Antique Pocket Watch Identification and Restoration

Ive installed the replacement mainspring and it’s running on its own. Problem is the amplitude is quite low. I double checked my measurements on the old mainspring and am getting thickness values from 0.15mm (what I replaced it with) to 0.18mm. I wasn’t getting this level of inconsistency before.

It makes sense that if I’ve undersized the mainspring it would have this result. A 0.18 thick mainspring will be 1.75 times stronger than a 0.15mm all else being equal. New ones are on the way (0.17mm & 0.18mm). It runs the same regardless of the position I hold the movement in which is also fantastic news.

 

When I came down to the lab yesterday morning (teleworking is great) I noticed that the watch had stopped. After work, I took a look at a few things under magnification and found a bit of scoring on the mainwheel's pivots. I used a bit of ebony to smooth out the scoring in the bushings themselves. It's not gone, but I no longer see any evidence of raised ridges. I used a 7000 grit piece of sand paper (wet) and then some jewelers rouge to do the same to the pivots on the staff. I know this isn't ideal but it is the most that I am comfortable doing. Remember all you boys and girls out in f-chat land, I'm an amateur, not a professional. In a perfect world, I'd want to take a smooth broach to each bushing and burnish the pivots to a mirror finish. I'm afraid that is beyond my level of "guts" right now though. I do not want to risk opening the bushings up too far or damaging them or the pivots on parts that are irreplaceable. If it weren't such a sentimental piece, like one of the eBay movements I buy to fix, I wouldn't hesitate to give it a go. Those have little monetary value and no sentimental value though plus I can usually find replacement parts for just a few dollars. None of that is the case for this piece. It appears that the amplitude has increased roughly 10-15 degrees as a result.

After completing that work and thoroughly cleaning everything again, I reassembled and wound the movement. This morning, as of 10.00 EST, it is still ticking away without issue. I still feel extremely confident that the properly sized mainspring (thickness) will solve the remaining issue of amplitude. Then I can finalize the assembly and adjustments.

 

I’m happy to say that it has run for right about 22 hours now and is still going. I’ve been setting it in different orientations throughout the day and aside from the low amplitude, it looks to be in good shape.

Back to waiting on parts (replacement mainsprings).

 

This continues to be one of the cooler threads on FChat.

 

Since I've been talking about run time, here's a little more info. The mainspring barrel in this movement has 80 teeth. The center wheel pinion has 10 leaves (name for teeth on a pinion). The largest mainspring I've ordered based on the measurements I retook of the one that was in it is 0.18mm thick and 460mm long. Based on the mainspring dimensions along with the inner diameter of the barrel and outer diameter of the arbor inside the barrel, the mainspring has, in theory, 8 usable turns from fully wound to fully unwound.

That all boils down to the following; In theory, this watch has 64 hours of running time. Typically that would mean 48 hours of operation with a 16 additional reserve. The owner would typically wind it each morning or at least approximately at the same time each day but with this it could go two days between windings and have plenty of room for error. I'm not sure if I'll be able to get the watch back to that full running time as near the end of the spring being unwound the force drops off precipitously and with the age and wear of the pivots and bushings, there is bound to be more friction than when brand new. I certainly think we'll do better than the 24+ (I don't know when it stopped over night so it could be closer to 30) of running on the spring which I think I've mistakenly undersized.

Anyone want to venture a guess?

 

I’m still a bit aggravated over the mainspring measurements. So last night I had an idea for a sanity check. What size mainsprings to similar movements from known brands (Elgin, Hamilton, Longines, etc.) use? Well, from what I found it appears that most of those which are 7J Swiss-lever (couldn’t find much for cylinder escarpements) use springs from 0.18-0.22mm in thickness and generally somewhere around the 2.00mm width. Thinner springs were only common to the 15-17 jewel movements. The increase in Jewel bearings vs the bushings which are used in this movement really lowers the friction losses through the gear chain. So, I feel a bit better about looking at thicker springs now.

That doesn’t make me feel any better about the mistake. I going to see if it is possible to calibrate my calipers and micrometer with a good quality gauge block.

 

Pol,

I think you are approaching the search slightly incorrectly. While the characteristic "jester" in the movement is a key identifier, it is not uncommon. The first identifier is that it is a cylinder escapement. The second is the bridges and plates (what you are looking at). The third is that it is partially jeweled. All of the movements you have posted are lever escapements. While there are several very high end makers that made cylinder escapements, this watch was not made by one of them. This is an honest, mid-range, European made (probably Swiss, possibly French) working man's watch.

It is possible that the ébauche's manufacturer uses the "jester" as a signature but I'm not certain of that.

Please note, I'm not trying to dissuade you from searching, only to help your efforts.


Rich,

Really nice job so far, cylinders don't have as strong of a swing as regular escapements so that balance looks really good and its swing is almost strong enough. I'd say you are aiming for 200 degrees total - don't try to make it hit the pin. If you aren't there already, I think if you polish the other pinions, you'll be there.

The oil was originally a fine whale oil. Assuming you aren't trying to be that authentic in the restoration, I would use something at the heavy end of American watches to compensate for any wear. Maybe the oil specified for a model 1857 Waltham.

Regarding the mainspring: start with the obvious; clean the one it came with, maybe add a touch of your lightest oil, pop it back in and see what it does. You may be pleasantly surprised. Also, would you mind posting pictures of the interior of the mainspring barrel and its associated parts?

Finally, as a reminder, these watches weren't that accurate when new. This one is no longer new. If it runs well in all positions and keeps time within a minute or two over an afternoon, you should consider yourself wildly successful!

Regards to both,

Art S.

 

Today I did something I have been VERY nervous about trying to do. I’ve never attempted it before and nothing of @PhilB ‘s was ever in any danger which really helped calm my anxiety. I knew I’d get there eventually, but I didn’t dare dream I’d have nailed it (my opinion) on my first try. Ladies and Gentlemen of F-Chat, may I present to you my first, hand-made, watch screw!

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The one in the left is the original part, dial foot retaining screw, that came in the movement. The one on the right is the one i made to replace the missing one (ok, only part of it was actually missing, the rest was broken off in the mainplate)!

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...and proof that it fits! One of the few steps I’m aware of that was left to bring back this timeless memory. I cannot express the joy or pride or whatever this feeling is knowing that a little part of my handiwork will forever (hopefully) be a part of this movement now.

 

Tick-tick-tick-tick-tick-tick-tick-tick-tick...

Sweet, sweet, music to my ears! The new mainspring is in, the replacement crystal is bonded in place, and that beautiful sound echos through the silence of my lab. I do hope to be able to return this little treasure to Phil soon and then I’ll post a few photos to close out my contributions here.

We’ve not found out who made it or when yet, but I (and I suspect a few others here as well) will continue to chase those answers when hunches sneak into our thoughts.

 

Subscribing for the exciting conclusion....

 

How did you make that screw? Just an amazing story.

 

Not the way I had planned on it, that’s for sure.

I wanted to set it up on my mill and do it that but I don’t have a sharp enough pointed lathe tool/grave. I didn’t want that to keep me from completing this by Christmas though. It would be nice if I had a small lathe but alas, that’s not something I’ve added to the lab yet. Time to be creative.

I chucked a piece of tool steel in my Dremel and clamped the Dremel in my bench vise. Running it at low speed I used some jeweler’s files to shape the material blank. After it was sized, I ran the end through a threaded die.

I then put a threaded hole in a block of material on my mill and machines the slot in the top with a 0.30mm diameter end mill.

A touch with a butane torch and a little polishing but not enough as to make it stand out too much and the screw was done.

 

I cannot imagine how you do this kind of stuff on such a miniature scale. They make thread dies that small???!!!???

 

Indeed they do. I have one similar to the cheap item in the picture below. The “7” indicates that the smallest thread is a 0.70mm major diameter. I found the threads not to be made really well so I used one of my taps to chase through the 1mm die and then it worked really well.

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I’m hope that Phil will have at least one more post to add here, but for me? I’m happy to say that the “mystery movement” has made its way back to the hands of its owner as of this evening. I don’t know if I can explain how honored I am to be entrusted with projects like this. The challenges posed have made me learn some new skills and about the cylinder escapement mechanism.

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If you’ve found reading about this project to be interesting and are a silver subscribed member here at f-chat, please check out my thread in the silver subscribed sub-forums called “Horology and Me”, keep an eye out for others threads to pop up here after the New Year, or follow me on Instagram @aleatoryhorology.

 

Love this thread!

 

Definitely the best Fchat story with a happy ending for 2020. Simply brilliant craftsmanship and knowledge sharing.

 

+1 to Rich. Impressive indeed!

 

Just when I thought this story may have reached its end... I find this today in a small box (that I did not order) on my door step...

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The “Mystery Movement” has a twin!!!

 

Better late than never :^)

Merry Christmas!

 

I don’t know how you managed to find it but maybe this one will have some additional markings to aid in the search!

 

Rich,

I found it by following the advice I gave Pol and a bit of luck.

I wouldn't hold your breath on figuring out the maker, but maybe. I suspect we will eventually figure out who made the ébauches. If we figure out who finished them - that will be truly impressive!

Regards,

Art S.

 

Please post how you found the "twin". Plot twist to an already interesting story. Cheers.