Grain refinement and strength

[kbaknife]

Ol'Rooster - Kevin Evans - had some recent shoulder surgery guys.
Poor fella was so stove-up he couldn't make any knives or accomplish anything on his huge Missouri ranch, so he crossed the Mighty Miss' and came over to visit me for a spell.
After we got done solving the World's problems, we focused on knife making.
I've experienced a great deal of success with my "private stock" 1" square 5160 made back in '84.
So, yesterday, we got to discussing grain size and how it relates to the strength of a blade. I had a few blades on my bench that had been forged, thermal cycled and hardened "Willow Bow Style", where I spent a few days with Ed Fowler learning his process of knife making.
I must emphasize that this test knife was UN-TEMPERED!! Because of the clip, when I hardened it, the point dropped some - which I experience occasionally when I have a false edge - and I didn't like what it did to the profile, so I never bothered to temper it.
I thought maybe we ought to indulge ourselves in a little test!
I put my testing clamp where you see the break here.
Put it in my vise and had hoped that it would break rather easily since it was never tempered.
Boy, was I wrong! I couldn't even flex it.
I had to go get my 4 foot cheater pipe to even insult this little 7 inch blade.
By the time I finally got it bent far enough to break, I had made about 7-8 attempts with that 4' pipe and was well over 90 degrees.
Each time I failed, the knife went back to perfectly straight, except for the tang.
I finally got the pipe down, layed on it, and broke the knife.
You can see that the portion ahead of the break almost went back straight.
The grain is indistinguisable by the naked eye.
I had no idea that properly done 5160 in the un-tempered state could be so tough!!
This is our goal in proper heat treating, is to set up the grain size PRIOR to hardening.
This post only re-emphasizes what Lin spoke of a month or so ago when he was referring to the strength of steel with properly set-up grain size.

 

 

[DANA HOLMAN]

Nice Karl, i would of thought it would snap right in to on the first bend, not being tempered. tell kevin hope he get better
dana

[kbaknife]

Originally posted by DANA HOLMAN:
Nice Karl, i would of thought it would snap right in to on the first bend, not being tempered. tell kevin hope he get better
dana

That's the whole point, Dana -  I couldn't get it bent!!
It didn't break until I got it bent sufficiently, which took repeated attempts with a four foot cheater pipe.
I didn't bend it 90 degress over and over.
I couldn't even get it there.
The pipe kept slipping out of my hands, or I didn't have my footing right, etc. to get the thing pulled over.
There was far too much resistance from the blade.

[Bill Kissner]

If youda had a lard butt like me on that cheater, I woulda broke it the first pull!  :D  Ya just don't have enough lead in yer pants Karl!  

[kbaknife]

Originally posted by Bill Kissner:
If youda had a lard butt like me on that cheater, I woulda broke it the first pull!   :D   Ya just don't have enough lead in yer pants Karl!      

Well, Bill, you're probably right, but please don't try this with your knife.
It's too dang pretty.
You'd only end up scratching the blade!
Yours has been tempered three times and that just makes them tougher!!

[Kevin Evans]

It was great to get some help from a great guy and great knife maker.I thought I was getting along ok till I saw how it was supposed to be done,guys take it from me if you know a JS or MS that can or will help, take it.If not go to school like Tippet or Steve  did or maybe even a Hammer-in.
It was really quite funny watching Karl try to break the blade (you had to see his eyes )when he was jumping on the cheater pipe.
If you guys knew all the steps he goes through making a blade you would see why they are tough and get extremely sharp and stay sharp!!!
Thanks Karl for helping me make one of my goals this year, to make better blades,I really appreciate the help. Kevin

[Steve Nuckels]

That is too cool!  Thanks for sharing!

Kevin, I hope your making a great recovery and will be in prime condition for your ABS school.  I have been trying to hook up with a local MS!

I'm going to work on that 5160 you sent me soon my friend!

     

-----------------
IN GOD WE TRUST

[kbaknife]

Originally posted by Steve Nuckels:

I'm going to work on that 5160 you sent me soon my friend!

     

-----------------
IN GOD WE TRUST

I hope you do get to use it.
Remember that it's not the steel - it's what you do with it.