another heat treat thread

[ginshun]

So lets assume that I am doing my own heat treat using an old wood stove, and quenching in automatic transmission fluid or some other readily available oil.

What steels would be the best for me to stick to? My first knife was made from 1095, and it seems to me to have worked out fine, but based on info that I have since read here, 1095 seems a little bit iffy for my primitive methods. I have since ordered myself a bar of 1080 which is supposed to be a little more forgiving.

Can you guys list off a few more steels that should work relatively well with my minimal set up? Sooner or later I will get more equipment, like a temperature gage of some kind, some proper quenching oil maybe a real forge or heat treat oven, but for now I have what I have and want to get the most out of the knives that I make using what it available.

Can I assume that the lower 10XX steels (1050 to 1084) are pretty much all OK? Also that all other things being equal the lower ones will be tougher but not hold an edge as well while the higher ones will hold an edge better but not be as tough? Any other carbon steels that would work out OK? Any tool steels?

 

[galadduin]

I've never used a steel apart from air hardening ones with success, but if i wanted to make knives in my old charcoal forge I would select 1084, W1 or O1 as they are simple enough to quench. I had no success on 1095, tried couple of times but always got ping or warp (without god HT oil I had no choice but water or brine)...

 

[LRB]

Those you list are pretty much your choices. In my opinion, 1084 is going be your best. Let me add, that most do not give it enough heat, and do not soak it long enough, if at all. You should take it about 50°, to 75° beyond non-magnetic, and if possible, a 5 minute soak without over heating. Even just a couple of minutes is better than none. A 425° temper will give you a nice blade. 450° will give you a nice blade, and be a tad tougher. Depends on it's primary intended use. You should not play with 01, until you have a good means of heat control. It is not a simple steel, Besides, 1084 is much cheaper.
Unofficially, off the record, and not to be taken as a recommendation. 01 seems to hold an impressive edge, compared to many lesser steels, even with a backyard HT. Bear in mind, it may, or may not be a tad brittle. It may or may not be really tough, it may or may not have soft spots, but even so, it seems to cut pretty good. I have to believe this factor is due to the multiple alloys in it, but you will never get it to it's best, without heat control, and established methods of HT for it.

 

[ginshun]

What happens if you overheat them? How do you know if it has been overheated? Like I said, I don't really have a good way to judge the temp at this point. I have no problem getting it up to non-magnetic, but I have no idea how hot I could actually get the stuff.

And as far as the steels go, I will probably use 1080 or 1084 as long as I can get it in the sizes that I want. Anybody know where to get some thicker stuff in either of those, like 5/16 or 3/8 x 1 1/4 or 1 1/2 bars? I have a sharpened pry bar / throwing spike thing project for a friend that I want to use a thicker piece of steel for. 1/4" might work, but I'd like something even thicker. This piece could probably even be quenched in brine or water safely.

 

[galadduin]

The colors are your only friend unfortunately if no thermocouple available. The magnet only tell you you are just below from right temp but you have to get used to color. It is important to work at night and same ambient light and same forge. Takes time to master (I know because I couldn't - Ok a couple of knives with success but many have gone to trash)

 

[Dan Zawacki]

Even with no other resources, you can learn to guage temperature by eye. Overheating the steel can have a variety of negative impacts from runaway decarb, where carbon leaves the steel en masse, leaving at least a skin of soft stuff that won't get hard, or even worse, red short steels can crumble and fall apart if you burn them!

The best advice I was ever given on judging heat by eye is this:

1: keep your shop as consistantly lit as possible. You are going to try and judge the temperature of the steel by the color it is glowing. In bright daylight, 1400 degree steel can look black!

I do all of my heat treating in my shop at night, with a specific worklamp pointed into the far corner of the shop, which keeps a very consistant and low level of light. Just enough for me to see well enough to work safely, not enough to ruin my eye for the steel.

2: watch the decalescence. I'm pretty sure I spelled that word wrong. Even so, the point is a good one. By learning to spot and watch the shadow line move across the steel, you will be able to judge where the steel is in soloution. Just on the hot side of this is the color you're after. You can use a magnet as a bit of a teaching aid to tell you you're getting close, but the point at which the steel is becoming non magnetic is actually a bit cooler than where it goes into soloution. Use the magnet to tell you you're getting close, and can start slowing things down and watching for that shadow line.

one word for the very beginning: 1084

Higher or lower gets a little more complicated. As you bring the carbon content away from the eutectic, some pretty nifty (as in intriguing, but not necessarily good or bad) things begin to happen. If you want tougher, you can temper at a higher temperature, if you want harder, you can temper at a lower temperature. That is not to say you're going to run into problems with 1075, 1070, or even 1060, but the question I would ask is; with such a great source for 1084 right here, at rather decent pricing, why, as a beginner, would I forge anything BUT Aldo's 1084? In this way, I know that I got a good deal on the best steel a beginning smith could hope to learn on!

That is, of course, assuming you are going to be paying for steel of known content. A lot of guys get a great kick out of using leaf springs, files, wrenches, and all sorts of other stuff to forge into blades. Hey, if it works for them, GREAT! But as a beginner myself, I can't justify the idea of trying to figure out what I'm trying to make a knife out of, what with all of the other stuff I'm trying to learn!

I find the economy of using improvised materials a false one. Don't get me wrong, I'm pretty much broke, so pricing is very important. However, I have to look at the minimal cost of things like known steel, and good quenching oil as what I call minimum investment to learn the craft effectively.

Sure, a lot of great knifemakers muddled through the mystery steel and oil based goops and learned to make incredible knives doing so. What can I say, I don't have that much faith in my actually having any real talent for this. I'm fairly sure that I would waste enough time, energy, and indeed money by junking too many blades and being frustrated for too long. I would rather just know that if I screw something up, it is exactly my own fault, and not the fact that this file turned out to be from the one run that the company made out of a radically different steel, or that maybe my quench might be fast enough, but maybe not.

By biting the bullet, making some sacrifices, and saving my pennies for some steel and oil, I am at least able to rest assured that when things don't go as planned, there's many fewer places that could be the reason. If I were to try the other approach, I would eventually (as in pretty quickly) have spent more money on different jury rigged these, improvised those, and recycled the other things, trying to find a combo that worked to my satisfaction. After all that, what would I have learned? Probably not much of real use in the long run, except that I hate being frustrated at not knowing what went wrong more than I hate being broke.