel on my current project is being ‘clamped’ when the top and bottom end stones are installed. The type of end stones are as shown in the photo below:

8d77a786a38f2e6f794196260021acc1.jpg

The effect of the zero end-shake is that the watch will just about run at best or not at all. With the pallets removed the gear train runs like it’s been lubricated with tar.

 

I cannot imagine how incorrect assembly would decrease the end-shake, only increase it. So, my conclusion is that the escape wheel has been replaced at some time and not correctly fitted. What would you suggest as a best method to shorten the pivot please? We are talking just microns to prevent binding taking place

 

Thanks in advance

Deggsie

 

 

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First, are you sure that is the escape wheel binding? And that all pivots are straight? 

Shortening pivots is not just a non reversibile action, is also difficult to do precisely, for that reason is not recommended.

For a try, you can more easily shim the pallet cap stones with a tiny piece of aluminum foil. 

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how was it behaving before you dis-assembled it? if it was the same then it could be any number of things, wrong jewels replaced, wrong escape wheel, jewels inserted wrong, bent bridge etc. if it started after you touched it then it may be something you did, but just to understand it runs fine without cap jewels installed? Dig you peg the jewel hole and maybe accidentally push the stone too far in? you can try using penetrating oil and gently pushing the cap jewel out a bit, just make sure you re-clean them afterwards. also do you have a pic of the entire movement?

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how was it behaving before you dis-assembled it? if it was the same then it could be any number of things, wrong jewels replaced, wrong escape wheel, jewels inserted wrong, bent bridge etc. if it started after you touched it then it may be something you did, but just to understand it runs fine without cap jewels installed? Dig you peg the jewel hole and maybe accidentally push the stone too far in? you can try using penetrating oil and gently pushing the cap jewel out a bit, just make sure you re-clean them afterwards. also do you have a pic of the entire movement?

Hello JDM and saswatch88. Thanks both for your quick replies. I should have mentioned the watch came to me as a non-running project, and also that the movement is an AS1187/94. With the top and bottom end stones installed the escape wheel will just about respond to a puffer at full burst. It isnt possible to transmit power through the gear train if power is applied to the great wheel with brass tweezers. However, slacken off either the top or bottom end stone (thus creating clearance) and the gear train passes my test criteria - that is the escape wheel responds smoothly to the slightest steady puff of air and transmits rotation back to the great gear. Also power applied externally at the great gear is now smoothly transmitted to the escape wheel.

What I cannot recall during stripdown is discovering any non standard spacers which might have jacked up the end stones or the bridge, thus artificially creating clearance.

I agree with your sentiments JDM ... shortening the pivot isn’t desirable as it’s irreversible.

Usually I work on watches which present a problem related to excess end shake! This is a first.

Oh one last thing, yes saswatch - I have tried pushing the end stones into their plate. But thank you for pointing this out.

Regards
Deggsie


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Depending on pivot shoulder it may run fine without one or both end stones.

If you must keep both end stones on and make adjustment, you can push out both end stones, one may not move out adequate to free the pivot ,without falling off itself. Reinsert if it did fall out. 

Fitting another end stone with deeper concavity can be an option, or end stone+ spring. But shortening a pivot :startle:

Sas  outlined several common approaches to increase distance between end stones .

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Hi Nucejoe. Good to hear from you.

I agree adjusting the pivot length is like amputating an arm because it’s itching. But... all things considered, I believe it may be out of specification, (perhaps replaced and not properly adjusted?)

 

Try to bear with me and visualise this if you can. The overall length of the escape wheel axle (pivot to pivot) is x.xxx mm. Now, as you know, the end stones are ‘rubbed’ into a stepped pocket in their keeper-plates and the keeper-plates are then screwed snugly into pockets - one machined in the main-plate, the other machined in the bridge. So far so good?

 

Ok, with bridge screwed nicely onto the main-plate, the distance from bottom of pocket in the bridge to the bottom of the pocket in the main-plate is measured less than x.xxx mm. I.e the escape wheel staff axle is definitely too long.

 

So, your suggestion that changing position and/or geometry of the end stones could correct the problem seemed a logical one. But.... I pressed the buggers as hard into their keeper plates as I dare (I fear the thin stones may crack if if push any harder). They were bottomed out and didn’t move any deeper, so no gain in end shake.

 

Changing the geometry of the end stones to concave..... phew, it may be easier hone the pivot length after all

 

Reluctantly I may just trim a gold foil dial-washer and place it under the keeper-plates to pack them up. It’s a bodge, but not sure what more to do?

 

Kind regards

Deggsie

 

 

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2 hours ago, Deggsie said:

Hi Nucejoe. Good to hear from you.

I agree adjusting the pivot length is like amputating an arm because it’s itching. But... all things considered, I believe it may be out of specification, (perhaps replaced and not properly adjusted?)

 

Try to bear with me and visualise this if you can. The overall length of the escape wheel axle (pivot to pivot) is x.xxx mm. Now, as you know, the end stones are ‘rubbed’ into a stepped pocket in their keeper-plates and the keeper-plates are then screwed snugly into pockets - one machined in the main-plate, the other machined in the bridge. So far so good?

 

Ok, with bridge screwed nicely onto the main-plate, the distance from bottom of pocket in the bridge to the bottom of the pocket in the main-plate is measured less than x.xxx mm. I.e the escape wheel staff axle is definitely too long.

 

So, your suggestion that changing position and/or geometry of the end stones could correct the problem seemed a logical one. But.... I pressed the buggers as hard into their keeper plates as I dare (I fear the thin stones may crack if if push any harder). They were bottomed out and didn’t move any deeper, so no gain in end shake.

 

Changing the geometry of the end stones to concave..... phew, it may be easier hone the pivot length after all emoji3.png

 

Reluctantly I may just trim a gold foil dial-washer and place it under the keeper-plates to pack them up. It’s a bodge, but not sure what more to do?

 

Kind regards

Deggsie

 

 

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Hi Deggsie, One problem with shimming is the darn thing goes un-noticed and gets washed away, leaving the next serviceman baffled as to how on earth did he end up with longer arbour so Gauging the keeper-plate is not frowned upon as much as main plates and is sort of permanent.  Another approach is to make little bump on the keeper- plate.  I don,t think Nickelsilver with all the tools abailable to him, would opt any of the above, specially on a museum piece. How about awaiting his advice.

 

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I realise I’m not the clearest of people when describing in text... so here is a sketch I did over breakfast which hopefully clarifies the setup. I think it’s typical for 1000’s of movement types. With both end stone keepers screwed in, the stones compress onto the tips of the escape wheel pivot causing it to bind
debd6eb085c3e093ae9ebf3a97308492.jpg


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That's an odd situation, especially as there's a full bridge across the train, not just a little cock. A cock can get tilted either intentionally or by accident, a bridge that size not really. There's no simple way to increase the endshake there, aside from shortening one of the pivots.

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4 minutes ago, nickelsilver said:

That's an odd situation, especially as there's a full bridge across the train, not just a little cock. A cock can get tilted either intentionally or by accident, a bridge that size not really. There's no simple way to increase the endshake there, aside from shortening one of the pivots.

But the OP is telling us that the binding is on the cap jewels, and it goes away when just loosing them? So it's the pivot tips that exceed, not the shoulder. Why moving the stone or raising the setting would not work well?

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Just now, jdm said:

But the OP is telling us that the binding is on the cap jewels, and it goes away when just loosing them? So it's the pivot tips that exceed, not the shoulder. Why moving the stone or raising the setting would not work well?

With a cap jewel it is just the pivot tip that limits the shake, yes. No way to move the cap jewel in its setting; you do see prick marks where the cap would seat sometimes to raise it up a bit but this is not really the right way. It's possible that AS had different versions of this caliber with no cap jewels or one cap jewel; maybe they used the same escape wheel for all maybe there were different versions, I don't know. The least invasive would be a shim as mentioned above, at least no damage is done.

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6 minutes ago, nickelsilver said:

With a cap jewel it is just the pivot tip that limits the shake, yes. No way to move the cap jewel in its setting; you do see prick marks where the cap would seat sometimes to raise it up a bit but this is not really the right way. It's possible that AS had different versions of this caliber with no cap jewels or one cap jewel; maybe they used the same escape wheel for all maybe there were different versions, I don't know. The least invasive would be a shim as mentioned above, at least no damage is done.

Thanks for the clarification and I'm glad to learn that what I had suggested doesn't belong to the realm of nonsense.
Indeed I had worked on a Lorsa where only one escape wheel cap was present, I was surprised then but now I understand how certain details "may depend", even more as in my case it was a mov't used for a standing small clock. 

Edited by jdm

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3 hours ago, Deggsie said:

I realise I’m not the clearest of people when describing in text... so here is a sketch I did over breakfast which hopefully clarifies the setup. I think it’s typical for 1000’s of movement types. With both end stone keepers screwed in, the stones compress onto the tips of the escape wheel pivot causing it to bind
debd6eb085c3e093ae9ebf3a97308492.jpg


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  very good sketch.  "gear train bridge"    would that be the balance cock?  as explained, a "test shim"  under the cock is the easiest way to test the shake.  unfortunely;   some would leave it that way rather than shorten the ballance staff.   not good.  vin

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Hello Vin and thanks for your kind words re my sketch

The escape wheel is definitely sandwiched between the gear bridge and the main plate. Definitely not the balance cock and main plate on the one.

I’ve now managed to eliminate the friction temporarily by slackening off the tiny screws which hold the end-stone keeper plates in position. This has eliminated the resistance, but... still no end-shake which I do want to see with the screws nipped up, so some work required in the future to get that.

Good news is it’s now assembled and running, but the bad news is it’s very poor. Even with a nos mainspring installed, the timegrapher results are poor for different orientations. Just as a rough idea, here are the recordings from my note book a moment ago
b274d55cf15f754ac7399b6cb21267be.jpg

I’m going to clean this movement again using WP Pro which I purchased from cousins, reassemble it dry, and retest to see if the amplitude improves. If it has... then I will lubricate it.

Kind regards
Deggsie


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Sorry, I will report back on this maybe next week. I didn’t get chance to re-clean the movement today. Out of courtesy for the good help you’ve offered, I will keep you informed of the results. What I would add is the hair spring appears perfect - no kinks, concentric is good and it lays flat. Usually my low amplitude issues lead back to poor hairsprings, (or old mainspring) but I don’t think it can get better in this case. I also degaussed the movement but it made no difference.

 

Thinking aloud here, if the balance has lost poise, would amplitude be effected in the horizontal planes ie dial up or dial down? Am I over thinking this?

 

All the best

Deggsie

 

 

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8 hours ago, nickelsilver said:

With a cap jewel it is just the pivot tip that limits the shake, yes. No way to move the cap jewel in its setting; you do see prick marks where the cap would seat sometimes to raise it up a bit but this is not really the right way. It's possible that AS had different versions of this caliber with no cap jewels or one cap jewel; maybe they used the same escape wheel for all maybe there were different versions, I don't know. The least invasive would be a shim as mentioned above, at least no damage is done.

that is true... this caliber had a version with 2 cap jewels for the escape, which is why i think someone must have had their hands in it before replacing the wrong escape wheel. Which would explain why this would be happening before the OP touched it. You can find these AS movements all over the bay. Same parts are interchangeable from one caliber to the next. i would try sourcing a parts movement before messing with jewels and pivots. The ranfft link below will list similar calibers. After doing an ebay search there plenty of 1187 watches, movements, and parts available since it happened to be a very popular movement during the time.

http://www.ranfft.de/cgi-bin/bidfun-db.cgi?10&ranfft&0&2uswk&AS_1187

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Hello saswatch and thank you. Reading your reply gave me a eureka moment. It seems the nos mainspring I purchased was not correctly identified by the eBay seller and is too short as well as too narrow and too thin!

 

The photos below show the mainspring dims as per Ranft and the dims of the mainspring I purchased. Presumably such undersizing would mean the impulse kick to the balance wheel would not be strong enough to achieve correct amplitude?

 

50568ec55dbe63a9dc025f4f835b7a38.jpg&key=d33da043354d69fbd5d6f9a6de046741dc2194605c6654ec362d4d114d164a16565d0f81c1bde6535a64ca62ccf19c34.jpg&key=3af590ba1c1824554d8a8c0e8393e8de525e163d6e894cdf605226254127b9a6

 

Kind regards

Deggsie

 

 

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There is a problem with NOS main springs where the original packaging states the dimensions but fails to identify which particular system is being used to describe them. The problem only gets worse when someone has hand written what they think those stated dimensions are in metric, unless they have actually taken the spring out of the packaging and measured it (which is a whole other can of worms!!).

The problem is that there have been several completely different standards used in the past for describing main springs, some of which were even specific to just one m/s manufacturer, and unless the packet states which system was used to describe its contents it's impossible to know if whoever did the conversion to metric used the right conversion values

According to my collection of old m/s gauges a "Lever" value of 5 is about 1.7mm, a "Geneva" value of 5 = about 1.6mm to 1.55mm, and a "Dennison" value of 5 = 1.4mm.

For strength values my Dennison/metric slot gauge only goes up to a Dennison value of 12, which equals 0.06mm, and my DTR/metric gauge has a DTR value of 19 = 0.07mm.

I think your best bet is to measure your m/s to check that the converted values are accurate. If they are then the lower strength is likely to result in a drop in amplitude, and the shorter length will reduce the power reserve.

As far as the strength is concerned I say "likely" because you also have to factor in the fact that modern white alloy springs tend to be more powerful than their old blued steel equivalents, so if the original spec is derived from a blued steel spring then a reduction in thickness of .02mm may be countered (at least in part) by the more powerful stock material.

If on the other hand the strength value printed on your packet is in DTR, 19DTR = .07mm, and it's a blued steel spring, and the values quoted on Ranfft are for a modern alloy spring (which is almost certainly the case), then your spring is seriously under powered and will result in low amplitude.

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Hello Marc. Thanks so much for your well informed response. Fortunately the mainspring was only £3 on eBay and I’m sure the seller played no part in marking or identifying the spring. He or she probably just went by what was on the packet and made a mistake.

So, if I correctly interpret what you’ve written, the ms length dictates the reserve time, and ms cross sectional area + ms material properties will dictate the strength (and hence the kick to the impulse jewel?)




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3 minutes ago, Deggsie said:

So, if I correctly interpret what you’ve written, the ms length dictates the reserve time, and ms cross sectional area + ms material properties will dictate the strength (and hence the kick to the impulse jewel?)

Broadly speaking yes.

Power reserve comes down to how many turns of the arbor you can get before the spring becomes tight wound. This is a function of how much free space there is between the arbor and the unwound spring, which comes down to the diameter of the barrel and how many coils the spring makes against the barrel wall, as determined by how long it is.

As you say the strength is primarily down to the cross section area, but since the height is determined by the height of the barrel, thickness becomes a direct descriptor of strength.

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Hi again Marc.

I recollect the newly installed spring seemed to occupy a small volume in the barrel. Just looked at Donald Decarlo and reminded myself that he says spring should appear 1/3rd arbour, 1/3rd air-gap and 1/3rd spring wound out tight to barrel wall. If I’d remembered this, alarm bells should have gone off!

I’ll post a photo later showing the spring in the barrel, but convinced now that the lack lustre amplitude is mainspring related. Everything else seems to run very freely both in isolation and as a system.

Can I just say many thanks to everyone who has kindly taken the time to help me with the two issues I’ve had relating to this watch, and, also in a previous post relating to the same watch where I asked if anyone recognised it - it’s a Bel-Air by the way.

Kind regards
Deggsie


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Ignoring the different Swiss and metric spring dimensions, and looking just at the simple barrel size recommendation, I think you’ve got a 6.5mm spring in a 9mm barrel. 

It’s a simple way to filter through mainspring sizes without having to consider the amount of space taken up by the combination of length and thickness. 

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Yes. You’re right. I just took out the barrel, removed the lid and measured the internal diameter of the AS1187 barrel. It’s 9.25mm. The anodised washer in which the new spring was safely stored has 6.50 stamped into it. Here are the photos I promised:

a5da2b6613c8fecaa55913a61ad743a7.jpg&key=be0d3baaafbe53f6a7fb9798c1a922a644cbeae13488bb233cbd46b675bd04a0e9a2d48c8fbacaae7d8f88be95610fcb.jpg&key=34d5b51af888da08a5b66bf811ea296803a9d72633f5a841187c392453b31598af9b1ed282288b22e89267e55611186b.jpg&key=0df827cb05f4ee12df017df7dceb94e57f1cdd24750028c8b727911abfa3e98f

 

I image it’s feeble compared to the correct spring.

 

By the way, the watch guy has an excellent database for GR (General Ressorts) mainsprings on his web site. It will now hopefully allow me to search eBay for movt numbers other than AS1187/94 to find the same mainspring.

 

https://watchguy.co.uk/cgi-bin/mainsprings

 

Kind regards

Deggsie

 

 

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1 hour ago, Deggsie said:

Yes. You’re right. I just took out the barrel, removed the lid and measured the internal diameter of the AS1187 barrel. It’s 9.25mm. The anodised washer in which the new spring was safely stored has 6.50 stamped into it. Here are the photos I promised:

a5da2b6613c8fecaa55913a61ad743a7.jpg&key=be0d3baaafbe53f6a7fb9798c1a922a644cbeae13488bb233cbd46b675bd04a0e9a2d48c8fbacaae7d8f88be95610fcb.jpg&key=34d5b51af888da08a5b66bf811ea296803a9d72633f5a841187c392453b31598af9b1ed282288b22e89267e55611186b.jpg&key=0df827cb05f4ee12df017df7dceb94e57f1cdd24750028c8b727911abfa3e98f

 

I image it’s feeble compared to the correct spring.

 

By the way, the watch guy has an excellent database for GR (General Ressorts) mainsprings on his web site. It will now hopefully allow me to search eBay for movt numbers other than AS1187/94 to find the same mainspring.

 

https://watchguy.co.uk/cgi-bin/mainsprings

 

Kind regards

Deggsie

 

 

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Yes, Ranfft is awesome but not infallible for some info; just checked my Generale Ressorts book and they say ref. 4502, 1.60x 0.105x 280 8.5.

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