farmed out heat treatment

N

Nebulae

Joined
Aug 24, 2009
Messages
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Do any of you find that customers prefer knives with professional Heat treatment, or your own. I ask because I was thinking about buying a fixed blade on the forums, and it seems to that from the pictures I can see for the most part if the build quality is o.k or not, grind lines, finish etc, (there is not a lot of potential for terrible quality like in a folder) but I cant see the heat treatment. If it is heat treated professionally, I know it will be tough and hold a good edge, but if it was done in someones backyard its a mystery. I know this is not an issue for established makers, but I'm not sure if I would trust some peoples heat treatment. Also I will NOT buy a blade if I do not know the exact HRC number
 
the vast majority of my customers just glaze over when I bring up hardness, HT, or even alloy... and don't bother talking about modulus of elasticity, retained austenite, carbide size, plate versus lath martensite. I still get "is it stainless?"
 
If a competent maker is heat treating his own work, it is heat treated professionally.

Problems do arise, and it is a mistake to assume that steel heat treated at a heat treat shop is necessarily optimal. Most HT facilities want to reduce warping, mix relatively compatible steels, and minimize risk of cracking, while minimizing waste of things like nitrogen (gas and liquid). Which are all good goals. But sometimes do not align perfectly with optimal HT.

I also wouldn't assume it isn't a concern with established makers.

And lastly, there is much more to a good heat treat than just achieving an HRC number.
 
As for knowing a knife was done by a pro shop like Peters' or Bos, I tend to agree, that removes a lot of the room for worry; however...

Many custom makers specialize in one or two alloys and have their HT dialed in pretty well. The better ones generally have no problem telling your their HT procedure and how they test. Heck just look around here, this sub-forum is full of guys sharing their specific HT protocols. Some of them do have their own Rockwell testers. What I'm saying is, don't be afraid to ask, it's a reasonable question.
 
Hardness checks for a HTer is nothing special. If he doesn't have one go elsewhere !! You can specify HT that you want .If they can't or won't follow it go elsewhere ! There's always Peters and Bos to fall back on !
 
Even a blade that's heat treated professionally somewhere else can end up garbage if the maker doesn't keep the blade cool during finishing.
 
those are good points. While I know the HRC number is not the be all and end all, I am concerned about it because if I know what alloy it is and what hardness it is at I can sort of figure out how tough it is going to be, and I'm that guy who loves high hardness high performance materials also a curiosity thing. If I didn't know the hardness I would probably be scratching it with knives I do know the hardness of trying to figure it out.:o Do any of you find that your customers care?
 
Nebulae said:
those are good points. While I know the HRC number is not the be all and end all, I am concerned about it because if I know what alloy it is and what hardness it is at I can sort of figure out how tough it is going to be
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I wouldn't assume that. You can under-quench and under-temper a steel and arrive at the desired hrc number with high levels of RA, or other unwanted characterisitcs. Likewise it is possible to over-soak or over-quench a steel and arrive at an impressively high hrc value, then temper to the desired hardness with some pretty ugly internal structures present.
The recipe-like numbers given in data sheets do not always stack up so neatly when put into practice. Other than marketability, I could honestly care less about an hrc value once I test a knife under my own criteria. It either meets my desires or it dosen't. It is a misconception in today's knife market that the rubber meets the road on a hardness tester.
 
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Justin King said:
I wouldn't asume that. You can under-quench and under-temper a steel and arrive at the desired hrc number with high levels of RA, or other unwanted characterisitcs. Likewise it is possible to over-soak or over-quench a steel and arrive at an impressively high hrc value, then temper to the desired hardness with some pretty ugly internal structures present.
The recipe-like numbers given in data sheets do not always stack up so neatly when put into practice. Other than marketability, I could honestly care less about an hrc value once I test a knife under my own criteria. It either meets my desires or it dosen't. It is a misconception in today's knife market that the rubber meets the road on a hardness tester.
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Nicely stated Justin!

If you're concerned about a makers heat treatment, ask him his recipe. I'd assume all makers would gladly share what they do and why(our wives/girlfriends get tired of hearing it so it's nice to have someone listen..) Did he normalize, how many times, what quench did he use, triple quenched, salt pots etc.... and how long and at what temp was it tempered. Then, what does he do to test his blades. Chopping wood, or deer antler then slicing news print. Destruction testing, edge flex on a brass rod, etc etc. You'll know pretty quickly if the guy is using sound, tested methods to get the blade right.
Those things are WAY more important to know than the HRC. You'll know really quickly if he's knowledgable on the proper heat treatment w/o ever knowing the HRC.
 
Nebulae said:
Do any of you find that customers prefer knives with professional Heat treatment, or your own.
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I have a digital programmable EvenHeat, so getting a professional HT isn't terribly difficult. Most people who make a lot of knives have a similar setup.

Buyers should make a point to discuss HT methods with the maker prior to purchase. When in doubt, ask! Chances are the maker will be more than happy to give you specifics!
 
Nebulae said:
Also I will NOT buy a blade if I do not know the exact HRC number
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That's pretty much impossible, just FYI. You can test even a small 3.5" blade in three places and get HRC readings with a variance of 4. The finish of the blade, how smooth it is, if the blade is even slightly bowed, etc. can throw the tester off. Plus, a brand new, or newly factory recalibrated, Rockwell C hardness tester is only certified to be accurate to within +/- 1 point meaning it could be off by as much as 2 points.

Oh, and +1 to Nathan's comments. These were the exact reasons I decided to do my heat treat in house and spent the money on a programmable HT oven, and all the parts to go with heat treating process....tongs, LN, quench plates, etc.

At first I wanted to farm out my HT to one of the respected HT'ers. Ultimately I decided not to because they could (or would) not give me what I wanted. With small batch HT'ing, I can get exactly what I want and what is pretty well accepted as a better HT for what my knives intended use it.....a kitchen...than the big HT place could give me.
 
Aslo, I believe few if any of the professional HT'ers would do a clay backed blade. And, even if they did, that's something I'd want to do myself.

Dave
 
FWIW Peters does clay for $10, but I dont use fast quenching steels anyway. I never thought about poor results from pro HT shops due to batch concerns and corner cutting. Everybody here always says Bos and Peters do great work; I hope that is the case because I have a couple of blades on the way to Peters right now.

Also I know that Rockwell numbers are always at least +/- 1 (by exact I meant with an actual hardness tester and not the files), and not necessarily indicative of proper heat treatment, but having a RC number is just more imformation than not. Also for me, if someone has a Rockwell tester in their shop it shows a serious commitment to the science of the process I have even looked at getting one for myself, and I dont even have a kiln. That and The Rockwell number is accurate measure of hardness which correlates heavily to edge retention.
 
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Im a noob thinking about getting some knife steel on line, setting up a bevel jig and making a couple little knives (just for fun). The part im worried about is the tempering. Do you know who i could farm that out to and how much it would cost?
 
Rsq said:
Im a noob thinking about getting some knife steel on line, setting up a bevel jig and making a couple little knives (just for fun). The part im worried about is the tempering. Do you know who i could farm that out to and how much it would cost?
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If you read this post - it may help you on many subjects, but the heat treating can be sent out.

Peters is the only one that does oil hardening steel.
The other only do air hardening steels.

Texas may be the cheapest for one or two blades.

http://www.bladeforums.com/forums/showthread.php/868155-grinding-the-bevel?p=9833135#post9833135
 
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