Advice on heat treating needed

[brymway]

I am new to this. I have a knife blade roughed out and I need input on how to heat treat and temper it. I cut it out of an old half round file that is at least twenty years old. I know it's not the best material but I am "exercising" if you will, to learn the process. I have some leaf and coil springs for after I get some more knowledge. I have access to a home oven, an oxyacetylene torch and I can get a fire hot enough out back to do a shadetree forge while I'm building a propane forge. I know nothing of the "salt bath" you all talk about. Oil or water for quenching? ATF? Blade edge first? Tip pointing north? (crazy I know) The blade is about one inch wide by @1/8" thick, Scandinavian style bevel. Any takers?

Regards

Brock

 

[jiminy]

Old files are generally W1 or W2, (or OF - 'old file') which is in the same category of steel as the 10xx varieties, and closely approximates 1095 steel. Heat treat just like 1095, that is, basically, heat to non-magnetic (or cherry red), let it sit at that temp for 20 minutes or so, then quench in warm oil. Within 10 minutes of the oil quench put in the oven to temper ... 1 hour at around 425 degrees, remove and air cool, then another 1 hour cycle at around 425 degrees. You'll know you've got it right when the steel turns to a pale straw color. (It's easier to see the color change if you sand off some of the burnt oil prior to the temper cycles.)

There are many minor variations on the above ...different quench oils, different temper lengths/number of cycles/temperatures, etc, etc, etc ...but that's the basic jist of it.

 

[Stacy E. Apelt - Bladesmith]

Basic info by jimmi is OK. But,20 minutes for a HC steel 1/8" blade is WAY too long.5 minutes for an 1/8 blade is more than enough.Soak time on charts is usually minutes per inch of thickness,not minutes actual time.Since you don't know the exact steel type,(I consider most old files W-1 or W-2) ,quench in oil or ATF,at least a gallon if it.Quench point down while you are learning.Then temper at 400 and again at 425,one hour each.
Get a good knife making book and read up on the subject.The Complete Bladesmith,Step-by-step knifemaking,and The $50 knife shop are three everyone should read.
Only Blade Master Mark Williams does the true north thing right,none of us mere mortals can master it.I have heard of one of his blades being so perfectly aligned with the poles that when it was thrown in a southward direction it would turn around and come back at the thrower.
Stacy