steels and heat treating without a pyrometer...

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Aug 20, 2013
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Newbie here, and I apologize in advance because I'm well aware that this subject gets beaten like a dead horse and surely annoys the veterans out there to no end...

I am interested I making my first attempt at making a knife. My main hobby is woodworking, and I have several plane irons and chisels in both O1 and A2 Cryo steel. I also have a few ESEE knives in (IIRC) 1095 steel that I am very happy with.

Anyway, seeing as how I have a good sized 1 1/12hp 6x80 edge sander, drill press, sanding drums, mill files, Lanskey setup, DMT Diamond Stones, Norton water stones, and a plethora of Silicon Carbide Wet/Dry (+ plate glass)...AND I do love me my knives, I figured I'd have a go at making a knife. Knife making has been an interest of mine for some time, but alas, with two FT jobs, a wife, and three young hellions; I have MANY more interests and prospective hobbies than either time or money.

Here are my questions:


1) O1 vs A2 vs 1095?
From what I understand (at least pertaining to plane irons and chisels) O1 is finer grained, takes a keener edge (than A2) but is less wear resistant, and as such may require more frequent honing. A2, on the other hand, is tougher and more wear resistant, but due to the formation of carbide molecules during it's heat treatment, cannot take or hold as keen an edge (cryogengically treating the steel at -300*F for a period of time before tempering alleviates this somewhat, by I seem to be fresh out of liquid nitrogen). As for 1095, other than a little I have read online and the fact that I'm a big fan of my ESEE knives, I have no experience.​

2) Heat treating and critical temps
While I do not have a forge, by father-in-law (contrary to the norm, I have AMAZING in-laws) has been a professional ferrier for 30 years, and is DAMNED good at his craft. He has a small propane forge, anvil, and an assortment of blacksmith tools used by ferriers. Unfortunately I don't believe he has a pyrometer with which to measure what temperature I am at when heat treating. Is there a "color" indicator I can look for to determine the steel has reached critical temp? Would attaching a rare earth magnet to the underside of the steel and watching for it to drop-indicating demagnetization-be an acceptable method? Also, for the quench, I have heard peanut oil is frequently used as a quench for O1, due to its high flash point. A2 is air cooled, so that is simplified somewhat, but IIRC a stainless steel foil wrap is recommended to prevent decarburization when heating it (is this good practice for all three steels?). Lastly, as I have a limited amount of initial overhead that I can get away with before I get evicted to the couch, I don't know that I can swing buying a specialized quench oil (Aldo's?)-although I haven't yet priced it so perhaps... In this instance, if I were to go with 1095, would peanut oil work as well for an oil quench? Room temp to quickly drop the steel <1000*F or slightly heated (125*F-150*F) to prevent warping the knife steel?​

I know I wrote a bit of a book here, I apologize again for dragging up the SOS, but thanks in advance to all who share any tips, advice, or knowledge. I have tough skin, so criticism or correction of inaccurate info is welcomed as well. I'd rather do this right the first time, that blunder through it based on misinformation!
 
From what I have read a farriers forge is not ideal for heat treating. I've read that it is designed to get the shoes up to temperature fast and does not give good results when trying to maintain a set temperature. Your 1095 will require a short (@ 5 min.) soak a couple of shades of red above non magnetic before normalizing (if you are forging). This is hard to do with a coal forge and a baffle where you can see the blade very well. 1095 is probably easier than O-1 and certainly easier than A2 to heat treat.

A rare earth magnet will demagnetize if you get it too hot. I use a mechanics pick up wand and get it just close enough to feel the tug from the magnetic steel. I do not know if A2 is magnetic?

A better steel would be 1084. You will need to get it a uniform shade above non magnetic then quench. Normalize if forging.

You can do stock removal and send the blade(s) out for heat treat. This will improve the likelihood of a good HT, therefore good knife, and you can use A2.
 
Thanks for the info! Didn't realize I double posted, computer must've glitched. I don't plan on forging...at least not yet anyway. While my father-in-law has a good anvil and proper smithing hammers, tongs, etc...it's a 60 miles drive to visit. If the interest continues to grow, I'll wait to acquire my own tools and a proper forge (your comments regarding farrier forges makes sense, his resembles a commercial version of a DIY "soup can" forge. While I'm sure some degree of control can be attained by titrating the propane flow, I'm sure it isn't enough to dial in specific temps to HT). Thanks again for the info, might give it a go with what I have available now, and if I keep at it, look into a proper forge or pro HT in the future.
 
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