Full plate watch, Suitable tool for adjusting & testing pallet stones?

[mbwatch]

I find myself in a frustrating situation, and if I have learned anything yet it's that there might be a specific old tool to get me out of it.

I am rebuilding an early grade Elgin 18 size full plate movement, just restaffed and installed a new roller jewel. Next I found that the pallet stones were loose and added shellac to them, reassembled but the watch does not run. Observing the escapement through the holes, it is clear the entry stone needs to move in slightly. So I know what I need to do at this stage, but I fully expect to need a few adjustments of one or both stones. I don't want to move the banking pins because it did want to tick before I noticed the pallets were not secure.

Question is, on a full plate movement this is incredibly inconvenient to make a change, let the shellac harden, and reassemble the entire full plate watch in order to observe the escapement action.  It can only be seen from the dial side through the small holes in the pillar plate, so even the balance must be installed in order to manually operate it from the back. Anyone know how this was done 120 years ago? Is there a tool or fixture that can be used for the job outside the watch? Depthing tool maybe?

You all like pictures, so here are some. Final cleaning has not happened yet, thus the dirt and oil on the 4th wheel jewel.

[Randy55]

Afraid this is where it could get down to old school adjustment and observation.

There are pallet setting tools..but the calibrated ones aren't cheap.

The observation holes in the plate will allow you to see if you have one or both stones hanging up/ not engaging on a tooth, That would ofcourse require you to disassemble, heat/move the jewel in/out as required..by eyesight and experience. It's truly trial and error until you get close enough that you could make small adjustments with the banking pins until they drop to the lock freely.

You can use a Potence tool to help hold the rok in place during reassmbly.

Here's a pic of one...made with a piece of old 18s mainspring

You just fold over a roughly 2 inch piece, then file a slot on the end that engages the pallet fork arbor

Edited 17 hours ago by Randy55

[mbwatch]

1 hour ago, Randy55 said:

Here's a pic of one...made with a piece of old 18s mainspring

Oh that's neat. I typically use a thin strap of rodico laid over the pallet fork to affix it to the upper plate but it can be hard to retrieve sometimes.

And as I did more research, I may have just found your own earlier explanation: https://learntimeonline.com/forums/topic/potence-clip-for-full-plate-p-ws/

[Mercurial]

There is a tool that was made for setting up and adjusting escapements of full plate watches. 

There were two styles, the picture below shows both of them. 

The lower tool held a movement plate and the vertical pointed rods were adjusted to hold the unsupported pivots of the lever and escape wheel. 

There was also a version of this tool that had 3 adjustable safety centres so that the balance pivot could be supported by the tool : 

The other version I’m aware of is the Boynton’s Escapement Matching and Examining Tool came as a set of two or three clamps that gripped the watch plate and held the safety centres for the pivots :

These do turn up on eBay from time to time. 

For some escapement work, you can set up the parts in a regular depthing tool, with the centres set according to the distance between the corresponding pivot holes on the movement. 

I hope this helps,

Mark

[nevenbekriev]

Yes, the specific old tools do exist, but may be having one is not needed as they are not cheap, and also You will be able to do without it well enough.

My advice will be to use regular depthing tool and adjust it for the exact distance between pallet fork and escape wheel bearings from the watch. Then remove the shellac from the pallet that now doesn't pass the ew teeth and move this pallet in. Then put the pallet fork and ew on the depthing tool and check how they lock. They should not lock when the pallet is in, but You will little by little move the pallet out and locking will appear. Then move just an idea out for reliable work and apply shellac, then check if things are still the same. You have to observe where the teeth fall on the pallets - it must be just a little below the edge between impulse and rest planes. Then You must check how everything behaves in the movement

13 hours ago, Randy55 said:

Afraid this is where it could get down to old school adjustment and observation.

There are pallet setting tools..but the calibrated ones aren't cheap.

The observation holes in the plate will allow you to see if you have one or both stones hanging up/ not engaging on a tooth, That would ofcourse require you to disassemble, heat/move the jewel in/out as required..by eyesight and experience. It's truly trial and error until you get close enough that you could make small adjustments with the banking pins until they drop to the lock freely.

You can use a Potence tool to help hold the rok in place during reassmbly.

Here's a pic of one...made with a piece of old 18s mainspring

You just fold over a roughly 2 inch piece, then file a slot on the end that engages the pallet fork arbor

This Potence tool is so ingenious, but actually, the traditional way to do the things is much more simple. Arrange the parts not on the pillar plate, but on the cover plate. Only the central wheel will remain on the pillar plate, secured by the cannon pinion.

Edited 4 hours ago by nevenbekriev

[JohnR725]

19 hours ago, mbwatch said:

I don't want to move the banking pins

Interesting philosophy I like that but what if, I know this is extremely unlikely after all it's not like they're easy to move what if somebody moved them before you worked on the watch?