I would like to address this to our repair people and watchmakers that have the equipment to test and have made the test or can make the test:

If one gets a watch in for repair that has an old or original mainspring AND the movement appears to be relatively clean ....

Before anything else is done to the watch like running it thru the cleaner and cleaning and inspection.....

And all that is done to the watch is replacing the mainspring....

Have you ever took it's pulse before and after with the mainspring replacement ??

Have you personally found that it now is within the beat required to be a reliable timekeeper ??

What the question addresses is this :

Can a mainspring lose it's resiliency over a period of years like an oil loses it's viscosity??

I'm not talking about a "set" in the mainspring, I'm wondering if the metal in the mainspring can lose it's ability to impart total power to the train even though it's coiled effect "should" apply full power to the train.

I am not experiencing problems with a mainspring and am not looking for troubleshooting advise, I just want to know if the mainspring can lose some of it's abilities thru metal fatique.

Has anyone made this testing on a mainspring alone ?? I do realize that all the parts need to be maintained and COA'd to get max results, but again, will a mainspring lose it's resiliency since there are a whole lot of watches out there with an original mainspring in them that is 50-100-150 years old.

regards,
bb

Buster-

While not very common for me, I have had instances where the mainspring did not have enough power to let a watch run correctly. I replaced the mainspring with a new one and it fixed the problem. A lot of times the mainspring is very small in diameter after being uncoiled. Now, the other problem here is also that over the years the mainspring may have been replaced with a mainspring that was the correct size, but not the correct strength of spring, causing this problem too. Here is a pic of a Elgin mainspring from a movement I just got in. From left to right, the barrel, the mainspring that was in the watch, a new mainspring. This old mainspring may have power left to where the watch will still run correctly, but my guess after looking at it is that it will be weak on the power end of the watch.

Jared

Buster-

Also check out this information on springs. especially the degradation section. Hopefully this helps.

Thanks,

Jared


Link

The "physicals" of steel when deformed stay about the same. But "old steel" can take a "set" from elastic deformation and when wound is hardly deformed at all, losing therefore it's "strength".

The two springs you see in Jared's photo show the effects of what we old physics psycho's call "Elastic", or "Plastic" deformation in metals. When the spring is left fully wound for long periods of time, the early rolled steels would "relax" on the stressed side and lose a considerable amount of "Power". This is because when the spring is fully wound, it forces a "stretch" stress of the outer face of the very long grained structure of the spring steel. This was common among all "older" watches. Those we find with "good" springs usually were put away working and "ran down" (taking the stretch stress out before elastic deformation could occur).

The newer "White Steel" springs are a completely different animal which have very short grain structures and if micro-sectioned show a long overlapping series of short crystalline structures that do NOT "stretch" much due to their very short length and physicals.

When an "old" spring breaks it is a simple fracture, when a white steel spring breaks it is a de-lamination sort of like a "green stick" fracture.

Thank you !

I was thinking that it might...

So a mainspring over a period of time can lose some of it's resiliency and in retrospect

If one gets a watch in that is "wound tight" and not running, then one would be best advised to have the mainspring replaced since steel will relax from being stressed and will lose some of it's power or resiliency that it was designed to impart

Brilliant responses, and I for one will take note of any future watches, as we all should, when and if we find a watch in this type situation. Thanks again

regards,
bb

From experience if you examine the mainspring in Jared's picture that has taken a "set" you will most likely see the surface has started to fragment and the next thing that happens is why we have safety pinions on center wheels.....

Regards, John

I did a little post on the safety pinion. The picture below is part of that at;

https://ihc185.infopop.cc/eve/f...701066233#6701066233

Nicely done David!

Hi Buster;

When it comes to springs, (and over 37 years of gunsmithing I've literally made hundreds of them in all shapes and sizes) they can become very different from a power standpoint depending on use or neglect.

For example, a pistol magazine sitting idle and full of ammunition for say a couple of years may indeed become weaker, but only by "taking a set", and I know that's not what you mean.

Now, if you take that same magazine without any ammunition in it at all, no matter how long it sits idle, will retain all the power that was inherent in that spring when it was made. A spring can only become weaker through use, or through neglect such as rust, damage etc.

Finally, in a working environment, the longer you subject a spring to the forces required of it to properly function 1oo% of the time, the weaker it will get over time.

Old muzzleloader firearms such as the Matchlock often utilize brass leaf springs in their locks, and brass is the only spring material that I know for certain will lose power over many years of use.

I hope that helps Buster.

Bud

quote:

I just want to know if the mainspring can lose some of it's abilities thru metal fatique.