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[Vince2]

Hi, I need to bend the kickstart lever to clear high level exhaust pipe. Q. Once heated and bend should it be left to cool down or quenched in water? Vince

[papasmurf]

Hi, I need to bend the kickstart lever to clear high level exhaust pipe. Q. Once heated and bend should it be left to cool down or quenched in water? Vince

That depends what the kickstart lever is made of, I suspect in most cases it will snap.

[stinkwheel]

Don't quench.

I'd imagine it's not high carbon steel anyway so quenching won't do anything to the internal structure of the steel but it could cause stress fractures. Quenching only works to harden high carbon steel if you heat it to critical temperature anyway which is a little over 700 degrees C (incandescently hot and up to a temperature where it's become non-magnetic). Probably hotter than you'd be doing to bend/forge it. It's also normally quenched in oil unless you're making super-hard tool steel pieces out of water-hardenable steel like lathe cutting tools. If you did succeed in hardening it, you'd then need to temper it back a lot because hardened carbon steel is brittle and could well snap leaving you with shards of kickstart embedded in your leg.

Normalising by heating the whole piece then allowing it to slowly air cool a few times would help reduce internal stresses caused by the bending.

Interesting video on the properties of non-hardened, hardened and tempered steel here:
https://www.youtube.com/watch?v=6jQ4y0LK1kY

[Vince2]

Hi, thanks that confirms what I suspected, intend to heat in forge then cool naturally. Vince

[Bullet Whisperer]

I have heated several red hot very quickly with the oxy / propane torch in the area to be bent, bent them and the plunged into cold water to minimize any damage to the chrome either side of the bend and have had no breakages to date.