Hardening a handcrafted pivot

[gkmaia]

I am fixing my Seiko Yatch. It got a mode staff pivot broken.

So I made a new one out of All Purpose Watch Repair Wire Steel from esselinger. I also have the blue steel wires as well but decided not to use it. 

Have I made the wrong decision? Should have done with blue steel?

Is there a way to harden the one I did? Should I try heating it with leather charcoal to inject carbon and then temper? Will that work?

Edited March 18, 2021 by gkmaia

[Elton]

Apply heat for a while & dip in oil will harden it. Another option is to place the metal on a piece of brass & apply heat slowly & watch for it to turn blue. 

Edited March 19, 2021 by Elton

[gkmaia]

38 minutes ago, Elton said:

Apply heat for a while & dip in oil will harden it. Another option is to place the metal on a piece of brass & apply heat slowly & watch for it to turn blue. 

Great Thanks!! will do that.

[nickelsilver]

I doubt that they would sell an unhardenable steel, so no need to "inject carbon".

If you want to harden steel, the typical alloys that a watchmaker might use would be oil hardenable or water hardenable. At watch size parts either will harden in oil just fine, so don't fret about knowing which type you may have. It needs to be heated to its critical temperature, which for practical purposes isn't a number but a color- you want to get it a dull orange color, then immediately drop into oil (about 0.5 liter is good). It can be pretty much any oil, but thinner is better than thicker. Now the steel is completely hard. To test if it did in fact harden you can try to cut it with a fine file (like a 5 or 6 cut). The file should slide and not bite. Obviously try this on a piece of your steel that hasn't been made into a part yet! Once it's hard, you need to clean off the scale and black color, then heat it in a pan of brass filings or fine sand, normally over an alcohol lamp, and bring it up to a blue color. Now it's tempered. If left in the full hard state it will be too fragile, tempering reduces the hardness, while increasing toughness.

 

Once it's blue you can clean it up in your lathe, the blue comes right off with fine grinding or polishing paste.