Waltham - which mainspring?

[PeterS]

I have a Waltham pocket watch here. When I search for the serial number in pocketwatchdatabase.com it brings up grade 621 and movement size 16s
The details can be seen here: https://pocketwatchdatabase.com/search/result/waltham/22323804
I contacted an Ebay seller who was very helpful, he worked out I needed mainspring 2227/2267 and he did not have one. They can be obtained from Ebay but I'm interested how to work it out for myself next time I need one again. There are five different mainsprings for the size 16s:
https://pocketwatchdatabase.com/reference/mainsprings

I could measure it when I get to work on it but it would be easier to have the mainspring ready.

Edited March 22, 2021 by PeterS

[WellAdjusted]

It really helps to have access to one of many manuals for American parts and materials. You can find Marshall Handy Manuals, Swigert manuals, and many others here and there around the Internet. I consult the old Marshall parts interchange all the time. You'll also find old Waltham parts lists and mainspring charts online, too.

Many parts suppliers (like Otto Frei) basically copy and paste the info from those books into their descriptions, and that would be a good place to start for American mainsprings.

As for figuring it out, once you narrow it down to the brand and size you funnel into the specific model (a Waltham 16s Model 1908 in this case), and then you should see at least 1 option. Often you have a range of strengths available for models that varied in their jewel counts.

For a Waltham 16s 1908, you could use those you mentioned or 2218. They vary slightly in thickness (strength) but are otherwise identical.

As a related tip, Cousins UK sells new Swiss alloy mainsprings for many old pocket watches. If you download the Generale Ressorts pages from their webpage, you can get guidance for many of the common American mainsprings. Brand new mainsprings from them are often cheaper than vintage NOS ones from eBay.

[PeterS]

Many thanks for the info and tips.

I wish I saw your post earlier on. I ordered the NOS 2227 from Ebay. I guess the grease that was applied on the mainspring would have degraded by now and I’ll have to clean it and put new grease on it.

I’ll download the Generale Ressorts catalogue this evening and I’ll try to work out how to find the brand new equivalent. Even though I have a replacement on the way now I’d still like to get my head around it for future repairs. I may be asking more questions but I’ll do my research first.

[PeterS]

What I've found so far is that I can get good info from pocketwatchdatabse. It looks that the year of the model is important and also the size or grade.
I can then google Waltham 621 1908 mainspring or Waltham 16 1908 mainspring. I get several results mainly from ebay leading me to the 2227 mainspring. I can look up 2227 in pocketwatchdatabase and that gives me measurements 25, 2.8, 0.18. In the GR book there are four entries for 2227, all have same measurement except the thickness 0,16, 0.17, 0.18, 0,19. The 0.18 is GR 6978 TR and I get no reuslts when searching for it on Cousins site. The 2218 you mentioned is GR 6991 TR (thickness 0.19 and other measurements are same) and it's exactly the same as one of the other entries for 2227 in the GR book, also listed as GR 6991 (page 195). The GR 6991 is available but not 6991 TR.

I'm not entirely comfortable relying on ebay results to lead me to the 2227 number.
The GR 6978, 0.18 thickness is not available, how do I know the 0.19 (Waltham 2218, GR 6991 TR) will be a good substitute for the 0.18? Also the 0.19 GR 6991 is available but not GR 6991 TR.
The length is also slightly different. Pocketwatchdatabase lists 25 inches = 635mm, GR 6991 is 640mm.

[JohnR725]

Unfortunately with American pocket watches obtaining parts Ahead of time is problematic. It's usually nice if you can measure whatever is in the watch and compare it to whatever you think is supposed to be in the watch. Then if they are in agreement you can get the part. Another thing that pops up even with a part number the part number may actually have size variations which is why it's helpful to measure whatever is in their.

I snipped out a section of one of the books that's listing mainspring and see you can see what one of the problems is. Yellow part number and have a mainspring became in various thicknesses. Except conceivably today we'll be lucky to find one house.

Also pocketwatch database indicates the total production of this movement was 750. That's a rather limited quantity compared to what I normally see I don't suppose we can get a picture?

[PeterS]

Thank you very much, that's an awesome chart!
This makes it very easy to identify the mainspring. Pocketwatchdatabase gives you the year and size and from your chart it is so easy to see that it's the 2227 that I need. It was surprisingly easy to get the 2227 on ebay. I don't know what thickness it is yet, I'll measure it at some point. Strangely enough, pocket watch database only lists one 2227 mainspring with thickness 0.18 for the 16s and your chart lists 5. In all honesty, it won't matter that much, the owner doesn't use it and it will be better than the slipping mainspring that's in now.
I just came across the Marshall Handy Manual that was recommended to me in pdf format so I'll have to check that out when I get the chance.

I was pleasantly surprised when I found that they only made 750 pieces. They did 2 runs, 500 hunter cases, that's this one and 250 open faces. It's lovely, I'm thinking of making a video.

Enjoy the pictures and thanks again for your help.

Edited March 24, 2021 by PeterS

[WellAdjusted]

To loop back to the issue of variation in length and thickness, we modern types have less choice with new mainsprings than the old-timers did. Mainsprings for the big brands were available in many thicknesses.

For new mainsprings, there might only be one thickness option. The length is often off by a bit, too. I've suspected that companies like GR are finding "sweet spots" where one spring can suit many models (such as how some old 18s Illinois and Walthams use the same GR springs).

Small variation in length, for all practical purposes, is not a very big deal for the watch's behavior, assuming the wound is wound once a day and you're not needing a long run time. If you look at the long history of aftermarket, third-party springs, they have always been more likely to nail the spring's height and thickness (crucial parameters!) than the spring's length.

The thickness, though, will lead to too low or too high amplitude if it isn't right. Unless the watch has fewer than 15 jewels, I use middle-of-the-road strengths. Spring force is the cube of thickness, if I recall right, so the functional difference between .15, .17, and .19 is pretty big!

For what you have, either the .18 or .19 would be fine. I'd pick the .19 for a 7-jewel version, but .18 and .19 should both perform well for yours.

 

[PeterS]

I'm not quite sure what the thickness is, I measure it 0.21 but it's still in the container and I suspect that if it was unwound it would be less. The more I get to the centre the thicker it gets, I think the curve adds a little.

Thinking about it, even measuring the old spring that is currently in the barrel may not be what I need as I will not know whether the spring has been previously replaced and if it has, the question is whether it has been replaced with the correct mainspring.

It's going to have come out of the container as this one does not have the shim like the modern mainsprings do and it will need fresh grease anyway so I'll measure the thickness at that stage.

This is what I have:

 

Edited March 25, 2021 by PeterS

[JohnR725]

Your picture looks interesting? It almost looks like a blued steel spring? That would mean it's an older spring at least it looks clean and dry sometimes in the older spring as they would get rusty. When you take the old spring out of the barrel we can tell if it's an original spring because the original spring is usually have initials at the end that hooks on the barrel.

Then one of the problems you're having with measuring the mainspring is you should have it out of the package and out of the barrel and you should use a micrometer not of the near caliper. The near calipers have issues with mainsprings and art absolute straight and parallel with the jaws so you'll get some measurement discrepancies which it typically won't get with a micrometer.

Then if you have imparted be nice to see what the barrel looks like? If it's the thin-walled steel barrel then getting at the hook could be a challenge if the mainspring is shaped correctly. waltham further steel barrels requires the end of the spring to be bent in a specific way and the whole needs to have a taper. So if you have a steel barrel all find the previous discussion or a picture for you so we can verify that it indeed is correct otherwise your spring is never going to hook unless you just like.

[PeterS]

This is the blued spring. It doesn't look it from the top but you can see it from the side, it's 'new old stock'. It looks clean when you see like this or even when you use a loupe but when you get the macro lens nothing ever looks clean. Click or tap on the picture and then zoom in, it's quite a large jpeg.

I'll be taking it apart in a week or two and I wonder what I'm going to find inside. At this moment, it's slipping. I assumed that if I get the 2227 for this movement it would be straight forward but we'll see when I take it apart. Getting the mainspring into the mainspring winder will probably be a challenge too. They are good with the 'unbreakable' springs but when I used it on the blued springs it was a little tricky. I'll post pictures as soon as I disassemble it, I will most likely need advice.

 

[Malocchio]

This is a Waltham, my first and so far only pocket watch. 

https://pocketwatchdatabase.com/search/result/waltham/27383682

I took the mainspring barrel apart and did some research on possibly getting a new mainspring. So I guess the correct spring would be 2237 since this is a size 12 colonial B. That spring should have a hole end but the spring I just took apart has a tongue. 

I put a piece of paper for some contrast. So is this supposed to have a mainspring with a hole end? Not an exact match but closest one to the 2237 I could find from Cousins is this one https://www.cousinsuk.com/product/up-to-165mm-height?code=GR4755TR