Blood Groove

Your preference for heat treating 1095 knives

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I'm making a roughly 12 inch knife out of 1095 steel and have put a lot of work in it. I'd like to know what your most reliable ways of treating 1095 are and if maybe you have any tips that would prevent warping or cracking. I've already had one successful bowie knife made from 1095, but I'd always like to learn more about heat treating. Thanks a lot. :D

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Here's my very non-scientific process (hillbilly heat treat):

Fill quench tank with 1 gallon veg oil. Heat a RR spike up to red and drop it into the oil. This heats the oil up until you can just barely stand to touch it with the tip of your finger. I'd say around 120-150 degrees.

Blade has been drilled, ground, and sanded to around 220 grit. Edge is about the thickness of a dime.

1. Normalize.

2. Normalize.

3. Normalize.

4. Back into forge, slowly heat to critical (nonmagnetic).

5. Quickly quench whole blade (edge first) in the oil.

6. Clean the blade up quickly. Clean the oil off and polish back to bright with the 220.

7. Straight into the oven for 1 hour at 425 degrees.

8. Out to cool to room temp.

9. Back into the oven for 1 hour at 425 degrees.

10. Out to cool to room temp.

11. Polish back to bright.

12. Differentially temper across stove eye on High; blue spine, bronze edge. Check edge hardness... you might need to draw it back some more.

Ready to finish.

Don

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Don A ... I have a question to your process..after you temper in the oven 2x isnt it tempered then?? to draw colors you are reheating the metal back up,doesnt that remove what treating you did???....wouldnt you be just as well just doing the oven OR using the differential treating.....

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Pete,

Yeah, once or twice in the oven would be fine I suppose, but I would have to go a bit hotter to get the edge soft enough. A couple things to note:

I use the kitchen oven. I have no idea what the exact temperature is is when the dial is set on 425. I only know that it leaves a blade of 1095 or W-1 a little too hard at the edge.

I have heard some of the guys that really know their stuff actually advocate a "triple temper". This is my modified version.

And yes, the differential temper on the stove eye alone would suffice, but I'm a slave to overkill. Anyhow, the differential treatment lets me "dial it in" without guessing if the edge is going to be too hard.

In all of this, if I am thinking right, I'm not going to damage the hardness I would achieve at, let's say 450... as long as I never exceed 450, once, twice, or three times. I have also read where the experts have said that you don't gain anything after three times.

That said, I've never bent any of my blades 90 degrees in a vice, but I've never had one fail under normal use. And they keep a good edge.

Don

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thanks for your reply! it is almost as unbelievable as the many recipies for flux, coatings, things you must do to weld...sometimes its hard to see thru the smoke....i havent made enough knives to lay claim to anything... i was aware if you dont exceed the temper temp you dont ruin it ..... i use a toaster oven that I also havent calibrated, although i will....i know if i do 1090 in it and lay it down more than 2x it warps...lol....so i made a little arrangement that holds the knife in the middle of the box edge down...i guess its close to the most even spot in the appliance...it worked... i have a hard time wanting to make one to destroy.... anyway good advice, thx again

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Pete,
That said, I've never bent any of my blades 90 degrees in a vice, but I've never had one fail under normal use. And they keep a good edge.


Bending 90 degrees in a vise is a test of your heat treating and blade design ability, not a benchmark of how real working knives should behave in the real world!

The only things I'd say about your HT routine is that 1095 needs to go a bit above non-magnetic, and it needs to soak for a few minutes to really get all the carbon into solution. This is hard to do well with primitive equipment, though. (I can't do it at the moment, which is why I prefer 1080ish steels.) As long as you're happy with your results, that's OK with me.

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I normalizing after forging at the industry standard (around 1600F) in order to get everything into solution and get the grains uniform. Then the blade is allowed to air cool until it is black, this will refine the grain. You have to heat past critical in order to get grain refinement. Anything else and you are just reheating the same grains. I perform more 3 normalizing heats, done at lower temps in order to bring that grain size down.

I anneal on the final normalization by quenching the blade and then repeatedly heating to a dull red. I can then grind, drill and pre-finish.

For the final heat treat I bring it to 1500F and hold for a 10 count or so... longer is better for 1095 (might as well use 1080 like Matt stated) but I'm working in a gas forge. I quench into an 8" dia x 34" deep tank with canola oil heated to 130F and keep the blade moving up and down for a count of seven and then interrupt the quench (about 450F) At that point it is safe to tweak into straightness if need. As soon as the blade is cool enough to hold for any length, I temper. I start out at 400F, check the hardness before bumping up the temp and doing it again. 3 cycles for one hour each.

This is not a magical formula, by any means. I did not invent this process. It is based on metallurgical principles. (with a little fudging on my part) I must give credit to folks like MS's Wally Hayes and Kevin Cashen for pointing me in the right direction as I stumble through all this.

Rick

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