Heat treating chisels

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Im making a set of chisels from leaf springs but had a few questions.Should I heat treat them like a regular high carbon steel or do they require something different?Will hammering on them while red hot cause issues?Whats the best way to straighten them?Last edited by sn0border88; 04-21-2009 at 01:28 PM.Have we all gone mad?
Reply:try a little experimenting, i ussally heat the chisles cherry red quench in water then tapper the both ends with the torch till just showing a little blue and done,if you want to get fancy you can cap the hammer end with braze so chips dont fly off..
Reply:About 100 years ago I had to make a chisel in shop class.We used solid hexagon bar stock - I don't know if it was hot or cold rolled, but it wasn't spring steel.   I know we heated them red hot for shaping, then ground / trimmed the sides down after it was flattened out.  Heated them up until they were a "straw" color and then quenched in oil.Last edited by Road Warrior; 04-22-2009 at 12:08 AM.
Reply:From my experience automotive leaf spring material is not high carbon steel so you have to be a bit more aggressive when hardening.    First to forge or straighten heat to a full red heat.  If you hammer or forge at a dull red you risk cracking.  For heat treating heat it to cherry red.  I check with a magnet until it loses magnetism.  Quench in water dipping the cutting end in and stirring vigorously to shake off steam bubbles.  To temper,scrape the scale off the cutting end and heat from the hammer end gently until the blue colour chases down to the cutting edge.  Quench the cutting edge to prevent overheating and never quench the hammer end.  Sharpen, gloves and face shield before testing in case it it too brittle.  I have tried oil quench on leaf spring steel and the quench was not vigorous enough to harden.  I often temper to a straw/brown but that leaves the edge very hard and can snap off if the edge is abused or the chisel end is used to pry.