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Steel Performance, Heat Treat Or Geometry.

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Posts: 64
Trusted Member Apprentice Bladesmith
Topic starter
 

Afternoon folks,

My request today falls I think under parlor trick categories in that there is hardly ever a reason I coukd see needing to perform this task with a blade, but never the less I keep getting people asking me if I can make them a blade that would do it. That task is of course cutting other steel. Whether it be being hammered through chains or all thread rod or wire rope and coming out the other side completely unscathed, I haven't been able to do it. I figured it might have to be done with a thick full convex grind or something like that but then I see Bob kramer perform the bolt chop with a thin chefs knife so....is it all in heat treat? Should all 52100 and 1095 and 5160 be able to go through steel? What is the target Rockwell for something like this? Too hard I chip, too soft I deform to the shape I'm trying to go through. It's got to be a matter of one point Rockwell up or down from bang on I wager. Any input or solid theory or past experiences would be well appreciated thanks guys.

 
Posted : 15/10/2016 3:01 pm
Posts: 775
Noble Member Apprentice Bladesmith
 

Jesse,

My best tip for you would be to stick with one particular steel (your favorite) and don't use anything else until you are confident that you can make it do what you want it to every time. If you start jumping from one steel to another then it may get unclear why you don't achieve what you want. If you don't have a favorite steel then I'd suggest either 1084 or 5160. Both will make an excellent blade and are very forgiving steels re: H/T.

Gary

 
Posted : 15/10/2016 5:19 pm
Posts: 71
Member
 

Hi

Most of what you're concerned about might be the bolt itself...not your knife steel or heat treating

There are bolts made that you can't chisel apart at all...there are others that you can chew, drill and chisel....they are made on the soft side for a purpose

Ernie

Ernie Grospitch

 
Posted : 15/10/2016 8:13 pm
Karl B. Andersen
Posts: 1067
Member
 

Geometry cuts.

Heat treatment determines how long.

And soft bolts help.

You can cut yourself with a piece of paper or maybe a sharp edge on a piece of wood. But neither are hard.

That's the geometry cutting.

A hardened and properly tempered piece of tool steel should be able to cut a softer bolt. It only stands to reason.

Different alloys make them tough, like nickel.

Not only one steel will do it, and not only one geometry or hardness.

You just need to find the right recipe for your chosen steel type.

I think you'll do it.

(Take pictures)

Karl B. Andersen

Journeyman Smith

 
Posted : 15/10/2016 8:55 pm
Posts: 64
Trusted Member Apprentice Bladesmith
Topic starter
 

Thanks guys,

I use 5160 and w1 mostly when I want a nice Hamon. And a 1080/15n20 mix for my Damascus.

I guess all that's left to do is get out to the shop and find the recipe that works, snap some shots and video of my success and get back on with my life! Lol.

Thanks again.

 
Posted : 16/10/2016 5:20 pm
Posts: 0
New Member Guest
 

I was at JD Smith's home and we were playing around. He was teaching me and another new guy at the time. JD made a knife, a small fighter type, out of a blank of steel he had laying around. It would have either been 1084 or 1095 because he was using those to make pattern welded stock. He heat treated it with a torch. After tempering by eye, he suddenly and without warning turned and drove the knife through a piece of sheet steel on an old tool box, just about as hard as he could thrust it. JD likes a little flourish and fun sometimes. We jumped back. He wrenched the knife out, and without looking at it, held it up to us and said, "How does the tip look? Not a scratch, not a bend, right?"

He evidently does this sort of thing in front of classes fairly regularly. I love that man.

Anyway, the point is that hard steel (think cold chisel or engraver) cuts soft steel pretty much every time. Heat treatment is the key to surviving it, and it will be a combination thing (the thicker the edge, the softer I would guess). but there will be the two extremes, thin and brittle, thick but mushy. In between there will be a whole interaction of geometry and hardness that will work.

I have cut mild steel rods often as demonstrations myself after seeing JD's trick, and I personally use w2 and 80CrV2.

Or 1075 or 15n20 but they would be second choices. The reason is because those are the steels I have spent the most time heat treating, and I know that my recipe works with my setup for those steels. I rarely deviate from the small set of things I know the best. The advice you got from Karl, Gary, and Ernie is golden. I just thought you might like to know the JD story.

 
Posted : 08/12/2016 5:24 am
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