flame-harden pneumatic breaker chisel?

Question

Hi folksMore saga of the lost wax castings with the extra ceramic to dig out.Needle descaler worked wonderfully.  And much less dust.But zero dust and most work done - big several-kilo pneumatic breaker.Very controllable - real "big pussycat" of a machine.  Rounded smoothchisel end - just don't catch the casting full-on.  But is soft soburrs over when breaking up metal infiltration into ceramic plug.Able to flame-harden chisel?Thinking roaring oxy-acetylene cutting torch preheat flame (enough forcut 25mm plate!), very rapidly heat tip to red hot and quench in oil.Part oil-quench, part self-quench.  ie. "flame harden"(?)Good idea?  Bad idea?  Temper makes it OK idea?  Temper 300C ("straw"colour patina)?These chisels have been used to break-up red-hot dross in ladles -there is no previous hardness to loose.Richard Smith

dcaster · Accepted Answer

Assuming that there will be a need to break up red hot dross again..........Maybe wrong assumption................ But I would consider getting new chisels and only using the new chisels on cold items. Keep the old chisels to use on red hot dross.

Dan

beecrofter · Answer

Roughly with a shell hardening tool steel heat until a magnet does not stick, hold the temp to do about an inch of the tip, use fuel oil at room temperature as the quench,dip the tool and stir slowly- a couple gallons in volume won't flare up on you, test the hardness with a file it should not skate over the surface as if you were filing glass but it should baely bite into the surface, draw at about 450 if too hard.

flame-harden pneumatic breaker chisel?

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