Annealing a mainspring?

[PeterS]

Why would you want to anneal a mainspring? Maybe it doesn’t need annealing and I could do something else instead but I don’t know what and if annealing is the way to go I’m not sure how to do it.

I need to bend the tip slightly so it doesn’t slip. Bellow is a snapshot what needs to be done and images what happened when I was trying to bend it. I had the spring in a vice and I was pushing the end very gently. It wasn’t bending, I was giving it a push after push for quite some time being very careful and suddenly it went, felt soft like butter and I knew straight away that something went wrong.
I rounded the edges and created a taper with no issues but bending it is a struggle. I have a new one on the way but I’m not sure how to handle it.
I thought of annealing, heating it until it glows red, let it cool down, bend it, heat it until I’m not sure what colour, blue? Red? And quench it in water or oil to harden it.
Whether it would work, I have no idea. What do you think?

I’d rather not to get a NOS spring, I had one, it looked great when I took out of the container, it worked well for a day or two then there were some issues and when I took the NOS spring out it was set.

I also need to stretch the inner coil that goes around the barrel arbour. I’ve not attempted to do that yet.
You’ll see in one of the pictures below that it looks bent very nicely but it springs back. Looking at it carefully now, the jaws are not perfectly parallel, It grips the spring at the bottom well, not so much the top where I’m trying to bend it, whether that plays a role, I don’t know. I have toolmaker’s clamp I could use to grip it where I need to if you think that’s causing me the problem.

 

[PeterS]

[PeterS]

I should add, I mean annealing only the end and the coil that goes around the barrel arbour, not the whole mainspring.

[VWatchie]

I have no advice to give but would just like to mention that I tried annealing the bridle of a Generale Ressorts automatic mainspring in an attempt to reshape it. However, the result was just that the bridle lost all its elasticity. I used an alcohol lamp like this. Perhaps I heated it to much. Perhaps if you go gently!?

Edited August 18, 2021 by VWatchie

[PeterS]

Testing in progress.......

It's looking good. I heated the spring, a test spring, the one with the crack in my earlier post. I used a micro torch, creme brulee torch, whatever you want to call it. The spring was glowing red in a second, literally. I let it cool down, it only takes a moment and the spring was soft, I was able to bend it with my fingers, I heated it again, glowing red and straight into water. Now it’s solid again, you can’t bend it.
I tried it again but I heated it only gently until it was blue-ish. It was very soft as previously and I could bend it as much as I want. Then I heated it until it was blue-ish again, straight into water and it’s solid.

I’m going to play around with the coil too because it needs stretching.

As you can see the bend is quite substantial, I will not need to bend it as much.

 

[clockboy]

I anneal clock springs if to long.  Cutting the spring to the correct length I do with a diamond disc attached to my Proxon. However to drill the hole I have to anneal, also clock springs also need a slight bend on the end to stop slippage. The same principles I presume are the same for watch springs. 

[PeterS]

1 minute ago, clockboy said:

I anneal clock springs if to long.  Cutting the spring to the correct length I do with a diamond disc attached to my Proxon. However to drill the hole I have to anneal, also clock springs also need a slight bend on the end to stop slippage. The same principles I presume are the same for watch springs. 

Luckily I don’t need to drill any holes, the hole is there.
It’s good to know that others do it too, at least I know that this the way to do it. I presume you heat it again after you’ve done what you needed to do and cool it down immediately in water or oil to harden it?

[rodabod]

For the hooking at the barrel arbor, you want the material to remain in a soft, annealed state. It will conform to the shape of the barrel arbor and become “set”. Its ability to act as a spring at this section is not necessary as you are only losing perhaps 10 or 20mm of spring length. 

[PeterS]

14 hours ago, rodabod said:

For the hooking at the barrel arbor, you want the material to remain in a soft, annealed state. It will conform to the shape of the barrel arbor and become “set”. Its ability to act as a spring at this section is not necessary as you are only losing perhaps 10 or 20mm of spring length. 

I tempered it. It was very pliable, too pliable for my liking to leave it annealed. It works just fine, I’m not sure whether it will be too brittle, time will show.