o-1 temper/heat treat

[Black Dog]

Thanks for the information on heat treating.
Fitzo, thanks for the link to the soak time discussion. I felt smarter before reading through that. I guess there are a lot of variables and opinions about this. If it were all easy and straightforward there wouldn't be much to discuss. I am feeling like I should use something more precise, like a heat treating oven. Maybe that would take some of the variables out of the process. I wish this were not the case, but I just don't have too much time to experiment and screw up blades that I have spent a fair amount of time on hammering and grinding.

 

[fitzo]

Black Dog, the whole intent behind threads like that is to be able to know the facts and become able to make informed decisions.

Cashen has stated frequently that, while there may be many opinions, there is only one set of facts.

One fact is that good temperature control allows for better manipulation of what you want the steel to do.

Not everyone can afford that fancy temp control. So what to do? Learn enough to know how to make the best knife possible with the tools you have available. If you can't manage to soak a steel at a specified temp, then one informed choice would be to work with the steels that don't need much of any soak and where the magnet thang is actually the right temp to quench at. 1075/1080/1084. Learn to do "normalizing" well to get good grain structure and then harden and temper it properly and those'll make a very decent blade, close to all it can be.

By the same token, if using a steel that you know would benefit further from a longer soak but produces a blade that meets your needs and satisfies you using the tools you've got, then that's okay, too. "It meets my needs" is an opinion and ok. "It's everything it can be" needs to be made under certain conditions and is something verifiable by scientific testing. "It's everything it can be with the tools I have available" will hopefully lead to an honest evaluation of how it fallsl in between those. The idea is to know the difference between them through education, experience, and self-honesty.

 

[SteelSlaver]

On the magnet part I attach a magnetic scribe to the blade a bit back from the edge (1/4") , if a large knife I use more than one scribe, I apply the tip of my flame to this area a bit back from the edge and it reaches non magnetic the magnets will slide towards the spine.
QUOTE]

As a magnet heats it will begin to lose its magnetism...If I have understood your post correctly, .... placing magnets on the blade the way you describe may not necesarily indicate the temperatu......re your wanting.

If using a magnet then it should be kept seperate from the blade and only used to momentarily touch the blade to find out if the blade has reached critical/non magnetic.....Its accuracy depends on catching the point of loss of magnetism as the temperature is being raised.

What is happening with my method is the edge area looses magnetism and the magnet is attracted to the thicker area near the spine that is cooler and still magnetic. I get some soak time by starting to move the blade away at this point and keeping my color as the magnet works its way up the blade and it will because the heat travels up and helps soak up heat to avoid over heating. I am only attempting to totallly harden the edge and I get some very nice harmons and good edges. I use 5160, 1095, 1095/nickel and 1095 15n20 damascus. Nothing real exotic here except the damascus part

 

[me2]

I hardened my first successful knife using Mapp gas, a one brick forge, olive oil and the kitchen oven. It was acceptable for a first try. It got very sharp, and the guy I gave it to said it made it through his sons only deer that season with just a touch up. A scrap piece treated the same way came out to 57-58 on the hardness tester at work. I tempered a little higher than 400, 450 I think. If I were to do it again (I ran out of O1 and switched to 1095) I'd probably try a trip to the freezer straight from the quench, then temper at 350, then repeat the freezer/temper. Double or triple quenching probably wouldnt hurt, but I didnt try that, so I wont speculate. The lower temper and freeze should result in a hardness of 63-64. Of course this was a dedicated hunter, so even the higher temper couldnt be batoned and such.

 

[Gene Martin]

Black Dog,

If you don't make the time to do some testing, you may well find that all the hammering and grinding you did was a waste of time. A bad herat treat will screw up an excellent piece of steel. If these are just for you to fool around with, it's no biggie. The first time that you sell one, though, you may end up souring someone on all custom knifes, not just yours.

I encourage you to slow down and take all the time necessary to produce the best blade you can. You learn a lot more about the steel, as well as what works and what doesn't. And yes, sometimes it takes breaking a perfectly good blade to find out whether it really was.

We all hate to throw time and money away, but hoping for the best doesn't always produce it. Slow down, learn to really do it right, and then take pride in your work based on what you have learned and applied, not because it looks good.

The very best of luck with your learning. We all get to walk that road.

Gene

 

[Black Dog]

Gene,
Your comments provoked some thought about it all. I suppose that I could do some tests on "knife like" pieces of steel (pieces that are never intended to be a finished knife, but sort of the same thickness and shape) just to see how the steel works without the initial investment of time. I have sold some knives that were heat treated by experts and have no worries about the quality of those knives. As you say I would hate to sell a knife to a customer that was the result of a bad heat treat. Time to get on with it, and start experimenting with pieces that have no investment of time. I can use some of the steel bananas that were a result of learning how to hammer hot steel. I knew they would be good for something .

 

[Gene Martin]

Black Dog,

After the OKCA show in Eugene, Wayne Goddard used to have an invitational lunch the next day. His wife's first bout with cancer precluded more, but they were fun. There were a bunch of smiths there, some with big names, some with not so big names. It was instructional beyond belief.

At one such meeting, Rick Dunkerly took out a finished 52100 blade, that was handle ready, and that had been bent 90 degrees and straightened cold. Because we were talking about testing, Rick took the knife, put it in a vise and bent it 90 degrees again. Then 180. On the 7th 180 the edge chipped. On the eigth 180 it broke. That's sacrificial testing at it's finest and showed a really good heat treat on a good steel.

Wayne had a blade that a maker who was getting a lot of press had come by with, testing for mastersmith. The tang had broken off as they began the bend test. Wayne brazed it back on and the test continued. The blade broke. Now this maker had been to the ABS school, same as a bunch of us, and had a master smith mentor. He was getting a lot, and I do mean a lot of press because of some unique things he was doing at the time. His knife was not heat treated properly. His second test blade, after going home and working on it, broke as well.

So we saw 2 grads of the ABS school with their test kniives. The owner of the broken blade was not present, but his blades were and we knew who it was. Both makers knew, having been taught, how to do it right. One maker, Rick, tested regularly. The other didn't.

There are two results. The first is that testing produces known results and confidence. The second, less observable, is that a bunch of people bought knives from maker B, having believed the magazine articles and having confidence because of maker B's training. They received an inferior knife. It was pretty, but failed to meet the established standard. Had maker B's name been mentioned or written up about this, his values would have fallen like a meteor. And deservedly so.

My original post was to encourage, not criticize you, and I hope you took it in that light. It was intended to provoke in a positive manner so you'd be a better smith. I hope it did. Start testing however you want, but make them tough and pretty, not just pretty. Testing makes the difference. That and making sure that you heat treat things very well. Testing shows that first.

Again, good luck on your forging. The skills grow with time and testing. You've been bitten by the bug, so have a ball. It's a wonderful thing to take an ugly piece of steel and create something beautiful from it.

Gene

 

[Phillip Patton]

There are two results. The first is that testing produces known results and confidence. The second, less observable, is that a bunch of people bought knives from maker B, having believed the magazine articles and having confidence because of maker B's training. They received an inferior knife. It was pretty, but failed to meet the established standard. Had maker B's name been mentioned or written up about this, his values would have fallen like a meteor. And deservedly so.

Gene

What established standard??? Being able to bend? I thought the standard for knives was that they cut.
The ABS requirement that a blade be able to bend 90 degrees is simply to show that the maker knows how to heat treat steel. It doesn't mean that a knife that won't bend is inferior.
Most of the knives I make (and sell! And I haven't had ANY complaints yet!) are hard all over. My customers know this, and want it that way. Most of them have been knife users for a long time, and know what works and what doesn't.
One of my customers (who is in the military, and uses his knives hard) told me he bought a knife from a MS (he told me who it was, but I won't repeat it) and tried to hammer the blade through some wood (he was in the jungle at the time), and the soft back started disintegrating. He actually sent the knife back and had the maker re-heat treat it with a hard back.
You say that maker B's customers recieved an inferior knife. Maybe, I don't know who you're talking about, so I can't judge his knives, but by saying he makes inferior knives because they won't pass the ABS bend test, you're implying that those of us who don't differentially heat treat are also making inferior knives.
Your free to feel that way, and even say so. I really don't mind, I just wanted to give an alternate view to those reading.

 

[warrior24]

Well dose'nt every knife excel in its own way. Just like you can use a straight screwdriver for a Phillips screw but a Phillips screwdriver is better suited. As I have understood it is some knives are better flexible, for some applications. And rigid knives are better for Others. Please pardon my corny comparisons but this is how I see it.

 

[Gene Martin]

Phillip,

I was being very narrow in regard to this thread. I do more stock removal than forging because I do blade blanks in ATS34 and D2. I absolutely agree with you. The ABS test is to show a knowledge of properly heat treating oil hardening steels, specifically 5160. The example used was between ABS trained makers and comparing apples with apples.

A knife is a life support system for a cutting edge. That system can be implemented a number of ways, but that's all it comes down to. After that it's using the best knife for the task at hand.

Sorry if i seemed to be really narrow on this, because I'm not. It all comes down to the best heat treat for the steel being used.

Warrior24, you missed the point. It's about proper heat treating. Neither screw driver will do much good if it twists off the first time you use it, especially if you are only half done. A knife can have a general use style, or a specific use style. A fillet knife needs to flex, yes, but it also needs to come back straight and hold a decent edge. Most knives will do whatever job is put before them, to a point. I once used a Gerber boot knife to field dress a deer. Not the best but it worked. If it had gone dull halfway through, or broken off because it was poorly heat treated, it would have been a problem.

Gene

 

[Matthew Gregory]

I think it's important to mention here that the ABS doesn't necessarily take the stance of the differential heat treat being a superior method, or that anyone that's commented so far maintains that view.

I think it's also important to post Tim Zowada's demonstration at Ashokan here, to help shed some light in this matter.

Thanks to Chris Meyer for this, and his permission for letting me repost it every chance I get!Tim's demonstration