How to evaluate heat treat from small knife maker?

[candlelight001]

I've been considering buying a handmade knife from a few of the different makers on this forum, or indirectly through the exchange. I've read that "it's all in the heat treat!" How do I evaluate if a smaller knifemaker does a good heat treat? I realize reputation may be a part of it, but I'd rather not get specific about particular makers in this thread. More just how do I know if something's good? Thanks!

 

[CWL]

I think that reputation means everything when it comes to custom knifemakers. (Even if something goes wrong with a knife, the well-known ones selling on this forum all stand behind their products.)

Beyond that, it really comes down to how well you can use knives to evaluate their performance.

 

[richard j]

just ask anyone that has a knife made by the maker you are interested in what they think about the knife and how it has held up. thats the easiest way to find out about a makers work.

 

[george tichbourne]

Ask the maker how the knife was heat treated. There should no hesitation to give the information.

Heat treating with a propane torch is an indication that the maker is not serious about the quality of heat treat.

Sending a knife out to a professional heat treater is also a good sign, nothing like having it done by someone who does nothing but heat treating 24-7.

George

 

[teacher]

Go here ....... Shop Talk - BladeSmith Questions and Answers ...... and Around the Grinder... ask this question and I'll bet you'll get some good practical answers. :thumbup:

I know a "little bit" about it....... just enough to get you confused...........

These guys will most likely give you some good advice.

 

[Gossman Knives]

Using the proper HTing equipment and data for the given steel type.
Scott

 

[george tichbourne]

Just to clarify, use of a plumbing propane torch to heat treat is not all bad but only if the torch can supply enough heat to reach the critical temperature for the steel being treated.........Insufficient heat results in incomplete hardening.

Some of the people working with simpler steels like O1, and the 10XX series steel do heat treat with a torch, (usually an oxy/acetylene torch) in order to achieve high enough temperatures.

People using air hardening stainless steels cannot get away with this process however. The heat treating formula is just too complex to achieve proper results using the torch method.

George

 

[richard j]

thanks george for posting that information. i heat treat with a oxy/acetylene torch and have done so for enough years that i get consistent results and i'm usually within a point or two of the rockwell hardness that i'm wanting. it took me a lot of experimenting with different quench oils before i made my first knife to get the results i wanted.

 

[Nathan the Machinist]

It isn't just hitting an austenitizing temperature, it is also holding that temperature long enough to free up the correct amount of carbon and allow it to diffuse into what will become the martensite. O1 needs a good soak (ideally over ten minutes), D2 needs a soak at over 1800 deg for over half an hour!

One way to evaluate the HT is to take a similar knife of a known good HT and your new knife and subject them to the same tests. Assuming they are similar geometry and sharpened the same, when subjected to the same amount of cuts in the same cardboard, then the same amount of cuts in the same leather, then perhaps hardwood or whatever kinds of use that would be appropriate for the type of knife, you will see which one goes dull faster and by what mechanism.

Now obviously, even a well heat treated 1084 kitchen knife isn't going to hold up as well as a so so S30V blade in something abrasive, nor is a good S30V blade going to maintain as fine an edge popping into a cutting board as even a so so 1084 blade. You have to compare apples to apples.