"Saw blade" stock removal- hard as a rock!

[jonwelder]

I finally traded some saw blades around, (got rid of the carbid tipped blade) and got a "large" saw mill blade, about 1/4" thick. I torch-cut out a nice "bowie" style blank and ground it to shape. (I got this idea from David Boye) I did my blade profile ect. and noticed it is hard as a rock and is eating up my belts far faster than any knives I have forged out. My question: should I have heated it to orange, then let it cool slow to "soften" it first, then begin to grind and profile? Would this have made it easier to work, or would I loose any "qualitys" that this steel has by doing that,, as I suppose this steel is L-6? Also, can anyone explain what "red harden" means in reguard to L-6 steel? I liked the idea of the saw blade as it was almost free! ---jon

[sdcb27]

The steel could be anything L-6,15n20,10xx, my question is what belt and grit are you using and if its heat treated already why not just totally stock remove it and not worry about HT as your HT for it is gunna be guess and go, as for annealing it or any steel DO NOT GO BY COLORS use a magnet.

[Quenchcrack]

Jon, yeah those blades are made for abrasion resistance and do not grind easily. Annealing would help but if it happens to be an air hardening steel, you are going to have problems cooling it slow enough to soften it. If you have a bucket of vermiculite, try burying some thick chunks of red hot steel in the bucket just before you put the blade in. The extra heat will slow down the cooling rate. The term "red hardNESS" refers to the ability of the steel to experience heat up to the point where it turns red without losing its hardness. This is usually accomplished by adding up to 5% Molybdenum to the steel, which inhibits the tempering reaction. Tools that experience heat when in use (saw blades, forging dies, etc) commonly use this type of tool steel. H13 is a common hot die steel.

[Ray Rogers]

"I liked the idea of the saw blade as it was almost free!"

Not really. There are some good reasons for recycling scrap steel into useful products but financial economy usually isn't one of them. This steel was not 'free'. First you paid a little bit for it. Then you used a torch to cut it (gas consumption). The you used far too many belts trying to grind it. If you had annealed it and then re-hardened it after grinding then you would have used more gas or electricity, more belts for cleanup, and more time. Your time is valuable too, even if you don't put a value on it, you definitely have a limited supply of it so don't waste it.

When you are finished you will probably have a good blade but you won't be able to tell a buyer with certainty what steel was used. It's not important that you may plan to keep this knife for yourself - sooner or later the issue will come up. For $15 or less (including shipping) you could have bought a clean, flat, annealed piece of known tool steel for which the proper heat treat process would not be a guessing game. The only gas needed would be for the heat treat and you would not need so many belts. The knife would have come out just as good and you could tell anyone who cared what steel was used.

So, if you're going Neo-Tribal or recycling to save the planet then more power to you. But, if you are just trying to save a buck then there are probably better ways to do it. Something to think about .......

[Markus40]

I've made most of my knives over the past 15 years from sawblade steel. Some from old farrier's rasps. But I think you definitely need to anneal the steel before grinding. I use a metal cutting disc on either my 4" angle grinder or my hand saw. You go through discs pretty quickly, but it's cheaper than cutting torch gas, and you lose less material. You also don't have to deal with those horrible slag edges after torch cutting. After you cut strips out of the sawblades, heat them up to a nice cherry red (about 1600 F) and cool slowly. I just leave mine in the insulated electric oven overnight. I've never tried the vermiculite method, but I keep wanting to give it a try. Sometimes I'll get steel that doesn't anneal enough to drill, so I'm obviously not cooling it slow enough. But like everybody says, don't waste good belts on hardened steel! Get it soft, then do your grinding and drilling and put the hard back in with proper heat treating. Wayne Goddard has lots of good advice on working with sawblade steel in his book The Wonder of Knifemaking. Also David Boye's knifemaking book. I learned from both of those. I agree with what's been said about buying known steel, but some of us have a stubborn junkyard gene that gives us a jolt when we can make something useful out of recycled materials. Most of the big circular saws like lumber mill blades are L6. Concrete cutting diamond blades (which I have HUGE supply of) are typically 4140. It's only good for thick Bowie style knives because of the low carbon content. L6 makes great kitchen knives. Have fun!