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I Forge Iron

Another heat treating,tempering and file question.

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i have been recieving advice and constructive critic over the weekend in regards to making a combat knife out of a file.  so I want to pitch my understanding/idea to see if I have the concept down:

if I dont want to anneal first, I can cold stock removal shape the blade and then heat it to critical, quench it, then temper it?


or could I JUST temper it if i did not comprimise the hardening ?


thanks for having patience with me guys.  I love you all.

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Keep it cool as you are grinding it in the hardened state.  That makes it easier to get it correct.  If you turn it blue while grinding you've ruint the temper and will have to normalize and reharden.  Follow it up with a good dark straw temper (you'll loose some edge holding but gain strength).  Start at 375F and work up to the correct color (done that way unless you really trust your oven).

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TEMPER FIRST, a file's starting hardness makes it extremely brittle. Dropping it, especially after ground thinner, onto concrete will often shatter it. If you draw it back to the temper you want to end up with it will have the toughness of the final blade---and for a combat knife should be able to withstand being dropped!

Of course after it's tempered you must keep it good while grinding on it. We used to immerse in water after every pass and hold it in our hands---if it was too hot in the hand then it's not too hot for the temper---generally.

Now if you are going to do the full re-heat treat at the end of grinding start by drawing the temper WAY DOWN so any drops that occur will not hurt it and then normalize to release grinding stresses and then harden in warm oil and then temper 3 times to your final temper. You will not need to triple normalize as *no* grain growth occurs in cold working.

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