Elgin Grade 315: Runs/stops with dial down/up

[LittleWatchShop]

When turning staffs, a JKA is invaluable and expensive. Fortunately, I inherited mine. There are crude alternatives to a lathe...like chucking something up in a Makita drill motor and using various grit sandpaper to make a pin. Won't turn a staff that way!! But, you can make a pin.

[nevenbekriev]

Please do not file nothing. I have no time this days and am able to write here only in midnight time, so please wait...

[JohnR725]

10 hours ago, docrpm said:

This is probably one of those circumstances where I could use a lathe to reduce the diameter of the pin, right

 I don't use a lathe to reduce the diameter of the pin I use something else but I'm a bit puzzled as to why is it too big in this particular case is that's extremely big? By some chances as the balance bridge off another watch?

[docrpm]

@JohnR725 The balance bridge is from the donor. I don’t think it’s bigger…It’s probably the same diameter but the center is displaced relative to the center of the hole in the baseplate. Not by much, obviously. What I was thinking of doing was just “shaving” off the smallest amount possible from the side of the pin where I think it’s creating friction. But @nevenbekriev wanted me to wait, so…  

[JohnR725]

3 hours ago, docrpm said:

But @nevenbekriev wanted me to wait, so…

He's trying to tell you something like this isn't really a good plan.

Just a reminder of something when they quote something from the other page when I looked up your serial numbers

Estimated Production Year:    1937

Run Quantity:    4,000    
Grade/Model Run:    310 of 329

Estimated Production Year:    1917  
Run Quantity:    2,000    
Grade/Model Run:    127 of 329

You will note that one of your watches was a batch of 2000 made in 1917 and the other was a batch of 4000 made in 1937.

Then did you notice how the main plate has a serial number the complete serial number? Then all the rest of the bridges have a partial of that serial number and typically the serial number is also scribed on the balance wheel. The problem with manufacturing when these watches were made was that there were variations as you can see the balance bridges do not interchange because they're not of the same batch.

Basically what happens is the main plate is made the bridges are made there assembled together and then the holes for the wheels the jewels etc. are done when everything is assembled as this is the only way they have to get all of the alignments absolutely perfect. Then each of the escapement's and balance wheels are adjusted for each watch.

 

[nevenbekriev]

Yes, what I wanted to say is that the cock is part of the main plate, manufactured together with it and not meant to be interchangeable. Even if the other cock gets in place, it is not sure that the balance then will stay upright.

You should use the original cock when it exists and is not destroyed. The adjustment needed by bending it is not irreversible. It is minimal deforming that is needed. No tools are needed. I have pointed to all needed references here for the balance staff endshake checking and correctness confirmation. The only tool needed for the correction is You thumb. The cock must be fixed on the main plate, no need of special plate with holes and so on. If You will feel more confident, then measure with Vernier caliper the height of the top of the cock where the stones are against the main plate bottom when the shim is fitted and try to reach the same height when bending the cock (with no balance in place!!!) Caliper with screw for fixing is perfect.

 

 

[docrpm]

2 hours ago, JohnR725 said:

The problem with manufacturing when these watches were made was that there were variations as you can see the balance bridges do not interchange because they're not of the same batch.

Yep…This makes perfect sense. With that large a gap in the serial numbers, they were almost certainly machined on different equipment, hence one should have no expectation of any cross-batch compatibility. I’ll revert to the original bridge.

Regarding bending the bridge @nevenbekriev, I’ll give it a try, but I may have to buy some better calipers. My Vernier calipers are only accurate to 0.1mm. Not very accurate. 

[JohnR725]

2 hours ago, docrpm said:

Regarding bending the bridge @nevenbekriev, I’ll give it a try, but I may have to buy some better calipers. My Vernier calipers are only accurate to 0.1mm. Not very accurate. 

Just to refresh my memory why do we need calipers for bending the bridge?

[docrpm]

Calipers are so that I can measure how much I’ve bent the bridge (if at all). I plan on being very conservative in my application of force, and if I’m only bending by tenths of a mm, I can easily imagine not applying enough force to bend it at all. 

[nevenbekriev]

You don't need to measure anything. All You need is to adjust the caliper for the 'thickness' when the shim is placed and fix the caliper not to move. Then remove the shim and  adjust the bridge without shim as to be with the same 'thickness', and not to care what the caliper reads at all.

[caseback]

7 hours ago, JohnR725 said:

Just to refresh my memory why do we need calipers for bending the bridge?

The calipers are meant to give you some confidence if your experience doing this is limited. It can help you by giving a visual feedback/result. I kinda doubt if Nev is using calipers himself 

Edited Sunday at 07:28 AM by caseback

[Neverenoughwatches]

6 hours ago, docrpm said:

Calipers are so that I can measure how much I’ve bent the bridge (if at all). I plan on being very conservative in my application of force, and if I’m only bending by tenths of a mm, I can easily imagine not applying enough force to bend it at all. 

You are just using the calipers as a datum stick...though adjustable.  You could actually using anything to fit the space , that will give you a guide to work to. A thin piece of metal filed to size, a staight piece of old mainspring. 

1 hour ago, caseback said:

kinda doubt if Nev is using calipers himself 

A scratch mark on his thumbnail perhaps. 

18 hours ago, docrpm said:

@JohnR725 The balance bridge is from the donor. I don’t think it’s bigger…It’s probably the same diameter but the center is displaced relative to the center of the hole in the baseplate. Not by much, obviously. What I was thinking of doing was just “shaving” off the smallest amount possible from the side of the pin where I think it’s creating friction. But @nevenbekriev wanted me to wait, so…  

Reshaping one of the steady pins , will result in all of the balance components being in a slightly different place. The impulse pin and fork interaction will change.

[docrpm]

@nevenbekriev @JohnR725 @mbwatch So I’ve attempted to bend the bridge as best I could. It’s difficult for me to use my (cheap) calipers as a reference point because they don’t lock, but I did my best. My bet is that I bent the bridge by maybe 0.1mm. Enough that I could see a difference with my naked eye through my loop, looking at displacement at the end of the bridge.

With that done, I re-attached the balance wheel and did the oscillation tests again. No real change. DD is about 45 seconds, DU similar (though a little harder to measure upside down). 

In terms of the hairspring @nevenbekriev, looking closely, to my inexperienced eye, it looks as if the coils are slightly tighter on one side of the hairspring relative to the other. They don’t appear to be touching, but there is less separation between the coils.

[JohnR725]

11 minutes ago, docrpm said:

My bet is that I bent the bridge by maybe 0.1mm. Enough that I could see a difference with my naked eye through my loop, looking at displacement at the end of the bridge.

To be honest I never use calipers when bending a balance bridge as I'm checking the end shake as I do it a little at a time. Now that you've bent your bridge how Has it changed your end shake?

[docrpm]

3 hours ago, JohnR725 said:

Now that you've bent your bridge how Has it changed your end shake?

Good question. I went back and checked, and it looked like it had been reduced, but not as much as I had hoped. So I took off the balance assembly, removed the hairspring, mounted bridge, tried to bend some more, then retested. Not much change, again. I did that five more times, each time trying to apply more force. There’s now less end shake, but I’m reluctant to push it much more. As you pointed out, these bridges are surprisingly strong, thus hard to bend, thus hard to control how much force I’m applying beyond a certain point. 

In the free oscillation test, I’m now up over a minute (sans shim), which is getting us back towards where we started before embarking on the exercises of oiling and bending.

[mbwatch]

2 minutes ago, docrpm said:

In the free oscillation test, I’m now up over a minute (sans shim), which is getting us back towards where we started before embarking on the exercises of oiling and bending.

This is a positive development, especially if it holds in both horizontal positions.

[nevenbekriev]

OK, I insisted for the cock bending because now You have one problem less. Of course, I don't use calipers too. I proposed it just to give some kind of reference, which You were lacking before having tried.

The truth is that if the pivots doesn't get out of the hole stones (the balance doesn't wobble) and the free play is more than 0 ( the staff is not pressed between end stones), then the end shake, no matter how big it is, will not affect free oscillations in both horizontal positions. Oiling itself will not reduce the oscillations. Now, if You have 150 osc. in both positions and the balance doesn't rub on center wheel, the watch will run and the initial problem of this thread will be solved. I am only concerned about the hairspring position adjusting, which is another rabbit hole...

[docrpm]

Ok. So given that I had free oscillations DU/DD for roughly the same time, I reassembled with the pallet fork and bridge underneath, and now I can see two more problems. 
 

1. The arms of the balance are nearly flush with the pallet bridge. Bad. I can speculate as to why…the end shake still looks to be too much. Maybe other causes as well?

2. The balance doesn’t spin freely. In the resting position, it looks like the impulse jewel is outside the jaws of the pallet fork. Not by much, but still outside. If it needs be inside in the static position, then I’m guessing I’ll need to rotate my hairspring collet to change orientation by a few degrees. 
 

The journey continues…

[mbwatch]

18 minutes ago, docrpm said:

1. The arms of the balance are nearly flush with the pallet bridge. Bad. I can speculate as to why…the end shake still looks to be too much. Maybe other causes as well?

Hmm, if it is sitting that low I am not sure I would blame end shake (which would be to blame if you turned it DU and the hairspring touched the balance cock). If it is sitting so low that the balance rubs on the pallet bridge I would verify that the balance arms are not dished downward and also that the lower balance jewel doesn't have an issue such as being chipped.

Or the balance staff is actually too short, which would have caused your earlier end shake problems too.

If you install the pallet bridge without the pallet fork and install the balance, is your free oscillation still good or is it immediately bound up on the pallet bridge? (I have an elgin watch like that where someone in the past ground down the pallet bridge significantly)

22 minutes ago, docrpm said:

2. The balance doesn’t spin freely. In the resting position, it looks like the impulse jewel is outside the jaws of the pallet fork. Not by much, but still outside. If it needs be inside in the static position, then I’m guessing I’ll need to rotate my hairspring collet to change orientation by a few degrees. 

Yes, you'll need to rotate the hairspring but deal with the pallet bridge interference first.

[docrpm]

All consistent with my thinking! Makes good sense. 

The lower jewels aren’t cracked. However, it’s possible that when I oiled them I didn’t seat them firmly enough. I’ll double check that. 

If that balance staff is too short, that would explain a whole lot. But I don’t have a micrometer to measure. Then if it is too short, I’d have to buy an NOS one (presumably different from the 2802 I bought previously). Then we’re back close to the beginning of this discussion.  

[JohnR725]

12 hours ago, docrpm said:

However, it’s possible that when I oiled them I didn’t seat them firmly enough.

Just because I like clarifications of things? Typically on American pocket watches with jewels held together with screws their only disassembled for cleaning. Then the reassembled and for oiling their oil from the backside. As it would be extremely unlikely that you can oil the end stone and somehow pop it altogether and expect the oil the stay in place plus the little tiny screws are really not meant to be going in and out on a continuous basis as they will strip. So basically disassemble you can clean the push them all back nice and solid put the screws in and then oil from the backside like in the image below.

Small drop of oil is placed like in the figure a. Small tool is used to bleed the oil down. They do not recommend using the balance staff of the watch you're using you could use some other balance staff I usually have a much smaller staff I find it works quite nicely. Then it's a little hard to see but an image's C the oil is held in capillary action where it's supposed to be.

Then I have a link to a book that covers this and all sorts of interesting things to read about for pocket watches.

https://archive.org/details/TM9-1575

 

 

[docrpm]

Thanks for the explanation @JohnR725. I had seen images like this before, but they didn’t quite make sense. Now I get it. It’s good that I removed the jewels for cleaning, I think, since that probably hadn’t been done for a very long time. With that said, my oiling probably wasn’t effective. I can add a drop and use my oil balance staff to get it to bleed down.