# From the Watchmakers Bench - Patek restoration



## Guest (Dec 7, 2016)

This really nice Patek pocket watch arrived on the bench with many serious problems.

If you look closely you should be able to identify the first problem, can you see it (or more accurately what's missing?)



*Broken escape wheel arbor*

If you didn't notice it, here's what also arrived with the movement, the escape wheel with the arbor snapped off. It snapped as a result of botched workmanship.



The arbor is unusable and in order to fix it, I will have to make a new arbor and attach the new arbor to the escape wheel. The only way to attach the new arbor to the escape wheel is to drill a hole in the escape wheel and press fit a new arbor in place. I don't have a new arbor, so I'll have to make one.

First step, mount the escape wheel by it's pinion in my lathe so that I can do some drilling.



In order to carry out the drilling, the wheel is held in the lathe and turns while the drill is held fixed in the tailstock. The hole I am going to drill is 0.25mm in diameter. Here is the drilling taking place, you have to be so careful with the amount of pressure you apply to the drill, too much and the drill will snap, and then you have to somehow remove a broken drill from a 1/4 of a mm hole, not something I like to do. This is a really critical job and very easy to make a mistake, best to put up the DND (Do Not Disturb) sign on the door.



As per standard practices I drill the hole to a depth of *3X the drill diameter* so 0.75mm deep, here are the results.

Don't let the large apparent size fool you, the hole you see measures *0.25 mm in diameter*.



*New arbor*

With that out of the way, and my heartbeat back to normal, I mount a piece of silver steel hardened and tempered blue, in the lathe and cut the new arbor by hand with a graver. The pivot at the right tip measures 0.11mm and the arbour diameter is around 0.35mm thick, eventually tapering down to 0.25 for insertion into the escape wheel hole I drilled.



Here is a view of the new arbour on top (not finished still need to reduce the diameter of the big end to 0.25mm for fittment into the escape wheel) old broken arbor below, note the much longer pivot on the new arbor which is made longer for sizing after installation.



I carefully press fit the new arbor into the drilled hole in the lathe, making sure to line it up and verify that the wheel runs true, running true is a challenge for such a long arbour.



Next installed the escape wheel into the movement and I check side and end shakes, note the extra pivot length sticking through the jewel, this extra length be reduced to get the proper amount of end shake.



A view with the pivot shortened to just below the hole jewel, with the proper end shake.



Ok, the hardest job out of the way, next up making a new balance staff.

*Balance staff*

The bottom pivot was bent and although I tried to straighten it on my Seitz pivot straightner it snapped off, it must have been really hard. So with no spares balance staff's available, I have to make a new staff by hand from scratch.

I used the original staff as a guide for making the new one, here is a view of the original staff being pressed out of the balance arm after cutting away the rivet that secures the staff to the balance arm.



I harden and temper blue a piece of high carbon steel rod and with a hand graver cut out a new balance staff, here is a view of the staff I made still attached to the lathe. Next it is removed, flipped end for end, and the bottom pivot and roller table seats are cut out.



With the bottom of the staff machined, the staff is installed and riveted to the balance arm, then the roller tables (they are two separate pieces) are pressed in place. Here is an overall view of the new staff and roller tables installed on the balance wheel. Next the poising is checked and adjusted, then the hairspring is installed.



Unfortunately I still have more defects that have to be addressed before this one is completed.

*Bottom movement repairs*

You would have thought that having to make a new escape wheel arbor and a new balance staff would have been the end of the repairs on this watch, but if you thought so you would be wrong.

After the work that was done on the top of the movement, I flipped the movement over and found more defects:

1 - set lever screw stripped, inspection revealed that the hole in the mainplate had no threads left

2 - keyless clutch pinion and lever were mismatched, there is a large gap between the two and the watch can't be wound, and finally,

3 - stem rusted and too small in diameter for the mainplate hole causing all sorts of problem

*Set lever screw*

The original screw was no longer usable since the threads in the brass mainplate were stripped clean. So I made a new screw and tapped the mainplate for the next size up, the original measuring around 1,00mm and my next sized tap being 1,20mm. Here's the new screw I custom made.



Do you notice something odd about where the set lever screw is located and how it accessed, it's not what you normally see. It's under the dial and on the dial side, not on the top of the movement and accessible from the back cover.



*Clutch pinion to lever fittment*

This one I can't explain. The clutch lever fits the mainplate and mates with the rest of the keyless works perfectly and looks like it belongs to the movement, see for yourself.



And the clutch pinion also looks like it fits perfectly and mates with the winding pinion etc, but when you look at the mating between the two: clutch to lever there is obviously a problem, much too much side play. It has to be corrected because the side play is enough to allow the clutch and winding pinion to disengage and when in the time setting position it allows the clutch and intermediate wheel to disengage. Check out the side play.



So after careful thought and dismissing making the lever any thicker by adding material, I decided to make a spacer ring that would fit round the grove in the clutch pinion. Couple of reasons, first rule is that any work should be reverseable and if I welded to the lever to make it thicker I would break rule 1, and secondly any future watchmaker should easily be able to identify what I did and why, so the spacer fits both my requirements.

I made a small ring on the lathe, hollowed it out, cut a slice through one side, bent it open, slipped it in place, squeezed it shut, and what I ended up with works perfectly. See below the clutch pinion and my spacer filling the large gap.



Next I install the lever to see if my idea works, notice now how the lever is actually pressing the clutch into and engaging it with the winding pinion. Although the lever to clutch is not perfect and on a slight angle for some reason, given the alternative this is the only fix. With both surfaces well lubed with KT-22 and regular servicing I don't see any problems due to wear, especially in the winding position as the teeth on the winding pinion and clutch tend to draw the parts together during winding.



*Stem*

As you can see here the original stem leaves a lot to be desired when it comes to fitting the mainplate hole, it's much too small, note the gap between the stem and the mainplate. I would bet that the set lever screw was stripped as a result of this defect, the stem keeps falling out, so to fix that problem tighten the set screw even more...until of course the screw strips and the stem still falls out of the mainplate. Find the cause and correct it, don't work around it, how any watchmaker could fail to notice this very worn out stem is a mystery.



So ignoring the original stem, I made a new stem from high carbon steel that I custom fitted to the dimensions of the mainplate and keyless, here's how it looks overall.



And here is how it fits into the mainplate, gap is gone, no side shake, and the set lever locks into place properly.



And that was the last of the repairs, the movement was fully serviced, oiled and timed and adjusted and performed very well. The variation between positions was less than 1 second/day, very good for a 100+ year old movement. The customer was very happy with the results - to say the least.

Until the watch was sent in, it had been sitting in a sock drawer unused for many years because all attempts to find a "watchmaker" that could fix it failed. I get a real sense of satisfaction from this type of work.

Thank you for reading my post.


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## Karrusel (Aug 13, 2016)

I applaud your skill & photography!

I've been fortunate on occasions to visit the Blancpain workshops at Le Brassus, your attention to detail is reminiscent of such visits & analysis.

I will dig out analysis reports and post if anyone is interested?

Thank you, I do enjoy & appreciate the time it takes to create these posts.

Alan


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## Tazmo61 (Oct 3, 2016)

Superb post , very interesting to read and see , great skill and photography .


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## Caller. (Dec 8, 2013)

Simply brilliant. I'm loving these threads. Did someone take the photo when you were drilling?


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## Pip (Jul 19, 2016)

Agreed, I love these posts and would love to see more like it. It's the amazing amount of work in something so small that draws me to the whole business in the first place I guess. And superb macro photography!


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## Rotundus (May 7, 2012)

:notworthy:


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## Guest (Dec 7, 2016)

Caller. said:


> Simply brilliant. I'm loving these threads. Did someone take the photo when you were drilling?


 Yes someone did take the drilling photo...that would be me  nothing worse while working than having to stop and pick up the camera; however, I have been documenting my work for so long now that it's become second nature, but it does slow down the process. The 'show-n-tell' ability and being able to share it with other watch enthusiasts is worth the effort.


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## Noslho (Nov 13, 2016)

Intricate lathe work, detailed problem solving and excellent photography - is there no end to your skills! Please add my name to the list of those who are loving these threads.

Respect. :notworthy:


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## PC-Magician (Apr 29, 2013)

Superb work and fascinating to read.

More please.


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## Littlelegs (Dec 4, 2011)

Wow, I love threads like these and wish I had the ability to complete such repairs. I wouldn't have any non working watches then. Hat off to you, great work.


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## gimli (Mar 24, 2016)

Thank you so much for these posts. I love pictures of movements and how they're being repaired/reconditioned.


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## davidcxn (Nov 4, 2010)

Another fascinating post exhibiting amazing workmanship and attention to detail. :notworthy:

Your client must have been thrilled.


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## Damo516 (Nov 9, 2015)

Fascinating post and a great read.

Skills.


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## harryblakes7 (Oct 1, 2010)

Excellent work!! Well done!!


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## andyclient (Aug 1, 2009)

Amazing work and a fascinating read thanks for taking the time to photograph and share with us all.


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## Roger the Dodger (Oct 5, 2009)

Great stuff! Keep 'em coming! :thumbsup:


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