MattBower

I think Frosty is just suggesting that it's not a very practical idea. Lots of work and experimentation to recreate a scaled-down version of an obsolete technology, to produce an obsolete product that can be still be obtained fairly easily, or made in other ways with guidance from people who are currently doing it (i.e., various kinds of bloomery smelting). With puddling I think you'd be pretty mucn on your own, since AFAIK no one is doing that nowadays. But there are a fair number of folks out there smelting bloomery iron nowadays. That doesn't mean that building a puddling furnace wouldn't be fun and educational, of course!

That's impressive, Sam. I think I'd have to see it to completely understand how you did the upsetting, but I like the result. Was that all done by hand, or did you use the Anyang for some of it? (I hope you used the Anyang!)

That's funny. I once got my charcoal kettle grill really hot, with a nice, thick bed of coals, threw a few steaks on, then put the lid on with the vents almost closed. A couple minutes Iater I lifted the lid to check the steaks and WHOOSH -- no eyebrows! After that I changed the way I lift the lid. Back on topic, I have carburized mild steel in much the same way by packing it in a container with charcoal and leaving it at the bottom of a big wood fire for a good 12 hours or more.

Before cold working it, or quenching it, yes. But when you heat the steel up to forging range that's going to relieve internal stresses, so normalizing beforehand doesn't do much -, if anything.

In my experience it tends to crumble more than crack at high temp. I'm not sure what causes it. Might be related to the fact that carbon lowers the melting point of iron. More carbon = lower melting point. (Not that you're actually melting your steel. I just wonder if the two things are related.)

I wouldn't bother trying to buy any of that tungsten alloy. If you could find it, I bet it'd be insanely expensive. (If I had known fifteen years ago what I know now, I would've brought a couple of those penetrators back from the desert out at 29 Palms, instead of the aluminum base of a tank shell.) I just posted it for general information. Those bolts sound interesting, though.

A while back I incorrectly said penetrators are made of tungsten carbide, and someone here (I don't remember who -- maybe rthibeau) corrected me. That got me curious, since WC was the only form of mostly-tungsten material that I was familiar with. In case anyone's interested, I'm pretty sure they're made of one of these alloys, or something similar: http://www.mi-techmetals.com/hd-typical.htm I bet that stuff is spendy!

Lately I've been using ferric chloride because it's faster than vinegar (about a five minute soak usually does it), and seems to be more thorough. It's not as safe as vinegar.

First, I wouldn't count on that rule of thumb about springs. I had one automotive coil spring tested and it was 5160. The only rule of thumb I'd count on is that springs are usually decent blade stock. Second, one of the hazards of salvaged steel is that you don't know anything about its condition. You seem to have considered the most likely heat-related issues that could be causing the sorts of problems you're experiencing. If it's not those (although it really does sound like you were overheating), I'm inclined to think the problem is the steel. It may have been badly overstressed at some point in its prior life. If the spring is damaged, I don't know a reliable way to work around that. Throw it out and try another one. Or better yet, try some new, high carbon steel. One of the frustrating things about learning on scrap is that it adds extra variables and makes it harder to figure out what's going wrong. Using new steel will usually eliminate some of those variables, which makes your life a little easier when a problem crops up.

Sam, as I said, I think it's very different when someone like you is standing over their shoulder and supervising, rather than attempting it on their own based on some advice over the Internet. That was my point: I did fly the helo correctly for 15 minutes, but I wouldn't have attempted it without that sort of close supervision. And if I had, it probably wouldn't have gone so well. I absolutely believe that you are capable of getting a new guy through making a functional sword, once, with your hands-on instruction and supervision. But it's not clear to me that that's what the average new guy here wants, or that he'll be willing to go out and find someone like you to walk him through it in person. However, henceforth, when people ask the question I will answer, "spend a week with Sam." Seriously, though, for the sort of people you're describing, I think something along those lines is a good answer. Personal, hands-on instruction makes a huge difference. I just don't know if most of the young guys who come here wanting to make swords will be willing to pursue that. It's not necessarily easy -- or free -- to get that kind of instruction from someone who knows what they're doing. But it's a good suggestion. I'll try to remember to mention it from now on.

The thing is, without a hardness tester to tell you whether your steel got full hard in the first place, it's all a bit of a SWAG anyway. Those look in the right ballpark, but rather than get hung up too much on a number that may or may not be accurate in your case, your best bet is just to test the tool and see if it performs the way you want. Unless you have a hardness tester, of course. :)

Thanks, Justin. I'm not going with titanium -- steel is stronger, you know -- but I am going to do with Dave B's suggestion of liners cut from an old hand saw, which should have suitable spring qualities. The prototype is a good idea; most of the tutorials (I've read some of them!) seem to suggest that.

Heh. I just remembered something. I once flew a helicopter for about fifteen minutes, with fifteen minutes at the controls of a T-34 as the sum total of my prior piloting experience. The fact that I'm writing this means it was a successful flight. Of course there was an expert instructor pilot sitting in the seat next to me, with his hands and feet inches from the controls, the entire time. Despite the fact that I have successfully piloted a helicopter once before, if I ever offer to take you for a helicopter ride, with me as the pilot, you should decline. :P

Sam, don't you think the fact that you're personally walking them through it and supervising the process might have a lot to do with the outcome? Are you completely confident that after a week with you, someone with little or no prior experience is ready to go do it on his (or her, I suppose -- but probably not ) own, properly -- without you standing over his shoulder, recognizing mistakes, and fixing them before they become problems?

I'm pretty sure the points on those are the tungsten carbide part. The rest of the tooth -- the part they're throwing away when the carbide wears out -- is likely steel.

People do incredible stuff with steel. You can spend more than a lifetime on it. Don't feel as if you're somehow "settling."

Yeah, old saw steel would be ideal! Wish I had one lying around. I might see if there's anything good on Craiglist.

I get where you're coming from, Steve, but I don't think it's quite as bad as you suggest. Sure, some people won't listen, and some will be pretty uncivil about it. But if you present the arguments factually and unemotionally, and try not to let it come across as condescending, some will listen. As for the uncivil ones, it's best to try to ignore them. The hard part is not sounding condescending when you've answered the same question twenty, fifty, or a hundred times. It's tempting to be very brusque about it, which can come across as, "I'm dismissing you because you're clueless," rather than, "I'm willing to help, but it's a big subject and you're going to have to devote a lot of time to self-guided study and practice to do this right. No is going to explain it all to you, and there's no substitute for experience." I realize the I-want-it-all-right-now-and-I-don't-want-to-have-to-exercise-any-discipline-to-get-it mentality gets harder to deal with as we get older, but I suspect we were all a little more like that than we'd care to admit at a certain age. If we try to stay positive and meet them halfway, some may have real potential. I'm pretty embarrassed when I look back at some of the attitudes I had when I was 16, 18, 20 years old. Fortunately, most people do grow out of the worst of it. And by the way, for the record (in case anyone is wondering), I haven't made a single sword yet. I'm still on knives. Probably will be for a good little while, too.

I feel compelled to add that there is a genuine and very serious safety issue involved in making swords. Most beginners don't understand that bad forging or heat treating technique can easily result in a blade breaking and scything off into space like a razor sharp steel boomerang, with the potential for very serious injury (or worse) if the flight path intersects with a human being. Yes, it's the individual's call whether to start making swords with little to no experience in bladesmithing and heat treating. It's also the individual's call whether to drive drunk. But in both cases, one alternative is objectively better than the other, at least in the vast majority of cases. (If you're an experienced amateur machinist with a degree in metallurgy and access to a heat treating furnace or a kiln, who's never made a blade before but wants to try a sword, you very well might pull off something decent on the first try. But that's a very different situation than that of the typical guy who pops up and says, "Hi, I'm sixteen and I've never worked with metal. How do I make a sword?") Just my $0.02.

I'm actually pretty confident that you could puddle in something the side of a medium size gasser with a high output ribbon burner (with a suitably shaped floor of high alumina castable). But I don't want to do it badly enough to invest the time and money. I have way too many half-finished projects going, as it is.

That depends what Ti alloy you would be using. You could get a rough idea by comparing the yield strength of your particular Ti alloy to the yield strengths of some steel alloys that you might use instead. 6Al4V titanium -- a common alloy -- has a "typical" yield strength of 120,000-130,000 psi. 1075 carbon steel at RC 53 has a yield strength of around 255,000 psi. That makes it about about twice as strong as 6Al4V. (Yield strength is the point at which the material plastically deforms -- i.e., takes a permanent bend. Tensile strength is the point at which it breaks. Since you don't want your sword to bend in use, I chose to compare yield strengths.) To my knowledge the people who have managed to forge weld Ti to steel have done it in a sealed canister filled with an inert gas, like argon. You would need a press, preferably hydraulic. If you misjudge the temperature there is a very real possibility of burning, liquid titanium squirting out of the canister. Ti burns at around 4000 degrees F and is very difficult to extinguish.

(1) If you made it to "standard" katana dimensions, it would be weaker than a fully hardened, properly tempered, monosteel blade of a good quality, modern alloy steel. It would be lighter than the all steel blade, but it wouldn't be stronger. As recently mentioned here, Ti alloys (generally speaking) are stronger than steel by weight. But they're considerably less dense than steel, and by volume they're generally weaker. (2) Forge welding Ti to steel is extremely advanced stuff, and quite dangerous to boot. Can it be done? Yes. Can it be done now, by you, with "zero experience"? No. (3) Folding modern, essentially homogeneous metals does not make them stronger. At best it'll do no major harm to steel. At worst it'll result in severe grain growth, intergranular oxidation, decarburization and weld flaws, and you'll end up with something far inferior to what you started with. Folding and welding was a way to improve the crude, slag-laden steels and irons of the past.

We had some discussion about that late last year. I thought for a while that Grant Sarver was going to take the bait and make a little one . . . :)

Well, if it came out really nice with mild steel liners, I'd be very happy! I have nothing against steel. In fact I like the stuff a lot! It's just a question of whether there's some reason I can't make a really nice knife with mild liners. I have some. Considered it. Seems a little thin, maybe. ?

I'm working on my first folder. Probably very stupidly, I've decided I'd like to try a linerlock. I don't have any Ti, or any medium or high carbon steel that's an appropriate thickness for liners. Forging down thicker stock is an unattractive option because of the work involved in getting it sufficiently flat to make good liners. So I was thinking of cutting my liners from a broken power hacksaw blade I have. It appears to be a bimetal blade, since the teeth are harder than chicken lips and the back won't harden in water. (It may have some alloy content, but the basic point is that it's fairly low carbon stuff.) I was planning to cut the liners from the back, which is about 1/16" thick. Do any of you more experienced folder builders think mild(ish) steel can't work in this application? I realize it has serious limitations as a spring material, but it's thin stuff and it won't be flexing very far. It won't be as strong as a better quality spring, but I suspect it'll still be strong enough. Am I wrong?