Coil spring straightening

[Twobit]

Question: if I heat up a coil spring in order to straighten it, can I then heat treat it back to springiness after getting it in the desired shape?

[sammy the blade]

You may be able to do it but I don't think I could without screwing it up. I'm sure Bill will know.

[Twobit]

I'm having success shaping it cold, actually, so I don't think I'll risk it.

[Bill DeShivs]

Unless you can properly heat treat the spring, the answer is "no."
And, from your question, I can tell you can't properly heat treat the spring.

[john]

Hi Bill, what is the proper way to do it?

[Twobit]

Bill, what I wanted to know was if it would take a proper temper again after being annealed and the how of re heat treating it if it could be done. I'm quite capable of following directions I just need to know what to look for, color -wise as I heat it.

[Bill DeShivs]

It can be done. Unfortunately, small coil springs are too thin to reliably heat treat without a heat treat oven. The steel heats and cools too fast without a controlled atmosphere and even heating is a problem.
In theory, if the spring is common high carbon steel- heat to cherry red and quench in water (oil is too slow for tiny springs.) Temper to even blue and let air cool.
I have done it, but the failure rate is extremely high.

[Twobit]

Bill, this is about 3/32" in diameter stock, about the size of a round stock kick spring, which is what I'm thinking of using it for on my Taiwanese rebuild. I've already gotten it pulled into a very shallow arc of about four inches in length. I figure I'll need another similar length to make kick springs for both knives I'm modding.

[Twobit]

I have lots of these springs available at my work as they come as part of a bendix assembly . We discard this spring and replace it with a lighter weight one for use in the gear assembly we need it for.

[boots]

Question: if I heat up a coil spring in order to straighten it, can I then heat treat it back to springiness after getting it in the desired shape?

OK, I have to ask, what did you do?

[Bill DeShivs]

3/32 can be successfully torch heat treated, Quench in canola oil.

[Twobit]

Question: if I heat up a coil spring in order to straighten it, can I then heat treat it back to springiness after getting it in the desired shape?

OK, I have to ask, what did you do?

Boots, I used two pairs of lineman's pliers and just grabbed on in two places pretty close to each other and twisted it straight, so to speak.

[Bill DeShivs]

I thought you were talking about little coil springs, like used in knives.

[Twobit]

No, Bill. Wanting to make a kick spring out of a coil spring straightened out, more or less

[Bill DeShivs]

Same process as above. Get it shaped, harden, and temper.