Mainspring Sizing Mistake?

[Maianja]

I bought an Elgin Grade 291 pocket watch and I'm replacing the mainspring inside from its carbon steel to a metal alloy. I accidently chose the wrong length on CousinsUK and I'm worried that I made a really rookie mistake. The mainspring barrel is 16mm and the spring inside is 2.50mm x .1 and it's 21.5 inches (which roughly estimates to about 547mm). I bought a 2.50mm x .19mm x 520mm x 16. Will this mainspring still work in my watch?

[nevenbekriev]

Hi,

If the only difference is the lenght, ten no point to wary, it is OK.  You typed 'the spring inside is 2.50mm x .1 and it's 21.5 inches', which I guess is mistyping, as '.1 ' is not pocket watch spring dimension. But, if there is difference in the thicknesses, it will be a mistake.

What is the reason for changing the spring? Is it because all people do so when servicing watches? Please, if so, when everything is done, do test with the old spring too, and say here what is the difference in amplitudes with the new and with the old spring, will be interesting.

[Neverenoughwatches]

10 hours ago, Maianja said:

I bought an Elgin Grade 291 pocket watch and I'm replacing the mainspring inside from its carbon steel to a metal alloy. I accidently chose the wrong length on CousinsUK and I'm worried that I made a really rookie mistake. The mainspring barrel is 16mm and the spring inside is 2.50mm x .1 and it's 21.5 inches (which roughly estimates to about 547mm). I bought a 2.50mm x .19mm x 520mm x 16. Will this mainspring still work in my watch?

The strength of the new mainspring will be much higher than the one you removed which is more like a wristwatch strength, are you sure you measured the old one correctly ? As the length also seems too long for a wristwatch 

[Maianja]

26 minutes ago, Neverenoughwatches said:

The strength of the new mainspring will be much higher than the one you removed which is more like a wristwatch strength, are you sure you measured the old one correctly ? As the length also seems too long for a wristwatch 

Oh I should have mentioned that it’s a pocket watch, not a wristwatch. The length of the mainspring I got from the American Watch Movements manual but perhaps I was looking at  the wrong movement. 

[JohnR725]

11 hours ago, Maianja said:

Elgin Grade 291 pocket watch

http://www.elginwatchparts.com/

11 hours ago, Maianja said:

chose the wrong length on CousinsUK

Interesting I didn't know the Elgin Springs came with different lengths?

Then don't know if you took your spring out but it doesn't have your usual End supposed to have a end like this which is a standard for an Elgin mainspring

Then cousins is going to be using one of the mainsprings from this Catalog. Looks like based on the strength which is basically the heaviest spring they made 6806 would work fine but unfortunately reality with American pocket watch mainsprings whenever you get will unfortunately also have to work fine as you may not be able to find any of these.

Looks like cousins has the spring

11 hours ago, Maianja said:

I bought a 2.50mm x .19mm x 520mm x 16. Will this mainspring still work in my watch?

Then as you can see from the little exercise I did there is more to the mainspring of then the dimensions. Typically with American pocket watch springs you really do need the right end in other words you ideally need the right mainspring.

 

 

 

[Maianja]

4 hours ago, nevenbekriev said:

Hi,

If the only difference is the lenght, ten no point to wary, it is OK.  You typed 'the spring inside is 2.50mm x .1 and it's 21.5 inches', which I guess is mistyping, as '.1 ' is not pocket watch spring dimension. But, if there is difference in the thicknesses, it will be a mistake.

What is the reason for changing the spring? Is it because all people do so when servicing watches? Please, if so, when everything is done, do test with the old spring too, and say here what is the difference in amplitudes with the new and with the old spring, will be interesting.

I measured the mainspring thickness with my calipers so it could be that it was too fine for the calipers to pick up. I’ll check my American Watch Manual and see if it tells me the thickness.

I just kept reading that the old pocket watch springs made of carbon steel are outdated and I have seen people who are servicing pocket watches replace them with the metal alloy versions, so I thought I’d do the same.

When I eventually get the springs changed, I’ll check the amplitude and report back!  Thank you for your help!

 

 

2 minutes ago, JohnR725 said:

http://www.elginwatchparts.com/

Interesting I didn't know the Elgin Springs came with different lengths?

Then don't know if you took your spring out but it doesn't have your usual End supposed to have a end like this which is a standard for an Elgin mainspring

Then cousins is going to be using one of the mainsprings from this Catalog. Looks like based on the strength which is basically the heaviest spring they made 6806 would work fine but unfortunately reality with American pocket watch mainsprings whenever you get will unfortunately also have to work fine as you may not be able to find any of these.

Looks like cousins has the spring

Then as you can see from the little exercise I did there is more to the mainspring of then the dimensions. Typically with American pocket watch springs you really do need the right end in other words you ideally need the right mainspring.

 

 

 

Wow thank you so much for the links and the research that you did! I had trouble finding that info on the website that I was using. Clearly my Google Fu needs some work!

The part on Cousins UK says it’s for a 17mm barrel and not a 16mm barrel. Will it still fit? It looks like I did get the wrong length (520) and I’ll double check the end, that could also be wrong. Thank you so much for your help and research! I have a much better idea of what I should look for in future watches too. I’m still pretty new!

[Neverenoughwatches]

28 minutes ago, Maianja said:

Oh I should have mentioned that it’s a pocket watch, not a wristwatch. The length of the mainspring I got from the American Watch Movements manual but perhaps I was looking at  the wrong movement. 

You did mention thats its a pocket watch, thats why i queried the strength of 0.1  of the spring that was already inside. Seems very weak for a pocket watch

[nevenbekriev]

See, the thickness is the most important spring dimention. It is also called 'strenght', as the force it creates is proportional to 3th degree of the thicknes, so verry little difference in thickness changes the force dramatically. If You got 2.5 insted 2.6, and 520 instead of 540, that's OK.  There are 3 different strenghts in the table,  and You bought the weaker one, so may as result get lower amplitude with the new spring than with the old one, if it is correct for the movement. The end is important, but it can be changed if needed.

[JohnR725]

9 minutes ago, Maianja said:

I measured the mainspring thickness with my calipers

For mainspring the thickness a micrometer would work better.

10 minutes ago, Maianja said:

I just kept reading that the old pocket watch springs made of carbon steel are outdated and I have seen people who are servicing pocket watches replace them with the metal alloy versions, so I thought I’d do the same.

They're not exactly outdated. Sometimes they're the only thing you can get. The problem typically with blued steel or carbon Springs is they set and then there not quite worthless but just about worthless. In other words your watch will not run overnight.

Then one of the concerns is with the modern Springs for the same thickness there supposed to have more strength or power to them. But they also have interesting amusing problems. For instance both Elgin and Hamilton made outstanding alloy Springs that are still good to this day brand-new typically they come out of the package and out of the ring they'll have a beautiful back curve to them. The back curve to the mainspring is designed to supply even power to the watch. But modern springiness when you push them out of the ring and they can be all sorts of interesting shapes none of which necessarily as nice as what the original watch companies have. I had one spring words basically straight with no curve at all. So much for modern quality control.

12 minutes ago, Maianja said:

The part on Cousins UK says it’s for a 17mm barrel and not a 16mm barrel. Will it still fit?

The ring size is only really important if you're shoving the mainspring out of the package into the barrel which is not going to work for this watch at all so that number is irrelevant of no importance

oh and before I get to that have attached a PDF it shows a lot of American pocket watch springs and O get you close to what you need next time plus the ends and other stuff

now insertion of mainsprings with protruding T type ends? Typically you cannot shove them out of the ring because the T part needs to go into a hole or slot and is not enough to be on in alignment because as soon as you push the spring it's going to jump it has to actually be into the hole and/or slot.

So is basically two ways to do this I would prefer to use a mainspring winder and if you don't have one yet you'll get stuck winding it in by hand. But make sure that the T is in place no matter what because it will move around if it's not and forcing it around after the fact is not desirable.

The preferred way or at least my preferred way is with a mainspring barrel winder. We've covered this somewhere before on the group including nice pretty pictures. But that means you have to do a search so let's see if I can find a folder on my computer where I have pictures

Okay here's what your end looks like or should look like

There's an image of the winder with the spring sticking out yes it really does have to stick out for the salt to work. Plus the barrel has to be small enough to fit into your barrel.

Here is an example of the different ends so once the spring winders in the barrel he rotated around until it appears to be in the right location and then you have to Push it in the place.

Then I like to turn it over and verify it will look something like this

Then with it back on the bench before you can push it out you have to hold the T end in place either with a really big screwdriver the backside your tweezers. Then you can push the spring out and if you're successful it will stay in place.

 

 

 

Mainsprings Cas-Kar Catalog 2018.pdf

[Maianja]

3 hours ago, Neverenoughwatches said:

You did mention thats its a pocket watch, thats why i queried the strength of 0.1  of the spring that was already inside. Seems very weak for a pocket watch

I bought a micrometer so hopefully I’ll get much more accurate readings in the future, thank you!

[Maianja]

5 hours ago, JohnR725 said:

For mainspring the thickness a micrometer would work better.

They're not exactly outdated. Sometimes they're the only thing you can get. The problem typically with blued steel or carbon Springs is they set and then there not quite worthless but just about worthless. In other words your watch will not run overnight.

Then one of the concerns is with the modern Springs for the same thickness there supposed to have more strength or power to them. But they also have interesting amusing problems. For instance both Elgin and Hamilton made outstanding alloy Springs that are still good to this day brand-new typically they come out of the package and out of the ring they'll have a beautiful back curve to them. The back curve to the mainspring is designed to supply even power to the watch. But modern springiness when you push them out of the ring and they can be all sorts of interesting shapes none of which necessarily as nice as what the original watch companies have. I had one spring words basically straight with no curve at all. So much for modern quality control.

The ring size is only really important if you're shoving the mainspring out of the package into the barrel which is not going to work for this watch at all so that number is irrelevant of no importance

oh and before I get to that have attached a PDF it shows a lot of American pocket watch springs and O get you close to what you need next time plus the ends and other stuff

now insertion of mainsprings with protruding T type ends? Typically you cannot shove them out of the ring because the T part needs to go into a hole or slot and is not enough to be on in alignment because as soon as you push the spring it's going to jump it has to actually be into the hole and/or slot.

So is basically two ways to do this I would prefer to use a mainspring winder and if you don't have one yet you'll get stuck winding it in by hand. But make sure that the T is in place no matter what because it will move around if it's not and forcing it around after the fact is not desirable.

The preferred way or at least my preferred way is with a mainspring barrel winder. We've covered this somewhere before on the group including nice pretty pictures. But that means you have to do a search so let's see if I can find a folder on my computer where I have pictures

Okay here's what your end looks like or should look like

There's an image of the winder with the spring sticking out yes it really does have to stick out for the salt to work. Plus the barrel has to be small enough to fit into your barrel.

Here is an example of the different ends so once the spring winders in the barrel he rotated around until it appears to be in the right location and then you have to Push it in the place.

Then I like to turn it over and verify it will look something like this

Then with it back on the bench before you can push it out you have to hold the T end in place either with a really big screwdriver the backside your tweezers. Then you can push the spring out and if you're successful it will stay in place.

 

 

 

Mainsprings Cas-Kar Catalog 2018.pdf 138.12 kB · 0 downloads

Wow, thank you so much! For the PDF and extremely helpful explanation. A mainspring winder set is on my list of tools to purchase, but it's currently not in my budget (at least the Bergeon ones!), but I'm looking on eBay for a cheaper set to get started with. Thank you again.

[JohnR725]

3 hours ago, Maianja said:

A mainspring winder set is on my list of tools to purchase, but it's currently not in my budget (at least the Bergeon ones!), but I'm looking on eBay for a cheaper set to get started with

Main spring Winder sets are interesting in that one set isn't necessarily the answer to everything. There are some variations like if you would use it on older steel spring the arbor has to have a different hook then for modern spring. But some of the modern Springs don't fit the modern handles and then sometimes the older arbors are better. Then you're working on Seiko for instance you might need a left-handed handle.

So mainspring Winder sets the one on the left-hand side I don't like it at all but you will find them on eBay. The middle set probably 99% of all pocket watch mainsprings that's the set that I use. Then the set on the right-hand side that you can't afford. Unless you just made a lucky purchase like I did a very long time ago. It also has some minor issues like you said different handles for the older versus new springs and he almost gets stuck on vintage with both sets because sometimes one won't work.

If you do American pocket watches look for set like the one in the middle or something equivalent.