I am definitely not experienced enough to give a solid answer myself but I was able to find a youtube video that I watched a year or so ago where Master Smith Jim Crowell talks about this (starting at 1:18). https://www.youtube.com/watch?v=y_UWEIuRVmQ

To sum up what he says edge quenching is bad but edge hardening is good. The difference being edge quenching you heat the whole blade but only quench the edge, versus edge hardening you only heat the edge.

- Andrew

Thanks for the reply Andrew, I’m going to check out the video.

|quoted:

Hello,

I am wondering, does the ABS still recommend edge quenching. The introduction to blade smithing booklet still shows this. I’m asking because someone on Facebook (I know) was saying that it is an old and outdated practice and causes stress at the quench line. What does the ABS say about this as I would think there are many master smiths who have passes there tests with edge quenched blades?

Marc

Hello Marc,

The ABS, as a whole, really doesn't say much on the topic except as a method to pass the bend test. While it is still in the "Intro to Bladesmithing" book, and some instructors may use that section of the book, I no longer teach edge quenching in my Intro classes.

For a long time I advised not to use the edge quenching method on blades that you were going to sell or anywhere the heat treatment really counted, but considered it a necessary evil in making a test blade. But after examining the safety issues as well as the results, I can no longer justify teaching it at all.

With the greater presence of decent quenching oils edge quenching not only presents a safety concern, it also is very detrimental to the oil. The thermal dynamics of using a static 1/2" of oil, with an entire hot blade above it, working against the process, results in lackluster results. My personal observances has shown mixed microstructures that make a blade easy to bend but not optimum for edge stability. With the popularity of simple alloyed steels, such as 5160 or 80CrV2, the mixed microstructure issues will also be present in the spine of the edge quenched blade as well.

What I now teach is differential hardening via the popular clay method. This actually results in even better control for the bend test while providing significantly less compromise of the cutting edge heat treatment. Since the clayed blade is fully quenched, the chances of flashing the oil are greatly reduced. With the ubiquitous popularity of hamons at this time in the knife business it seems like a no brainer.

Keven,

Thanks for the info. This is why I joined ABS, because having someone like you reply to my question is a honor. I am using the clay method mostly for the hamon, but I was wondering if I would need to do an edge quench when I’m ready to test for journeyman. I still have one more year to wait, and hopefully I will be ready by then. I still have so much to learn.

I really need to go do one of the intro classes so I don’t develop bad habits that will be harder to break later on. This COVID thing is messing up my plans.

Are there still live in person classes being offered now, if so I really need to make time for one.

Anyways your work is mind blowing, much respect man, and thanks again for chiming in.

Marc

|quoted:

Keven,

Thanks for the info. This is why I joined ABS, because having someone like you reply to my question is a honor. I am using the clay method mostly for the hamon, but I was wondering if I would need to do an edge quench when I’m ready to test for journeyman. I still have one more year to wait, and hopefully I will be ready by then. I still have so much to learn.

I really need to go do one of the intro classes so I don’t develop bad habits that will be harder to break later on. This COVID thing is messing up my plans.

Are there still live in person classes being offered now, if so I really need to make time for one.

Anyways your work is mind blowing, much respect man, and thanks again for chiming in.

Marc

You are welcome. Let me know if I can help in any other way. There are classes still being held. What you need to do is check each of the facilities that offer ABS classes. The ABS only provides the instructor and the curriculum, the facility that hosts the school does everything else and is in control of whether the classes go on or not. Heck, I have had people say that the one year Journeyman exemption for taking a class was a way for the ABS to sell classes, when I begin laughing I then have to explain that the ABS doesn't get dime from it, class fees go to the facility to cover costs.