All right guys, I have a couple of knives from a maker local to here that uses sawmill blades. Now, his designs aren't the best, and the quality isn't the highest (of the craftsmanship). but the blades seem to be great. I haven't used them enough to know how well they hold an edge, but they take one VERY well. I do have a cleaver also made by this guy and it works great and I haven't had a problem with the edge (discoloration can be a problem due to the high carbon I guess, definitely isn't stainless!)

Anyways, to come to the point. i was talking to somebody working the table and asked about how they heat treat the steel, temper it? (there is a local knife maker who takes it and puts it in a furnace thing he bought just for knives, then sends it to a company that does a super cold treatment of some sort on it). but this guy said that the maker doesn't temper them, that since they are starting with it pre-tempered and aren't getting it real hot they don't need to. Do you think this is true? They aren't really taking that much metal away after cutting to basic shape, as there is no sharp angle into the edge like a typical knife, it is gradual from the spine of the blade. does that make sense? (I think i will end up having to post a picture).

I am just wondering because my uncle and I were talking about trying to make a couple of knives (he is a knife addict) and by taking the need for tempering out of it the whole things is much less intimidating.

Thanks guys,

Red

For steel that is already hardened reshaping it won't affect the hardness unless you get it hot when grinding.

For your own knifemaking hardening the blade isn't that big a deal so long as you stick to carbon steel...not stainless. After you've done shaping the blade all you need to do is heat it to red heat then drop it into oil or water depending on the steel. That will harden it. Then if you are going to use the knife for something that will stress the blade temper it. First you clean it back to steel then heat until you get color change then back into the oil or water. Straw color for a light temper thru purple for heavy. The trick with this is heat the main body of the blade & watch for the color change spreading out to the edge. Then when you see the color you want on the edge quench. Tempering is trading edge holding hardness for toughness. If you screw up the tempering just reharden & retemper until you get it right. It's not something where you have to make a new blade if you screw up.

Personally if the knife is only for cutting I'll leave it glass hard & not bother with tempering.

What Turtle71 says is more or less true as long as you are not trying to get the best performance on a routine basis. If you are, things get much more complicated.


If the material is old band saw, it is probably L6. If new bandsaw it is probably 15N20. If old circular saw, again probably L6. If new circular saw with carbide inserts ... it could be a lot of things (that is, it is not predictable).

Get some O1 from MSC if you want to be certain what you are starting with. It is the right thing to do.

A reminder ... good old Johnson's Floor Wax is about the best easily obtainable rust preventative you can use on carbon steel blades. Is hard to do better.

Bandsaw might be differentially heat treated or bi-metal.

Differential the back of blade will be softer than the teeth. You might have to reharden this.

Bi-metal is high speed steel teeth welded onto a lower grade steel backing. This probably wouldn't hold an edge no matter what.

This reminds me of making "Rambo" knives as a kid out of power hacksaw blades :-)

I saw one of the blades, they are big circular saw mill blade of about 2.5 feet in diameter, maybe even bigger. they brought it in on a dolly.

I won't get to do any playing with this for a while, my uncle is getting ready to leave in about 3 weeks for asia and won't be back for who knows how long. :-( But I might by some small stock from MSC as suggested and use my small grinder at home to try to make a small folding knife.

I have this knife, you probably have all seen them, called Executive Edge here in the states. But mine is straight from Brazil, my dad brought a whole bunch back in the mid 80's before they caught on here. Very simple design, but great for the shirt pocket. I want to get one done up in Damascus or Dendretic steel. If anybody doesn't know what it looks like I can get a picture off the net and put it here. they are rather hard to find now, only one company I know of in the US selling them.

Red