Geneva Stop Works Binding

[Woolshire]

I noticed the lack of clearance between the cover and the two wheels of the stop works but figured it must be okay since that’s the way it was built. I set it up and put the cover over and put the two screws in the cover. Wound it up and it ran good for a while and then stopped. I knew it had to be a power issue. I started to unscrew the stop-works cover and the watch started right up. It works fine as long as I don’t torque the screws down.
Have you seen this? What type of lubrication do you use on the stop works, if any?

[JohnR725]

6 hours ago, Woolshire said:

noticed the lack of clearance between the cover and the two wheels of the stop works but figured it must be okay since that’s the way it was built

Look really carefully at the cover and the components because was it really made that way originally? Just because it's that way now doesn't mean it was made that way perhaps?

To give you an example I swiped the picture off online typically and I don't remember the terminology the various wheels but one of them like in the image is held on with the screw. So if you take your cover off does it look like that component at a recess for a screw? Then the other  part with the finger typically there be a little slot and a hole and a really tiny pin held it on. So if you take your cover off if you see signs of that and that's the way it used to be somebody modified it. But there is a possibility that that's the way it was made in which case it should work even though it doesn't appear to be?

[jdm]

9 minutes ago, JohnR725 said:

So if you take your cover off does it look like that component at a recess for a screw?

I think the screw for the Maltese should have a shoulder or small washer to prevent binding on the bridge. The other screw is less likely to be the one causing binding. The two wheels should be tested and adjusted separately first.

[nickelsilver]

This setup was typically used by Patek- I wouldn't be surprised if this watch has a "moustache" counterpoised pallet fork. Otherwise they're usually as John described.

 

Have a look at the finger. They usually have a small boss on one side, that fits the center hole of the bridge. If that's facing down it will bind. Also it's probable the bridge isn't symmetrical despite looking like it, it may work better one way than the other. Otherwise, just check for burrs or debris that may be causing the binding. If all checks out, figure out if it's the finger or cross or both that are binding, and when you're 200% sure it's not something else, you can reduce the thickness of the guilty component until it's free.

[Woolshire]

Yes, Patek. Great watch and the fit of everything is flawless. That’s why I was surprised this stopped it. I took it apart and didn’t find anything notable. Do you lubricate any of this? I’ll figure it out but still baffled.

Almost 100 yr old watch and 300 deg horizontal amplitude (260-270) all side orientations with flat hairspring (no overcoil)….and, yes mustache black polished both sides pallet fork. Interesting that is such a work of art but the escape wheel isn’t polished, except for the tips. They’re all that way. I’ve seen several examples.

[jdm]

56 minutes ago, Woolshire said:

mustache black polished both sides pallet fork.

What was the idea with the additional weights? It adds inertia, the pallets will need more energy to get moving and more friction to the escapement to be stopped. Recently somone asked about an Elgin fork thas us the same. 

[nickelsilver]

3 hours ago, jdm said:

What was the idea with the additional weights? It adds inertia, the pallets will need more energy to get moving and more friction to the escapement to be stopped. Recently somone asked about an Elgin fork thas us the same. 

The idea was it would help the rate in the vertical positions, but as you note the increase in inertia did away with any benefit.

[nickelsilver]

4 hours ago, Woolshire said:

 Do you lubricate any of this? I’ll figure it out but still baffled.

Almost 100 yr old watch and 300 deg horizontal amplitude (260-270) all side orientations with flat hairspring (no overcoil)

 

Lubricate the cross, could also lightly grease the finger where it contacts the little bridge, but all dry should still work fine.

 

Keep in mind this likely has a lift angle as low as 38 degrees if getting amplitude from a machine and not visually!

Edited February 11, 2022 by nickelsilver

[Woolshire]

Lift angle is 45 deg, I do believe.

back to the binding issue; I have placed small timing washers under each screw to allow full tightening, as a temporary fix. I’m determined to figure out what I’m doing wrong without that fix. It didn’t bind with the old mainspring, which was quite past its prime. However, new spring and it binds. Could it be a correlation, such as a torque from the arbor square through the barrel hole? I mean too much sideshake in barrel?

[Woolshire]

So I believe the issue was that the screw going through the cover at the Maltese was just a hair too long and actually touching the mainspring. I had replaced the mainspring during service with the same dimensions (Dennison 3/ 1.20mm). It could be that screw wasn’t torqued that extra quarter turn before?

anyway, three swipes of the bottom of that screw across a stone and problem gone…Interesting how many little things can turn out to be the issues we encounter. Thanks for everyone’s replies and help.

[nickelsilver]

So glad it worked out, and was a small issue- as is usual in some of these old handfitted movements haha.

 

To the rough looking escape wheel: On a lot of high end Swiss stuff from ~100 years back**, the escape wheel would be x thick (maybe 0.2mm on a pocket watch) and reduced in thickness everywhere but the functional tips, so the middle might be 0.15 or even less, this reduced the inertia of the wheel- which harkens back to the inertia of the fork that JDM mentioned. The reduced area typically had a grey finish, from some kind of grinding paste, and the tips themselves would be flat polished on the sides, with a beveled edge on the inclined plane that gives lift to the fork, front of the escape tooth polished, face working on the fork polished as well. A huge job to manufacture, but worth it. I worked on some prototypes of a "planetary" 3 axis tourbillon 8 or 9 years back, we made everything except the balance and escapement, which were supplied by a highly respected maker. The escape wheel was either made by liga (3d metal printing) or laser cut. Teeth were full thickness, zero finishing... even really cheap watches from 60 years back had the escape teeth beveled on one edge to reduce contact area with the fork and a decent finish. We made 6 protos for the client (after the first functional- 6 working protos)- on all of them we beveled the escape teeth by hand one by one, tooth by tooth, polishing the functional surfaces, as the resultant increase in amplitude and rate improvement was well worth it!