Super Steel

Rusty McDonald

Rusty McDonald

Joined
Mar 28, 2007
Messages
1,171
Ok here is the story. I went to Al's for the monthly meeting in December. The ABS school has had a class on basic bladesmithing for the past couple of weeks and some of the students and the instructor (JR Cook) atended the meeting.

At the begening of the meeting Mr Cook had a story for us all. As a usual part of the class they hammer out a knife with a blade the same size as you would make for the Journeymans test, They then heat treat, grind and sharpen the blade. After this they cut manila rope several times, chop 2x4's, and this is where it gets intresting, the edge is ground off and they bend the blade not 90 degrees but 180 degrees both directions 15 times before it cracks on the edge, and keep doing this until it breaks, some 20+ times. The blade was 5160. I'm pretty sure he said they edge quenched it, and did it in the forge not in an oven. If someone other than JR Cook had told me that, there is no way I would believe it.
 
I think that's the super secret second MS test..... I've heard similar stories but just kinda stored them in the "oh well that's neat" file.
 
Neat or not, that has to be some tough steel if you can abuse it to that degree with out it snaping like a pencil.
 
While it could be called tough as well, the more accurate term would be that is one ductile knife. Steel is amazing stuff that we often take for granted, be it in its strength or in its ductility. One thing that is of concern for the accuracy of the story, as it has been “misinterpreted” in the past, is the difference between two 90 degree bends and a 180 degree bend, this would be two 90 degree bends:

90x2.jpg


and…

180.jpg


..this would be a 180 degree bend!

I believe Mr. Cook and my other friends at Al’s are too straight of shooters to intentionally mislead folks on that point. But if the point is just a technicality, I would like to mention that 2 years ago at the Ashokan Seminar I wowed the crowd by flexing a hunting knife 360 degrees and it returned to perfectly straight afterwards!

As I mentioned in the past some folks have played some technical semantics with the math on this topic in order to make a tall tale even taller, and when I found out that one could add two 90’s together to get 180, I said “great! If it is acceptable to incorporate such fuzzy math why stop at adding just two 90 bends to get your total?” How about a 45 and a 45 for your 90? Or how about 1 degree 360 times?:D

In the end steel is amazing stuff and if you eliminate many of the points for crack propagation (like spheroidizing instead of lamellar annealing) and get way ahead of strain hardening (Well annealed mild steel would probably tire one out in bending back and forth), it can be pretty soft stuff as well as really hard stuff.

I am happy to hear that the boys did that with good old 5160, I would be even happier to hear that all they did was be really careful in a good old fashioned ABS school heat treat.:) :thumbup:
 
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They, the students and Mr Cook said they Bent it like a horseshoe. A full 180 in one bend, I remember this clearly because there were a couple of MS there that made it a point to ask that question.
 
Excellent!:thumbup: I will have to congratulate J.R on doing it to the letter the next time I see him. I especially like how it makes the extraordinary seem a little more ordinary (and achievable):D. Those other masters who pointed that out were thinking just what I would have been thinking;)
 
I didn't post this to get any one in trouble, that was never my intention. But I do agree that saftey is paramount in and around the classroom or shop.
 
No worries, you are fine, I doubt there are any safety issues involved at all. I am sure we will have the same grin on our faces if we discuss it.
 
I for one would be more comfortable discussing this with a nice beer and a steak in front of me...... but that's just me. :D
 
Here are a couple of picture of Kevin conducting that spectacular 360 degree flex. Note that he had to have two burly helpers hold the table down for him, and that the blade sprang back true at the end.

Kevin-conducting-360-degree-flex-te.jpg


Kevin-triumphant.jpg
 
kevin....that bend is very impressive u did.....even more impressive it came back to true....quick question for ya if u don't mind.....i know u say flexibility has to do with thickness.....like a fillet knife.....it's ground very very thin so it has flex.....is a 360 degree bend esier with a knife that is longer?.....hope that's not too stupid a question....it seems to follow the same logic to me....ryan
 
ryan9977 said:
kevin....that bend is very impressive u did.....even more impressive it came back to true....quick question for ya if u don't mind.....i know u say flexibility has to do with thickness.....like a fillet knife.....it's ground very very thin so it has flex.....is a 360 degree bend esier with a knife that is longer?.....hope that's not too stupid a question....it seems to follow the same logic to me....ryan
Click to expand...


If you were to take a spring tempered "knife" that was only .020" thick and was six feet long, you could wind it around a dozen times. Then you'd have a clock spring...
 
First things first. Henceforth, it is no longer acceptable to take any photos of Mr. Cashen from any angle except the front and below the 4 foot level so as to be shooting up to Mr. Cashen. If Mr. Cashen is bending or in any position except completely upright only facial closeups will be allowed. Before signing the standard models photo release Mr. Cashen will have to review each photo to be certain that inappropriate exposure of empty follicular dermis is not evident. This is for his benefit as well as for the safety of your photography equipment as certain angles will give an amplified light feedback which could blind the audience or damage the camera, this problem is expected to grow with time:(.

In the simplest terms, with each passing year it would be less embarrassing (and less bare skin) to have photos of my bare ass than to see the glare coming off the top of my head:( You see I cannot generally see it myself when facing the mirror. ;)
 
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