Have you read "Knife Engineering: Steel, heat treating and geometry"

[Marcus_Aurelius]

The owner of the website KnifeSteelNerds has a PhD in metallurgy and he uses the site to create and publish articles and data on all aspects of metallurgy, especially the metallurgy of knife steel (as per the name of the site ). There are around 100 articles to read and they are all really comprehensive but very detailed. They will really bring out your inner-nerd. 

Anyways, Dr. Larrin Thomas (the owner of the site) just published a book all to do with the engineering of blades. Personally, I am going to order my copy tonight, but I have heard some great things about it. Have any of y'all read it? If so, what do you think? Perhaps a mini-review is in order?

Mark

[Steve Sells]

It is a bit odd posting a book review with no review and not naming the book dont ya think?

[Marcus_Aurelius]

I can't believe I forgot to name the book, you caught me red handed this time .

The book is.... Knife Engineering: Steel, Heat Treating, and geometry, written by Dr. Larrin Thomas.

concerning the review, I'm hoping others have read the book and may give their opinion. (I believe it came out in July, so I guess that is a shot in the dark)

 

 

[Reaper.IWP]

Sounds interesting, blade smithing has always been something I’ve enjoyed. I have had the luck of working on a solid range of blade types, from a Scottish Claymore to Japanese Blades (Katana, Wakizashi, & Tanto) plus a range of knives for different uses. I still don’t honestly believe I will master any of them in my lifetime, but doesn’t mean I won’t try! 
 

I will have to check this out, maybe it will have what’s needed for me to make at least one high quality Japanese set. I have trained in kendo, and Nito ryu the dual sword technique, and would like to make my own quality set. The weapon is extension of self, forging my own would be the best way to fully bond with that extension. 
 

I am new to the community so this may be something Everyone knows, but when I was learning in Japan the technique of strengthening the blade and creating the metal color variation. The use of extremely watered down fire mortar down the spine or mune, and than kinda drawing x shapes through it towards the blade side to create the tempered line once put back in the forge. Strengthens the blade and helps maintain its edge.

Combined with setting up you cooling baths with a compass, to be lined up with magnetic north and south, Since the molecules are moving at an extremely fast speed when hot, the magnetic poles have a greater impact on them, so when they rapid cool they do so with a stronger result. Sorry, if this is nothing useful just wanted to increase site activity.

OP: thanks for the info looking into book ASAP.

[Marcus_Aurelius]

Welcome to the forums!

That is some interesting information, the process of using clay on the spine of a blade to create a hamon is a technique I have always wanted to try, it also gives me an excuse to make a chopper. As I understand the process the clay keeps the spine from fully hardening as it prevents direct contanct with the quencing medium. Then a blade is produced with a hard edge and flexible spine, cool stuff indeed.

Did you apprentice with a smith in Japan?

I have heard of lining the quench tub up from north to south, but I have always heard that it was nonsense, have you tried this method with results? An intersting idea regardless.

- Mark

[Steve Sells]

33 minutes ago, Reaper.IWP said:

Combined with setting up you cooling baths with a compass, to be lined up with magnetic north and south, Since the molecules are moving at an extremely fast speed when hot, the magnetic poles have a greater impact on them, so when they rapid cool they do so with a stronger result. Sorry, if this is nothing useful just wanted to increase site activity.

Nonsense, I don't know who told you about this but they lied.  The Earths magnetic field has nothing to do with hardening steel

[Frazer]

I have heard of pointing the horn of your anvil due north while forge welding to prevent a magnetic imbalance in the piece to be welded and causing incomplete fusion of the pieces.  Of course that was stated in a satirical sense. I've never heard of quenching in a north-south orientation.... They taught you that in Japan?

It sounds like you're describing a differential hardening, like is done when creating a hamon, only with a less defined line. The x pattern I imagine is to have a smooth transition in cooling rate from the edge to the spine. This results in a hard edge, but a softer spine thereby strengthening the blade. I'm not experienced at all with these techniques and I'm sure some of the experts in this area could describe it better, I have just never heard of quenching in a specific cardinal direction.. Seems unlikely that would make any difference, but if it is the practice I imagine there is a certain amount of tradition in it rather than it actually yielding better results.

 

PS, Marcus is a faster typist than I am

[ThomasPowers]

Please tell us more about your background and experience!    How long were you in Japan and who did you study under?Have you done any bloomery smelting---either with the Japanese Tatara or Western European or African bloomery setups? Any work with oroshigane?  What is your experience with "modern" alloys in bladesmithing  Can you tell us about the role of ashi on Japanese blades and why it's not seen in European bladesmithing?

My thoughts on some of this:   Differential hardening works best with shallow hardening steels; that also tend to have very short times to get under the nose of the curve. Most modern steels do not support differential hardening well; though a number will profit from differential tempering.

As for the N-S alignment: when at quenching temp; steel is non-magnetic.   Aligning the dipoles as the steel goes through the curie temp does not increase strength---as has been shown by laboratory testing rather than anecdotal urban legends.  It is possible to induce a low level of magnetism in the steel which tends to have negative effects like attracting dust and being harder to clean.

When dealing with traditional methods; it is always difficult to separate the wheat from the chaff---as they have grown out of what seems to work and testing which parts are necessary vs those that are just holdovers generally is not done in a controlled and well documented way.  Adding in of pseudo science reasons that then get spread like Urban Legends does not help either.  I have also read of phases of the moon affecting steel when quenched due to tides...I'm helped with my experiments in that the next building over from where I work is a Materials Science research building and I'm friends with a Metallurgist over there...Perhaps I can talk a student to do a research program on the N-S idea using Charpy testing to produce well documented results to publish. 

[George N. M.]

Extraordinary claims require extraordinary evidence.  I'm pretty skeptical of the orientation of a blade in the earth's magnetic field during forging or heat treating having any measurable effect absent any testing such as Thomas suggests.  The earth's magnetic field is pretty weak on that scale and can be distorted by things like electric currents.  What about the use of induction forges?

"By hammer and hand all arts do stand."

[Frosty]

I stack it on the same shelf with used car salesmen's claims. If magnetizing the steel improved anything a bar magnet would be easier. I have too demagnetizers in the shop because it's such a PITA keeping a magnet clean. 

Frosty The Lucky.

[Buster Bolster]

Not much on the review of this book above. I bought the book shortly after it came out, but have generally used simple steels for knives sometimes, but more often tools. Larrin's website is a better resource than the book, in my opinion, and I don't know which is better if someone wants to support him - but I would guess patreon gets more of the same dollars to him as a %. 

A lot of things in the book center around really high temp soak steels and things like carbide coarsening and if you're a reader and seldom a doer, it gives something to read end to end, but learning to heat treat is easier with back and forth reference between attempts to improve what you're actually doing in front of you in the shop. 

When it came out, and maybe it's still the case, it was inexpensive, though. It looks like it may be a few dollars more now or maybe I'm just not remembering that it was the same 3 years ago. 

The level of information in it is thorough enough that it's not summary leaving you asking a lot of questions, but it's also not like reading a research paper on steel where you're left feeling like you need some other references to decipher what's in it.