JS test knife question

jdm61

jdm61

itinerant metal pounder
Joined
Aug 12, 2005
Messages
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I had finished up forging a hunter and hamering abit on my latest attempt to make a Moran ST23 stylknife andI got to thinking about the JS test knife. I happened tohave some old 5160 leaf spring lyingaound so I have the beginnings of a 9 1/2 x 1 3/4 spear point test style blade. My qustion is this. Does clay hardening a blade leave the spine and tang too hard to pass the bend test? This will dtermine what stell I actually test with. The W2 that Ihave been using gets VERY soft when properly annealed, but I wouldn't want to try to edge quench it. If I have to edge quench, I would be inclined to try 1075 first and if that didn' work, then the thick 5160 that I got from Uncle Al.
 
Joe, it's hard to go wrong with 5160 on that knife. I used 52100 and was elated with the results.

I fully hardened mine and used "tempering tongs" that you heat up in the forge and then clamp onto the spine while the cutting edge is in a trough of water.

Similar to a torch, but a little more control/predictability.

My cutting edge should have been 61 Rc because that's where I left the blade after tempering (Rockwell tested the ricasso since it was flat). It's hard to get an accurate Rc on an angled piece, but it tested around 48 on the spine.

Clay hardened W2 will definitely pass the test as well, but I'd shoot for about about 1/2 of the blade width to be hard.

I think it's a lot more impressive when you see a knife with a nice arc in it after the bend test than one that looks like it was made for cutting perfect 90degree angles :)
 
Joe, W2 makes a very good cutting blade. 5160 makes a very good bending blade;) Trick is to forge/grind the blade very thin and make it wider where it is going to be clamped into the vise. Thin is springy, this is what you want.
 
I know that in a fully annealed state, I can bend this W2 180 degrees without a problem. What I found out the other day messing with a failed hunter is that even in a once normalized state with no annealing, an unhardened blade about 1/8 thick or so will bend 90 and you have to twist it back and forth a few times to get it to break off. I also know that in a fully hardened state, you can't drill the stuff with a jackhammer even after extra torch tempering:D
 
Joe, W2 is not so easy to tie into a knot when harden, save it for super cutters and use to other for bending. Most of the test knives that fail, do so in the 90 deg. flex.
 
Don Hanson III said:
Joe, W2 is not so easy to tie into a knot when harden, save it for super cutters and use to other for bending. Most of the test knives that fail, do so in the 90 deg. flex.
Click to expand...
Too bad. I don't think it is humanly possible to roll the edge chopping lumber with a properly tempered W2 knife. The couple of big blades that I have done just chip out ever so slightly until you get the temper right and then you can whack on harder wood than cheap pine 2 x 4's and it won't even scratch the blade. I have chopped maple and dry 50 yr old pine 2 x 4's (real ones that are old enough to be almost a true 2 x 4 and not a 1 1/2 x 3 1/2) with no ill effect.:D I think that I may try the 1075 first because chromium and i have had trouble getting along in the past......lol.
 
W2 HTed right will pass the flex test. Just easier with a lower carbon spring steel.

Make some test blades and start testing :)
 
Joe, I forgot to mention, one of the very first knives I forged, I took to a hammer-in and tested to destruction.

It cut through two pieces of firewood (about 12" diam) and still shaved, then bent 90, back to straight, 90 the other way, back to straight, and down to about 110 the first direction before it broke.

All I really knew then was to heat it up, beat on it with the hammer, then stick it in warm oil.

That one was 5160 :D ;)

BTW- for those thick headed types, I'm not bragging, I'm pointing out that 5160 is hard to fail this test with.
 
Just a few things that caught my eye from this thread. First, it is a "bend" test, if you go to 90 degrees and it returns entirely straight that would be a "flex" test and you would definitely deserve a stamp for that accomplishment. I hate to be a broken record on this but using certain terminology only perpetuates the jargon that ammounts to so much marketing hype. The ABS is entirely straighforward about this and calls it the "bend" test in their description at http://www.americanbladesmith.com/ABS_JSTest.htm. Next, Joe you have always been a straight shooter so I am curious to know of the W2 bent to 90 twice or did it actually go to 180? This is another bit of jargon that can dance in the gray area with many

This is two 90 degree bends:
90x2.jpg


This is 180 degrees:
180.jpg


This is not my usual heavy metallurgical stuff, this is very simple geometry. To say otherwise is... well, lets move onto a better subject...

The ABS wants a bent blade, they don't specify any level of springiness or go any deeper than to say a 90 degree bend. Give them what they want. You are on the right track with the clay idea since it is a fantastic way to get full hardness on the edge and a dead soft and bendable spine, with the added benefit of being able to see exactly where the hardening stops. I would go with a shallow hardening steel of .75% carbon or less and clay it up and pass the test with flying colors. It really doesn't take much hardness or abrasion resistance to cut a rope and go through a 2x4 twice so don't get hung up on that part in your steel selection, but focus on your bend (of course do the exact opposite with your actual using blades). I hope this helps, and good luck.:thumbup:

P.S. I have some other tips if you would like to e-mail me or call, we could discuss them, in any spare time I have before the Blade show.;)
 
Kevin R. Cashen said:
Just a few things that caught my eye from this thread. First, it is a "bend" test, if you go to 90 degrees and it returns entirely straight that would be a "flex" test and you would definitely deserve a stamp for that accomplishment. I hate to be a broken record on this but using certain terminology only perpetuates the jargon that ammounts to so much marketing hype. The ABS is entirely straighforward about this and calls it the "bend" test in their description at http://www.americanbladesmith.com/ABS_JSTest.htm. Next, Joe you have always been a straight shooter so I am curious to know of the W2 bent to 90 twice or did it actually go to 180? This is another bit of jargon that can dance in the gray area with many

This is two 90 degree bends:
90x2.jpg


This is 180 degrees:
180.jpg


This is not my usual heavy metallurgical stuff, this is very simple geometry. To say otherwise is... well, lets move onto a better subject...

The ABS wants a bent blade, they don't specify any level of springiness or go any deeper than to say a 90 degree bend. Give them what they want. You are on the right track with the clay idea since it is a fantastic way to get full hardness on the edge and a dead soft and bendable spine, with the added benefit of being able to see exactly where the hardening stops. I would go with a shallow hardening steel of .75% carbon or less and clay it up and pass the test with flying colors. It really doesn't take much hardness or abrasion resistance to cut a rope and go through a 2x4 twice so don't get hung up on that part in your steel selection, but focus on your bend (of course do the exact opposite with your actual using blades). I hope this helps, and good luck.:thumbup:

P.S. I have some other tips if you would like to e-mail me or call, we could discuss them, in any spare time I have before the Blade show.;)
Click to expand...
hey Kevin,
Here is what has become my favorite paperweight. This is one of the first blades that I attemted with W2. I was about 6 inches long and by the time i gave up on trying to fix the plunge cuts it was around 1/8 thick. I figured I would snap off the tip and see what the grain looked like.......unfortunately, when I annealed it I REALLY annealed it:D So i decided to play with it. Allof these bends were done by hand with the blade in a vice. Actually, the big bend is, for lack of a better term, a "compound" bend of about 160 degrees.
 
Sorry for the flex/bend mix up Kevin. You're right, this is a "bend" test.

I've been into blades that flex instead of bending lately and got carried away.

Joe, make it cut good but bend easy :)
 
I was very confident that you knew the difference Don, I am just very surprised at the number of people who don't and can fall for that shell game with words, that is why I am such a pain about drilling the point.
 
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