Mainspring Profile

[mcoulton]

Hello

The arbor doesn't seem to be engaging the mainspring and when I investigated the barrel, the lid just fell off on it's own. When I looked at the main spring I think I see the issue preventing the lid from closing and possibly causing the arbor to not engage with the mainspring. I've attached some photos and can you please tell me if the profile of the mainspring is correct or not. I do have a replacement mainspring and I think I'm going to install that one. Thanks in advance for any help that can be provided. 

[JohnR725]

43 minutes ago, mcoulton said:

mainspring

mainspring all by itself is pretty generic I don't suppose you could tell us the watch that goes in? Like who made the watch model number.

[mcoulton]

The mainspring is from a Piljot 3133. Hope that helps. Thanks.

[pent]

Is there a corresponding rectangular shape in the barrel lid?  I have worked on some old pocket watches that have this additional saddle which needs to be lined up with a rectangular hole in the mainspring barrel as well as one in the lid.  Major PITA if it is one of these.

[mcoulton]

Hello. You are correct Sir. Not only is there a corresponding notch in the barrel lid, but there's also one in the barrel itself. This should be interesting re-installing the mainspring! Any advice?

[pent]

Sadly, I had to struggle to install it by holding the tab in the bottom notch and winding it by hand, keeping the tab in place.  It was a massive pain and maybe someone more knowledgeable in vintage watches (mine was a very old Elgin) may have better technique.   But yes, you will have to keep that tab in the bottom of the barrel, then fit the barrel lid where the top tab sticks out.  I haven't seen this in a Russian movement, but I've only done one.

[JohnR725]

we've covered this kind of thing before on the message board. If you have a main spring winds and it's easy to do otherwise people do it by hand but it can be a pain in the ass to get everything to line up.

They vanished with the mainspring winder is you basically wind almost the entire spring into the winder leaving a little bit out then you put the little bit out and the winder into your barrel rotated until the tea party is over the slot. Push it into the slot I usually use the back of my tweezer or very heavy screwdriver verifying it is indeed in the slot. Then while holding it into the slot firm way you can now push the mainspring out and it will stay word supposed to be. If you attempt to just push it out and hope it will hold in place it will not. If you have a brand-new spring with a T tight end and to push it out of the ring it will not stay word supposed to be trying to manually rotated pastorates out in the barrel is problematic.

so the best way really is with the mainspring winder and that it goes quite effortlessly for the most part. By time we have problems with the method I describe is if the modern spring is not exactly the same shape as the original specifically how they welded the end part on then getting it into the slot can be an issue

[Galilea]

5 hours ago, pent said:

Is there a corresponding rectangular shape in the barrel lid?  I have worked on some old pocket watches that have this additional saddle which needs to be lined up with a rectangular hole in the mainspring barrel as well as one in the lid.  Major PITA if it is one of these.

Yay, what a great solve!  

[mikepilk]

This is common on Russian watches. It's a real pain as they can be tricky.

I too have a Poljot 3133 (Blue Angels), my first chrono. It's a copy of the Valjoux 7733 - I think they were made on old machines they bought from the Swiss. I have a service manual for the 7733 if you want it, it's very useful.

[Waggy]

3 hours ago, mikepilk said:

This is common on Russian watches. It's a real pain as they can be tricky.

Just about to mention this, that a lot of Russian watches use this type of spring arrangement. As you point out it can make life difficult, especially if you are using mainspring winders, hitting that little slot working blind (ie you cant see the slot or spring because the winder obscures this) when you insert the spring can make a difficult job almost impossible. I have tried marking the barrel with marker pen, but with only partial success as you have to be accurate to a fraction of a mm or just plain lucky. And once the spring is in the barrel there is no coaxing it into the slot.

So today if I come across this configuration I hand wind, not perfect, but until I find a better solution its the only reliable way to do it.

[JohnR725]

59 minutes ago, Waggy said:

As you point out it can make life difficult, especially if you are using mainspring winders, hitting that little slot working blind (ie you cant see the slot or spring because the winder obscures this) when you insert the spring can make a difficult job almost impossible.

I explained up above but maybe pictures would help. I deal with this all of the time when doing American pocket watches. The most part it works really well it's only when the replacement spring and is an weight of the same design as the original

first insert mainspring into the winder like this leaving a little bit out

here's another example of a slightly different end type

here's an example of the new spring which is currently in the barrel where the end is been riveted to the outside of the mainspring. Versus the original spring which I have setting on the outside with a end was riveted on the inside. This presents the challenge of trying to get that into the hole because they're not quite the right place. Fortunately this does not occur a lot but it does occur.

now comes the next step rotating until the protruding part is over the whole it's supposed to go in and you need to push it down until it's in the whole turned over and look on the other side and verify it actually is where it's supposed to be.

here's one example

here's an example from the Elgin spring it uses both the T and it has a hole in other words they use both but as you can see the tea party is in the middle typically sometimes the slot isn't as big as this though

now you still cannot push the mainspring out as even though it's in the whole and/or slot it will not stay you have to hold it down with something usually I use my largest screwdriver sometimes you can use the backside of the backend your tweezers

now spring is where it's supposed to be the end is in the hole or slot and you are holding it down you can push out the spring.

 

 

 

 

[Waggy]

Thanks for the explanation, I'll try this the next time I hit this issue, I always go for the largest winder the barrel can handle, which obscures the hole. Didn't think of using a smaller one... Seems so obvious now I see it!

[Neverenoughwatches]

1 hour ago, Waggy said:

Thanks for the explanation, I'll try this the next time I hit this issue, I always go for the largest winder the barrel can handle, which obscures the hole. Didn't think of using a smaller one... Seems so obvious now I see it!

You can take some tension off bewteen the barrel wall and mainspring by fitting the arbor while is has a arbor vice attached to it . Wind up and the spring t end can be slipped round into its slot.

[mcoulton]

Thanks for all the suggestions and especially the pictures supplied by JohnR725. I do have a mainspring winder and I will try the method JohnR725 has suggested and advise the group of the out come. My response may not come right away as I'll be away from the bench for a month. 

mikepilk, I'd like the service manual for the 7733 if you offering it. I've attached the service manual I have. Maybe it's different than yours. Thanks.

Valjoux-7733-7734-7736-technical-communication-service-manual-EBAUCHES-SA.pdf

[mikepilk]

30 minutes ago, mcoulton said:

mikepilk, I'd like the service manual for the 7733 if you offering it. I've attached the service manual I have. Maybe it's different than yours. Thanks.

That's the one I have.

[mcoulton]

Okay. Thanks Mike. 

[mikepilk]

Endeavour has done a walkthrough on the 31658 which is almost identical

 

[mcoulton]

Hello

Just a quick update. I managed to get the mainspring into the barrel and in the correct position. After using a mainspring winder, I marked the tab location of the mainspring on the winder barrel and the slot location on the going barrel. A black sharpie was used to mark the two spots. Then I aligned them up and carefully injected (correct term?) the mainspring into the barrel. In order to see the two markings I had to lie my face flat on the bench to properly see them. Looking from the top down wouldn't have helped me see the two markings.  I hope this all makes sense! Thanks for everyone's quick responses and helpful suggestions. 

Edited August 12, 2023 by mcoulton