HondoWalker Posted October 8, 2021 Share Posted October 8, 2021 So I bought a bar of 1/8 x 1.5 in x 48 in just to play with. Last time at the forge I put a point on a piece and later sawed out a tang. It's at the point where it needs quenched and tempered. I don't want to waste coal on a useless temper. The price tag had nothing but size information on it. What I'd like to know is this steel going to harden after a quench? I've already made 10 knives that aren't hard. I don't want to make any more soft knives. 4 hard out of 14 is a pretty poor record. Link to comment Share on other sites More sharing options...
Frosty Posted October 8, 2021 Share Posted October 8, 2021 Buy steel from someone who sells blade steel. Haven't people here suggested this to you a few times now? Evaluating a steel's suitability for blades BEFORE making a blade has been suggested as well. Frosty The Lucky. Link to comment Share on other sites More sharing options...
ThomasPowers Posted October 8, 2021 Share Posted October 8, 2021 Random steel sold at "box" stores is almost always A-36 and while you may sometimes get some that will harden a bit, especially with aggressive quenchants, it will NOT make a good blade. Meanwhile you could have bought a decent knife steel for scrap price if you didn't manage to get it for free. As this has been discussed many many MANY times on IFI I'm sure you can dig out the info without having us repeat it yet again. As High Carbon Steel, costs more to make, is trickier to work and requires thermal processing after working; you don't find it being sold for general use at box stores. Link to comment Share on other sites More sharing options...
George N. M. Posted October 8, 2021 Share Posted October 8, 2021 Hondo, probably the best places to get good blade steel are either an actual steel supply firm or from a blacksmith supply firm. The internet outlets will probably be more expensive but you will know for sure what you are getting. Of course, things like scrap springs can be used but you have the risk of it being some weird alloy that doesn't harden the way you expect or has microfractures from long, hard use. Lots cheaper but you pays your money and you takes your chances. The hardest you will get mild steel is to use "super quench" (you can look up the recipe on any search engine) and no tempering. It is surprisingly hard for mild steel but still not as good as real higher carbon steel. Also, you tend to pay a very high amount per pound at a big box or hardware store for mild steel. However, I recently noticed a rack at my local hardware store labelled "piano wire" up to about 1/4" in diameter. Piano wire is traditionally fairly high carbon steel. I may get a piece and experiment to see if it will harden. It's pretty small but there are times when you want a stronger than average rivet and a small blade could be made of 1/4" and it could be stock for a small pattern welded billet. "By hammer and hand all arts do stand." Link to comment Share on other sites More sharing options...
Frazer Posted October 9, 2021 Share Posted October 9, 2021 Agreed on everything said above. I know you can only make runs for material every so often, but any of the raw stock you'll find at a big box store is generally going to be sold as "weldable" steel. That is code for (overpriced) structural steel. However, there are other items in the store that aren't sold as flat/bar stock that could be used.. Whether they're cheaper than buying a bar of a known starting material online or at a steel supply is questionable, but I'll put that aside for the moment. When selecting a mystery steel it can be helpful to consider what it was used for in the past. To name a few examples, it's fairly safe to assume something like a file, spring, chisel, crowbar, lawnmower blade, etc. is going to be made out of some sort of hardenable steel or other. It was once hard (or at least hard-ish) so in theory it can be returned to that state. Is this a guarantee that every lawnmower blade is going to be ideal for any type of knife? No.. but that's why you test mystery steel first. If you're buying flat stock new and neither you nor any of the employees in the store know what alloy it is then it's safe to assume it's A36 and not suitable for making knives. If it's mystery steel that you're looking to repurpose, try to pick "tool steels". In this context I mean steels that are intended to perform a particular set of tasks where an increased hardness or toughness would be beneficial. Link to comment Share on other sites More sharing options...
George N. M. Posted October 9, 2021 Share Posted October 9, 2021 Frazer makes a good point to consider when acquiring steel that isn't sold as raw stock. Consider its intended use. A file will be hard. A pry bar or tire iron will be tough. A spring is "springy." All these require a certain amount of carbon in the alloy. Sometimes, particularly with springs, there can be other things which make the metal unsuitable for a blade smith but that is why you test scrap steel before you put time and work into it. This is why we are so interested in spark tests, grain structure, hardenability, and how a piece will fail when tested. And remember, hard does not equal good because hard also usually equals brittle. "By hammer and hand all arts do stand." Link to comment Share on other sites More sharing options...
HondoWalker Posted October 9, 2021 Author Share Posted October 9, 2021 I know there are better places to get steel. It just happens that the Dollar store and Tractor Supply are right next to each other and my wife had needed to go there. I had saved up enough money to be able to buy a cheap piece of steel and took the opportunity. I can't just go anywhere I want or need to. I don't have any money either. I don't get any disability money. She draws too much for me to get anything. That puts me at her mercy both financially and transportation. I'm lucky to get what little I get. It was nice when I was younger and made a fat wad of cash every week. I could play as hard as I worked and I didn't worry about much of anything. That was 7 strokes and 3 stents ago. I figured the steel wouldn't be good when I bought it. It was either buy it or do without. I'll go ahead and glue it up and polish it a little and chalk it up as another practice knife. Link to comment Share on other sites More sharing options...
Frosty Posted October 10, 2021 Share Posted October 10, 2021 If you can't save $20 to order good blade stock online they perhaps you want to shift your goals from working blades. Nice wall hangers might sell for enough to buy proper blade steel. Be well. Frosty The Lucky. Link to comment Share on other sites More sharing options...
ThomasPowers Posted October 11, 2021 Share Posted October 11, 2021 Bottle openers can keep you in high grade ordered online blade steels. I have run across case hardened files, imported of course and lawnmower blades that wouldn't quench harden---the newer boron alloys designed to not chip or shatter. In 40 years of smithing I've actually run into *1* leaf spring that was "low alloy strain hardened" steel and wouldn't quench harden. Scrap Yard Rule: TEST BEFORE YOU USE! Link to comment Share on other sites More sharing options...
Purple Bullet Posted October 13, 2021 Share Posted October 13, 2021 The thread got me thinking; What would happen if you made two identical mild steel blades, applied a case hardening to one side of each using something like Cherry Red and forge welded the two pieces together with the hardened sides in the middle? If the hardenability survived the weld (doubtful?) you might end up with the proverbial self-sharpening knife. It would essentially be the same as a san mai, but with a VERY thin hard center. If you could figure out how to keep track of the hard line while you grind, that is. Link to comment Share on other sites More sharing options...
pnut Posted October 13, 2021 Share Posted October 13, 2021 I just bought a file off the clearance rack at TSC that I suspect is case hardened. I'll find out before I try to make anything from it. Until then it'll be a hot file. Pnut Link to comment Share on other sites More sharing options...
Goods Posted October 13, 2021 Share Posted October 13, 2021 4 minutes ago, Purple Bullet said: If you could figure out how to keep track of the hard line while you grind In this case, you could find the hard center by filing it down. Not sure it would work though, that fine line of harden able material would probably diffuse to a medium-low carbon line due to carbon migration at welding temperatures. David Link to comment Share on other sites More sharing options...
Frazer Posted October 13, 2021 Share Posted October 13, 2021 I wonder if the cherry red would survive forge welding temps. Carbon migration would certainly be be an issue... In any case, cherry red will also not make mild steel as hard as I would want a knife to be. Link to comment Share on other sites More sharing options...
Purple Bullet Posted October 13, 2021 Share Posted October 13, 2021 Agreed. However, think of the case of the young kid (or not so young for that matter) that never learned how to sharpen. If you have a very thin hard center and soft outer layers, the outer layer would wear, leaving the hard center which would probably chip over time, but then the outer would wear again. I've heard that back in the day when sugar cane was harvested by hand that the cane knives were sometimes hardened on one side with hard surface rods and ground down flat again. Thereafter they would self sharpen by normal use. I haven't verified that, but I guess its possible. Link to comment Share on other sites More sharing options...
Frosty Posted October 13, 2021 Share Posted October 13, 2021 pnut: An easy way to tell in a file is case or quench hardened, if you're going to use it as stock is to clamp the end in the vise, cover with a rag and give it a tap with a hammer. If it's hardenable steel it'll break. Won't work on the tang, they're tempered so as not to snap in use. Case hardened won't break without getting carried away with a hammer if then. Frosty The Lucky. Link to comment Share on other sites More sharing options...
ThomasPowers Posted October 13, 2021 Share Posted October 13, 2021 Cane, with a high silica abrasive built in, should wear a blade faster and since hardening makes steel wear slower, differential wear might be a factor. Interesting. I turned down a file last Saturday at the scrapyard due to the India stamp. I've had bad experiences with them in the past and have *pounds* of old files already at home. Link to comment Share on other sites More sharing options...
Frazer Posted October 13, 2021 Share Posted October 13, 2021 PB, Assuming you could find a treatment that could sufficiently harden the surface steel and not migrate at forge welding temperatures then I don't see why it wouldn't work. It'd be like a San Mai, but with a really thin center layer. Link to comment Share on other sites More sharing options...
Goods Posted October 13, 2021 Share Posted October 13, 2021 Might try a Go Mia with mild steel sides, thin layers of nickel sheet, a bandsaw blade as the center, then draw the billet out to get the center real thin. Could make for an interesting result, but I can’t see myself doing it. My list of things to try is too long for my shop time as it is now. David Link to comment Share on other sites More sharing options...
George N. M. Posted October 13, 2021 Share Posted October 13, 2021 I think a major difficulty with having a thin, hard area in the center of the blade is getting it aligned exactly on the edge as you were forging and grinding. I'm assuming that there would be no color or other visual difference between the softer and harder zones. "By hammer and hand all arts do stand." Link to comment Share on other sites More sharing options...
Purple Bullet Posted October 13, 2021 Share Posted October 13, 2021 Goods - I feel the same way, but sometimes my curiosity gets the better of my priorities. That's one of the nice things about being retired and refusing to take money for my "work". George - it would be a problem. I wonder if acid etching would show the line? It would only work if the forging was consistent on both sides. I'm not sure my skill level is there but that won't stop me from trying. Right now a church sign is keeping me from trying. After the storm a lot of businesses are having a hard time getting back going and are dealing with backlogs. Link to comment Share on other sites More sharing options...
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