Sourcing a Mainspring for a 1937 Elgin Pocket Watch

[gpraceman]

My father-in-law handed me a beautiful 1937 Elgin pocket watch that was his father's.  I was able to get it apart, with a bit of difficulty.  The mainspring would not let down.  I could not get any movement of the ratchet wheel.  So, I removed the click, while holding the crown.  Nothing!  I had to coax the ratchet wheel to move using a probe on the teeth.  Then I was able to let it down.  Once I got the barrel open, it looks like old oil had essentially cemented the mainspring coils in place.

I assume that it would be best to replace the mainspring.  I measured the mainspring to be 2.06 mm X 0.16 mm X about 500 mm, with a barrel diameter of 15.5mm.  It seems to me to have a DBH bridle.  On the Cousins website, I found GR5820DBH (2.00 x .15 x 440 x 13.5 DBH End) and GR5944DBH (2.05 x .185 x 500 x 15.5 DBH End).  Not sure if the 0.185 thickness of that second one would be an issue or not, but that one seems closest.

Unfortunately, this pocket watch has a broken balance staff as well, so I will be looking for a donor movement.

Edited August 19, 2023 by gpraceman

[mikepilk]

You can find info you your watch by looking up the reference number on the Pocket Watch Database

https://pocketwatchdatabase.com/search/result/elgin/36478167

It's a Grade 315. If you select 'Parts' on the left, you can see that the balance and mainspring are common to lots of movements. 

The spring is listed as #2339, which looking in Swigart, it comes in 3 strengths :

The last three columns are length in inches, and width and thickness in mm.  
So you need about 2.05 x thickness x 500. So the one you listed, GR5944DBH (2.05 x .185 x 500 ) is within spec.

I would probably choose that strength - modern springs tend to be stronger than the old blue steel - I've had problems with re-banking. 

As for balance staff (part #2802), Dave at Daves Watch Parts has a huge stock - he will probably have the mainsprings too.

https://www.daveswatchparts.com/

[JohnR725]

1 hour ago, mikepilk said:

315

for Elgin parts link below is a better source than the pocket watch database as it tends to have a little more information

so for grade 315 it is for the mainspring is actually several of them it depends upon your serial number and you have notes at the bottom of the page as to which one is which etc. This brings up one of the unfortunate problems of American pocket watches variations for the same part number. but if we look in the Elgin material guide we find out that you're supposed to have the slightly heavier spring. Another place you can look his eBay times you can find original spring is there. then as mentioned above if you're going with the modern spring it depends on the watch this spring strengths are determined by the number of jewels but if you have a high jewel watch with a modern spring you might have an issue even if it is the size you think it should be.

then for balance staff out of the same parts book then no matter what if you're replacing the staff you want to measure the old and the new and make sure the same size that we'll avoid unpleasant things

http://www.elginwatchparts.com/

then there's something missing from the list of staffs up above. There is a dimension that you need which would be the pivot diameter. Of course you don't always get a choice sometimes

then looks like for your staff you just have pivots sizes to worry about. Notice the staff up above yours it comes in two different types with one of the dimensions being different beyond the pivots size and yet it has the same part number which is why always like to check my staffs to see what sort of variations are going to have problems with

4 hours ago, gpraceman said:

donor movement

did you notice how your pocket watch has a serial number on the main plate and may be serial numbers on other bits and pieces including the balance wheel? Ideally be better to change the staff if you going to look for a donor movement try to get it within the same serial number range. If you go with a donor movement you'll probably have to do some escapement adjustment may be because the serial numbered components tended to be matched together or manufactured together

then for the mainspring just a reminder for this type of mainspring it cannot be shove in out of the package. It either means you hand wind it in and make sure you get the T word supposed to be or a use a mainspring winder and let me show you a picture. Otherwise you going to have lots of frustration or just shoving it in because it's never going to end up well may be at least on the T brace there is a hole in it might actually catch typically with just the T they will never go where there supposed to be you have to follow procedure.

my preferred procedure is use a mainspring winder wind almost all the way in but leave a little bit out. How much out depends upon how much clearance the size of the barrel. Then rotate the winder with spring until the T is over its slot in this case. Then you do want to push it into the slot it can't just be overcast actually be in using your heavy a screwdriver of the back in your tweezers ill hold it in place when you push the spring out like shown in the image

then in the case of the Elgin you'll see something like this. Then I don't know why the Elgin slot versus the tea tends to end up in the middle probably because the whole part of the braces held by the barrel. Doesn't really matter as long as it's actually in the slot and the same with the lid the lid has to go so that it slot agrees with the protruding part.

[pent]

I have also had very good luck with ofrei.com.  They will actually help you with balance staves and mainsprings solely based on your Elgin serial number.  The mainspring I ordered in this fashion for an old Elgin I was working on fit perfectly.

https://www.ofrei.com/page298.html

https://www.ofrei.com/page318.html

[gpraceman]

6 hours ago, mikepilk said:

You can find info you your watch by looking up the reference number on the Pocket Watch Database

https://pocketwatchdatabase.com/search/result/elgin/36478167

It's a Grade 315. If you select 'Parts' on the left, you can see that the balance and mainspring are common to lots of movements. 

The spring is listed as #2339, which looking in Swigart, it comes in 3 strengths :

The last three columns are length in inches, and width and thickness in mm.  
So you need about 2.05 x thickness x 500. So the one you listed, GR5944DBH (2.05 x .185 x 500 ) is within spec.

I would probably choose that strength - modern springs tend to be stronger than the old blue steel - I've had problems with re-banking. 

As for balance staff (part #2802), Dave at Daves Watch Parts has a huge stock - he will probably have the mainsprings too.

https://www.daveswatchparts.com/

I had found that site.  That is how I knew it was manufactured in 1937.  I missed that parts link, though.  There are a few watchmakers marks on the inside of the case back, so maybe the mainspring was changed at some point.  I had heard of overbanking, so I was a bit leery about the higher strength one of those two.

I don't have a staking set (yet).  Not so sure that I want to try replacing a balance staff for the first time on a family heirloom.  So, I was hoping that I could find a donor around that age to grab the balance complete from.

4 hours ago, JohnR725 said:

for Elgin parts link below is a better source than the pocket watch database as it tends to have a little more information

so for grade 315 it is for the mainspring is actually several of them it depends upon your serial number and you have notes at the bottom of the page as to which one is which etc. This brings up one of the unfortunate problems of American pocket watches variations for the same part number. but if we look in the Elgin material guide we find out that you're supposed to have the slightly heavier spring. Another place you can look his eBay times you can find original spring is there. then as mentioned above if you're going with the modern spring it depends on the watch this spring strengths are determined by the number of jewels but if you have a high jewel watch with a modern spring you might have an issue even if it is the size you think it should be.

then for balance staff out of the same parts book then no matter what if you're replacing the staff you want to measure the old and the new and make sure the same size that we'll avoid unpleasant things

http://www.elginwatchparts.com/

then there's something missing from the list of staffs up above. There is a dimension that you need which would be the pivot diameter. Of course you don't always get a choice sometimes

then looks like for your staff you just have pivots sizes to worry about. Notice the staff up above yours it comes in two different types with one of the dimensions being different beyond the pivots size and yet it has the same part number which is why always like to check my staffs to see what sort of variations are going to have problems with

did you notice how your pocket watch has a serial number on the main plate and may be serial numbers on other bits and pieces including the balance wheel? Ideally be better to change the staff if you going to look for a donor movement try to get it within the same serial number range. If you go with a donor movement you'll probably have to do some escapement adjustment may be because the serial numbered components tended to be matched together or manufactured together

then for the mainspring just a reminder for this type of mainspring it cannot be shove in out of the package. It either means you hand wind it in and make sure you get the T word supposed to be or a use a mainspring winder and let me show you a picture. Otherwise you going to have lots of frustration or just shoving it in because it's never going to end up well may be at least on the T brace there is a hole in it might actually catch typically with just the T they will never go where there supposed to be you have to follow procedure.

my preferred procedure is use a mainspring winder wind almost all the way in but leave a little bit out. How much out depends upon how much clearance the size of the barrel. Then rotate the winder with spring until the T is over its slot in this case. Then you do want to push it into the slot it can't just be overcast actually be in using your heavy a screwdriver of the back in your tweezers ill hold it in place when you push the spring out like shown in the image

then in the case of the Elgin you'll see something like this. Then I don't know why the Elgin slot versus the tea tends to end up in the middle probably because the whole part of the braces held by the barrel. Doesn't really matter as long as it's actually in the slot and the same with the lid the lid has to go so that it slot agrees with the protruding part.

Lots of good info, thanks.  I only noticed the serial# on the train wheel bridge (36478167).  Looking again, I do see two sets of numbers on the bottom side of the balance (7816 in larger numbers and 364 rather tiny).

I have a mainspring winder set, but my largest arbor size is 3.5 mm and I measure the arbor at 5.6 mm.  Maybe I can still get the hook to engage?

Escapement adjustment?  I'm still rather new to this hobby.  I guess that I was naive to assume that I could just swap out the balance complete.  The watch did get quite a shock, as there is a dent in the case back.  All of the other pivots look good, though, as well as the jewels.

2 hours ago, pent said:

I have also had very good luck with ofrei.com.  They will actually help you with balance staves and mainsprings solely based on your Elgin serial number.  The mainspring I ordered in this fashion for an old Elgin I was working on fit perfectly.

https://www.ofrei.com/page298.html

https://www.ofrei.com/page318.html

That is good to know. Thanks.

Edited August 19, 2023 by gpraceman

[mikepilk]

Try Daves Watch Parts for a balance or donor movement.  Or search ebay - there's a big list of movements you can use the balance from.

[JohnR725]

3 minutes ago, mikepilk said:

there's a big list of movements you can use the balance

yesterday was a big list of movements but let make sure that within the proper serial number range to be compatible with this watch.

4 hours ago, pent said:

I have also had very good luck with ofrei.com.  They will actually help you with balance staves and mainsprings solely based on your Elgin serial number. 

do not know about the rest of the world as to how their material houses operate. But in this country quite a few of the material houses will deal with anybody and will be helpful if usually if you can meet them part way in other words you can describe whatever it is you need and give them the information they need to find the part. Then unlike cousins which is 100% online a lot of material houses in the US if you read the fine print will tell you that they only have a fraction of what they actually have online and you have to call email or whatever. Then what you really nice if you can find a physical material house within driving distance where sometimes you can take and show them things or to put in crystals for you and do all kinds of things the physical material houses that are in close proximity are very nice. Unfortunately do not as many material houses is a once were in the US or the world for that matter

2 hours ago, gpraceman said:

I have a mainspring winder set, but my largest arbor size is 3.5 mm and I measure the arbor at 5.6 mm.  Maybe I can still get the hook to engage?

that's because you probably haven't mainspring winding set for wrist watches. For 90% of my pocket watches I use one particular wind. Occasionally then off to break out one of the other sets and play with the handles etc. to get things to work right.

Then here's an image of mainspring winders on the left is something I never use. I'm just pointing out it does exist and I find it weird to use so I never use it. The middle one that I circled works for as I said almost all pocket watches also nice that you can wind the spring in either direction because sometimes like 18 size watches they have to go in the other way around Sunita left-handed Hambleton to them. Then the far right-hand side is your standard Swiss said except. Typically for blued steel mainspring is you need the handles of the older style as you out have the set a knock I give you pictures of that but the handles are different whether you're dealing with a blued steel spring or a modern spring. Ideally set both set the handles and a few of the left-handed watches for some of the modern watches that need one of those.

3 hours ago, gpraceman said:

Escapement adjustment?  I'm still rather new to this hobby.  I guess that I was naive to assume that I could just swap out the balance complete.  The watch did get quite a shock, as there is a dent in the case back.  All of the other pivots look good, though, as well as the jewels.

nobody else in the group worries about escapement adjustment so until it's a problem basically ignore it like everyone else. Simplistically anytime you deal with a vintage watch people like to do things to like the banking pins their movable and of course they should be moved because are movable who cares that they have a specific purpose they shouldn't be moved once there where there supposed to be. I don't suppose the other pivot on the balance is intact? Although if you going to be buying movements to get balance completes you not to get a choice because nobody's going to know sort of basically if you get the same jewel count it will probably be the same pivots size usually they had bigger pivots for seven jewel watches and smaller pivots for 21 jewel watches. Then it's good that the jewels are intact a lot of times when the balance staff breaks it will destroy the jewels sometimes you're lucky and sometimes are not.

Four Shapleigh looks like this is well I think modern enough you may be really get a balance complete it's worth trying and putting it in and see what works of it doesn't work then we'll figure out what we need to do to get it adjusted to work.

 

[gpraceman]

8 hours ago, JohnR725 said:

yesterday was a big list of movements but let make sure that within the proper serial number range to be compatible with this watch.

do not know about the rest of the world as to how their material houses operate. But in this country quite a few of the material houses will deal with anybody and will be helpful if usually if you can meet them part way in other words you can describe whatever it is you need and give them the information they need to find the part. Then unlike cousins which is 100% online a lot of material houses in the US if you read the fine print will tell you that they only have a fraction of what they actually have online and you have to call email or whatever. Then what you really nice if you can find a physical material house within driving distance where sometimes you can take and show them things or to put in crystals for you and do all kinds of things the physical material houses that are in close proximity are very nice. Unfortunately do not as many material houses is a once were in the US or the world for that matter

that's because you probably haven't mainspring winding set for wrist watches. For 90% of my pocket watches I use one particular wind. Occasionally then off to break out one of the other sets and play with the handles etc. to get things to work right.

Then here's an image of mainspring winders on the left is something I never use. I'm just pointing out it does exist and I find it weird to use so I never use it. The middle one that I circled works for as I said almost all pocket watches also nice that you can wind the spring in either direction because sometimes like 18 size watches they have to go in the other way around Sunita left-handed Hambleton to them. Then the far right-hand side is your standard Swiss said except. Typically for blued steel mainspring is you need the handles of the older style as you out have the set a knock I give you pictures of that but the handles are different whether you're dealing with a blued steel spring or a modern spring. Ideally set both set the handles and a few of the left-handed watches for some of the modern watches that need one of those.

nobody else in the group worries about escapement adjustment so until it's a problem basically ignore it like everyone else. Simplistically anytime you deal with a vintage watch people like to do things to like the banking pins their movable and of course they should be moved because are movable who cares that they have a specific purpose they shouldn't be moved once there where there supposed to be. I don't suppose the other pivot on the balance is intact? Although if you going to be buying movements to get balance completes you not to get a choice because nobody's going to know sort of basically if you get the same jewel count it will probably be the same pivots size usually they had bigger pivots for seven jewel watches and smaller pivots for 21 jewel watches. Then it's good that the jewels are intact a lot of times when the balance staff breaks it will destroy the jewels sometimes you're lucky and sometimes are not.

Four Shapleigh looks like this is well I think modern enough you may be really get a balance complete it's worth trying and putting it in and see what works of it doesn't work then we'll figure out what we need to do to get it adjusted to work.

 

So, if I stay above serial# 15914001, the balance complete would seem to be compatible.  I found another 1937 Elgin, movement only, that seems like a prospect.  Seller says balance complete is good.  It is 17 jewels vs. 15 jewels for my FIL's pocket watch, though.

The balance staff has only the one broken pivot.

I'm in the Denver area.  Hadn't heard of a supply house in my neck of the woods.