Hardness vs performance

[Mark Reich]

Very interesting.  I've not heard of that before.

That's mighty surprising. Especially since you've been on Mr. Ed Fowler's Forum for years, and he's pretty famous or infamous for it.

I would have thought you'd have all kinds of opinions on the subject. 

I edge harden, then etch heavily, to bring out the hardening line, which is organically beautiful, and something very Very rarely seen. 

Everyone who looks at my blades notices it immediately. The most erroneous statement I field is, "I love your damascus!".

[Rupert Lucius]

https://www.youtube.com/watch?v=Q-ooSWhFszc

Pardon my complete ignorance, but where can I see Mark Reich's videos?

[Rupert Lucius]

https://www.youtube.com/watch?v=Q-ooSWhFszc

Pardon my complete ignorance, but where can I see Mark Reich's videos?

https://www.youtube.com/watch?v=aWENpliHWLg

[grepper]

https://www.youtube.com/channel/UC5jpBWr...hbL8zejRBw

[me2]

The torch hardening part I'm familiar with. It's the hardening the whole blade afterward that I don't think I've read before.

[Mark Reich]

Pardon my complete ignorance, but where can I see Mark Reich's videos?

Although my website is a work in progress, you can find all my videos at ReichPrecision.com

Thank you for your interest.

[Mark Reich]

The torch hardening part I'm familiar with.  It's the hardening the whole blade afterward that I don't think I've read before.

Sorry Mr. Me2, I've been meaning to answer this. I apologize for misinterpreting your query.

I use an O/A torch to heat the edge, then quench the whole blade. I look for the scale to have popped off the edge, so I know the edge was hardened. It comes out of the quench oil looking like this; 



The blade is cleaned up with grease-less abrasive on a buffer, and a light etch shows exactly how much of the blade was hardened.



With 52100, the steel that wasn't hot enough to harden is soft, which allows the etchant to have maximum effect. Different blade preparations for etching create different results, and of course, more etching magnifies the result. This blade is fully etched, but the spine is still soft.


Looks are very important to me. I want to make something that people haven't seen before. At first glance anyone can see this isn't an ordinary blade. 

The only thing more important is performance, so of course the major goal is full hardening of the entire blade. I certainly take that as seriously as anything. Getting very fine grain to HRC 65-66 takes a precise temperature, held for a certain amount of time. It requires the highest performance quench oil at the correct temperature to create the hardest martensite. Immediately after quench, it takes a steady reduction of temperature to the fullest extent to create the purest martensite with the least RA. You have to go straight from quench to cryo in LN. No, there is no time for tempering after quenching if that is the goal, so you better figure out why blades break, and eliminate the cause for that completely. Fortunately, that's not nearly as difficult as people think.   


The blades can keep their original etched patterning after full hardening, if you figure absolutely everything into the plan, so they come out looking like anything from this;





...to this;




...to this;


The only thing left is making them impossible to break. It took quite a while to figure out how to do that perfectly every time, but I can tell you it is certainly possible with very close to 100% success. Precisely drawing the spine is the last hurdle for ultimate performance.

[me2]

That's very interesting.  I've never seen anyone do it that way.  When you were working out your process, did you try going the opposite way?  Fully harden the blade first, temper to 650 to 750 F, then torch harden the edge?  I know a couple makers that take pre-hardened fully hardened blades at about 49 to 51 HRc and torch harden the edge.

[EOU]

Beautiful Mark! We're certainly not going to attempt to weigh in on the conversation (that would be like native eskimos speaking to the various attributes of window air conditioners) but we will compliment and thank you for one very most excellent post!

[Jan]

Congratulations Mr. Mark, you are producing really beautiful knives. I feel that your knife has a soul.

Jan