Jump to content

Looking for a Mainspring

jdrichard
 Share

Recommended Posts

jdrichard Distinguished Member

jdrichard

Posted
Posted

I just picked up a Hamilton 974 and am looking for a Mainspring. Hunter and could not find the dimensions. I was successful with replacing a mainspring for an old german watch using a Cousinsuk generic one...want to do the same for this one5cf05e07ccf029007ff89361d99eca39.jpg

From Canada

jdrichard Distinguished Member

jdrichard

Posted
  • Author
Posted
I just picked up a Hamilton 974 and am looking for a Mainspring. Hunted and could not find the dimensions. I was successful with replacing a mainspring for an old german watch using a Cousinsuk generic one...want to do the same for this one5cf05e07ccf029007ff89361d99eca39.jpg

From Canada

From Canada

JohnR725 Distinguished Member

JohnR725

Posted
Posted

I've uploaded image with the specifications for your mainspring. Just remember when you're looking for a generic spring it has to have the right end to fit American pocket watch. Then typically the modern White Springs for the same thickness are stronger than the original ones. Personally I always like to remove the old spring and measure that just to verify it does actually meet the specifications that you find the reference books because occasionally there's variations.

hamilton ms974.JPG

  • Like 1
jdrichard Distinguished Member

jdrichard

Posted
  • Author
Posted

Thank you very much. I will get better at this with experience and a few (I hope) failures. I will measure the spring and see if I ordered the right one.

From Canada

JohnR725 Distinguished Member

JohnR725

Posted
Posted

The width of the spring was fine I looked at the cousins website before I posted my last message to see what they had.

All the dimensions in real life are critical but almost lucky to get what you can get now. So slightly narrower isn't an issue there tends to be some variation depending upon who manufactured the spring anyway. Length usually isn't an issue unless you go extremely long or short. Too short you lose running time too long it gets to be hard to get into the barrel and if you fill the barrel up you have no running time. The thickness or strength of the spring is the problem today. The white Springs are stronger than the blue for the same size.

Availability is an interesting issue. I'm attaching an image for an example. So originally you might have had several different sizes of spring for the same part number. Usually the thickness was the difference. This would correspond to the heaviest one would go in a 7 jewel watch the lightest In a 21-25 jewel watch. Today if you're lucky to get one the spring possibly to light for a seven jewel and often too heavy for a high jewel watch.

Then the reference I was using is this book "The E & J Swigart Co., Illustrated Manual of American Watch Movements" Which you can get is a physical book and as a PDF. So besides the parts listed for various pocket watches there's a section on mainsprings. Depending upon which company the mainsprings are listed by the model of watch it goes in other times it's by the part number.

ms-prob.JPG

syfre WRT Addict

syfre

Posted
Posted

The most important is the termination, modern mainspring don't used T-End style; don't think you can find that on cousins uk. Hamilton #318 mainspring are easy to find on ebay us.

  • Like 1
 Share
Go to topic listing

  • Recently Browsing

    • No registered users viewing this page.

  • Topics

  • Posts

    • TimeWerks
      Omega sweep second pinion friction spring - correct tension IS important

      By TimeWerks · Posted

      Thanks for this post MikePilk, I just came across a similar problem with an Omega 1022.  The problem I had was the seconds pinion spring was bent out of shape and did not even engage with the wheel properly, so the seconds hand was not moving at all. (no power loss though :) I removed the automatic module so I could access the spring and work on it. Once I bent it back close to the right shape, I experienced the same problem you reported about power loss.  Many tweaks later, and the seconds hand is moving properly again, with amplitude back to good numbers again. Cheers
    • caseback
      Clock newbie

      By caseback · Posted

      After cleaning up the pivots, I made bushes on the lathe. At this point I've pressed in 6 bushes (3 sets) and the wheels turn smooth. What I can also tell you, is that I'm not looking forward to final assembly. Getting the pivots aligned seems to get exponentially more difficult with each wheel that is added.
    • JohnR725
      Greetings from Whidbey Island.

      By JohnR725 · Posted

      Islands are interesting places to live depending upon their size and other factors. This is a bigger island and it has a bridge to get there at least on one end. It's also big enough that you don't have to go someplace else to get things typically. It can be a problem if you get a job in Seattle though. Yes I've known of people who commuted from the island to Seattle for a job and I don't quite remember how many hours it took but it took a long time. So basically islands are nice if you don't have to leave very often.
    • VWatchie
      What's your thoughts on this Rolex Sea-Dweller, ref. 16600, calibre 3135 project?

      By VWatchie · Posted

      Thanks @JohnR725! Everything you say makes a lot of sense and is encouraging to read.
    • JohnR725
      What's your thoughts on this Rolex Sea-Dweller, ref. 16600, calibre 3135 project?

      By JohnR725 · Posted

      isn't it nice to have a decent case open or when the case doesn't want to be opened? In the case of a Rolex watch that supposed to pass specific water resistant testing you probably do need to tighten the back down. But they shouldn't be tightened so much that they risk stripping the threads out. Then the other problem that comes up is the gaskets can start to disintegrate and then getting the back off can be quite a challenge unless you have a really good tool and perhaps some penetrating oil to loosen things up. Yes really nice case marking. When I was in school we were taught to mark the cases and  the American watch and clockmakers Institute even had a? So if you joined at one time they would give you an identification number. They were explaining or giving an example of if the watches ever found in you have a unique number they can perhaps figure out the history of the watch or identify the body it's attached to for instance not that that probably comes up that often. So you got a unique number and even made a special metal stamp that you can purchase. It wasn't a super big aggressive stamp but still it left a mark in the back of the case. Then I heard from people at work on Rolex watches they were using a felt pen indelible but later on they decided that was bad because apparently the ink could release  chemicals although it seems like once it's dry that shouldn't be an issue. Then of course today was nice is you can keep computer records sealed have to mark anything at all I personally find it's best to leave no reference behind that you were even there. Especially when you have a beautiful watch that has no markings at all and now it has your scribbling all over it not good typically if there is a typical and watch repair?  a lot of minor repairs you don't need to do a complete servicing. But beyond a certain point you're going to have to take apart a lot of stuff you're going to disrupt the lubrication even if it looks perfect right now and yes you might as well just go ahead the service the whole thing. also in a watch like this where a lot of things seem to be going on the complete service would be better then you'll know exactly where you stand versus dealing with unknown mysteries for prior repair.
×
×
  • Create New...