Annealing problem

K

KodyL

Joined
Jul 14, 2016
Messages
47
HI Gent's. New to the forum and knife making and need some advice. In the process of making a letter opening dagger from a unidentified file steel made in Japan that belonged to my Sister's late husband. While taking a break I decided I needed/wanted a scribe for making the center line. I got the bright idea of making a small shop knife. I had a few old Dewalt Sawzall blades laying around and started a new project. Got to the point of putting a handle on it and needed to drill holes in it for a couple of pins. I placed the blade in a vise with a wet rag on top and heated the tang with a map gas torch to cherry red, checked with a magnet and let it cool. Next day went to drill holes and the drill bit wouldn't touch it ,,,, figured maybe not long enough soak, Re did it and the same thing. What did I miss ??? Also what hardening process would you suggest for a unidentifiable steel. I was planning to treat it like 1095
 
A couple of weeks ago I was working on a few blanks out of 1095, and I forgot to resize the holes. They weren't quenched yet, but I have gone through 3 grain refinement cycles, with air cooling to black. I was unable to resize the holes with a hss bit. It was not hard as quenched, but hard enough to dull the bit before I finished the second hole. I wasn't expecting that from a shallow hardening steel like 1095... I can only expect oil hardening or air hardening steels to be much worse.
 
I cant tell you what you did wrong because I'm new to heat treating. I know that annealing should be done by cooling down the steel very slowly. Did you try to put the blade into an something like ash or vermiculite? I have heard that these work well for insulating the hot steel. It allows it to cool down very slowly. It may be possible that the steel air hardened because it didn't cool at a slower rate? I don't know. I cant wait to hear the replies you get. I'm interested in learning about it myself.
 
Well, who knows what the steel in that blade was... at any rate, you either failed to remove its hardness (if a high-speed steel) or basically re-hardened in air (carbon steels.) If it's a high speed steel, and you must finish the thing, I'd say just epoxy a handle on and see how long it lasts. I would in no way recommend making knives from old Sawzall blades, but if it's just for your own use in the shop I guess tinker with it and see if you can make it work.

If it's a lower alloy high carbon steel, you could find out maybe- try heating it to a dull red (still magnetic) and air cooling to black, then quench in oil. Repeat twice more. This often works a lot better than trying to anneal by slow cooling, with steels in the 1% or greater carbon content range.
 
Like Salem says - who knows what the blade was.

The steel is probably M4 or a similar HSS. It will harden if heated and slow cooled. Annealing tool steel requires an oven and a careful and long procedure.
 
Last edited:
I would try to treat it as if I was welding and annealing a bandsaw blade. Heat it to orange, allow to cool past dull red, heat it just past dull red, let it cool in air to a lesser shade, then put the heat back to it, then let it cool, keep bringing it up to a lower temp and allowing it to cool to a lower temp each time.

When doing it on a band welder it's easy because you can just cycle the button, a little tougher with a torch, but the point being allowing it to cool too quickly prevents the annealing action you're looking for.
 
Thanks for all the replies. I'll just epoxy it together. It' just a scribe tool/box cutter type thing ,,,, lol. For my mystery steel file letter opener dagger I think I'll just treat it like 1095 and see what happens. Thanks again.
 
Sawzall blades are high speed steel. The annealing process goes something like this. put in oven and raise temp to 2300 deg. soak for 1 hour. gradually reduce temp 3 degrees per hour over the next several days until you reach the target temp of 1800 degrees. As you can see this is simply not practical for most of us.

Personally I like to use salvaged HSS. I find it holds an edge much longer than any normal high carbon steel I have tried. You must realize that it cannot be forged. It will either splatter or shatter. Neither can you effect the temper. The only way to work it, is cut and grind, and the only way I've found to put a handle on it is epoxy.
 
Last edited:
10hammers said:
Sawzall blades are high speed steel. The annealing process goes something like this. put in oven and raise temp to 2300 deg. soak for 1 hour. gradually reduce temp 3 degrees per hour over the next several days until you reach the target temp of 1800 degrees. As you can see this is simply not practical for most of us.

Personally I like to use salvaged HSS. I find it holds an edge much longer than any normal high carbon steel I have tried. You must realize that it cannot be forged. It will either splatter or shatter. Neither can you effect the temper. The only way to work it, is cut and grind, and the only way I've found to put a handle on it is epoxy.
Click to expand...

That's good info, thanks. I only knew that reciprocating saw blades were usually bimetal, but I didn't know exactly what it was. I also had no idea about how to HT HSS. Thanks for the heads up, now I know.
 
10hammers said:
Sawzall blades are high speed steel. The annealing process goes something like this. put in oven and raise temp to 2300 deg. soak for 1 hour. gradually reduce temp 3 degrees per hour over the next several days until you reach the target temp of 1800 degrees. As you can see this is simply not practical for most of us.

Personally I like to use salvaged HSS. I find it holds an edge much longer than any normal high carbon steel I have tried. You must realize that it cannot be forged. It will either splatter or shatter. Neither can you effect the temper. The only way to work it, is cut and grind, and the only way I've found to put a handle on it is epoxy.
Click to expand...

I'm sorry, but this is not accurate information. Yes, you need to heat then cool slowly to anneal, but no grade of HSS is 3 degrees per hour. Most are between 20 and 50 degrees per hour. It certainly can be forged, at least the m-types can, and various suppliers like Crucible will give forging temperatures for their particular alloy. It will not "splatter or shatter" though it is incredibly hard to work with a hammer and more susceptible to cracking if forged at too low of a temperature.

"Neither can you effect the temper." What? Then how is it possible you can anneal it? Why do drill bits or lathe tools left a moment too long on the grinder, turn straw to blue color? Because your are affecting the temper, and effect the was that you lost it by over heating.
 
You must log in or register to reply here.
Back
Top