Blood Groove Posted March 27, 2009 Share Posted March 27, 2009 Hi. I had a designe for a knife, and it incorperated the pry head of a crow bar as the butt of the knife. I had been making it for about a month, and then I got to the heat treating. Saddly the knife broke during this process. That stuff is hard! We didn't even get it up the the critical temperature when we put it in the water to treat it, but it broke anyway. Usually we heat treat in oil, but were experamenting with a salt water. This was also an old Crow bar. Probably made in America:D So my question is do any of you know what metal it might have been made from, and if so how do you harden that metal. We were thinking that it might have been an air hardened steel or something. Any info on this is going to help with my next attempt. Thanks. Quote Link to comment Share on other sites More sharing options...
archiphile Posted March 27, 2009 Share Posted March 27, 2009 Not sure as to the make up of the steel that you were using. I might suggest that you go to your user CP and edit the location so that we might have an idea of your 20. You never know, there might be a smith close to you who can provide both online and in-person support. Incidentally what branch of the service where you in?(if you don't mind me asking.) I was served in the Marine Corps. PM me we can "talk shop". Quote Link to comment Share on other sites More sharing options...
Blood Groove Posted March 27, 2009 Author Share Posted March 27, 2009 Well I thank you for your service in the Marine Corps. I'll always respect someone who's served their country. I'm kind of embarrassed to say that I wasn't in the military. What was it I said that made you think I was in the service? Quote Link to comment Share on other sites More sharing options...
archiphile Posted March 27, 2009 Share Posted March 27, 2009 Your avatar and your name. While I realize what a blood groove is and that your are a bladesmith, the combination of the two just got me to thinkin....I know look out Archiphile is thinking again. Best, Archiphile Quote Link to comment Share on other sites More sharing options...
Blood Groove Posted March 27, 2009 Author Share Posted March 27, 2009 Ah I can see that mistake being made. Well, no worries, I really consider it a compliment that you thought I was in the military I did name myself Blood Groove after the one in my Ka-bar though. haha Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted March 27, 2009 Share Posted March 27, 2009 Funny I was just working a student through a project last weekend---a knife made from an old crow bar I picked up at the fleamarket. Now of course you gave us all the details like the level of finish and thickness of edge before quench and the temp/colour you quenched at right? They make a difference on how a piece quenches. Anyway since this was junkyard steel I of course had my student reserve a piece of the original stock and forge it down to blade dimensions and did a cleanup on it to get a test piece for heat treat testing---you don't want to have a learning experience on the real blade right? So we heat treated it in plain water---not usually my first test, warm oil would be that; but crow bars are often medium carbon steel and it was the test piece and so we would know to go oil if it reacted badly and could try it again in brine if it was ok in oil. No problem with water but it was a bit softer under the file than I liked so I tried brine last Sunday and it came out nicely! The sample piece was the end with the nail puller and when forging it down it just became a "fish knife" with the nail puller being the flukes that are the tang---I didn't harden the flukes as they had been left rough ground. It's self hilted with the flukes resting in your palm and thumb and forefinger in indents right before the blade starts---looks like it would make a skinner with a curved blade. May be several reasons you had trouble: too hot when you quenched it, too thin when you quenched it, rough finishing marks that can propagate a crack or as you suspect wrong quenchant for that alloy. Spark test it to get an idea of the carbon content and compare it to a set of known standards, (1018, HC RR Spike~1030, file--1095, etc.). Very unlikely to be an air hardening steel---why pay $$$ for a piece of steel that needs to be tough but will only sell for $; but spark testing will tell you. Also as a used piece it may have suffered damage---why I saved the nail puller and curve for the test piece---most likely to have been stressed or hammered on. Quote Link to comment Share on other sites More sharing options...
Mike Ameling Posted March 27, 2009 Share Posted March 27, 2009 Don't know what steel, but one suggestion on the heat-treat. Before your final heat-treat, do something called Thermal Cycling of the blade. To do this, you heat it up to critical temp, pull in out of the heat, and let it air-cool until you don't see any red color in the blade. Then put it back into the heat and do this 2 more times. They heat it back up to temp and quench. Thermal Cycling helps remove any internal "stress" put into the blade in the forging/bending process. It also "refines" the grain structure of the steel - shrinks the grain structure. When you heat the steel up to forging temps, the grain structure expands. Thermal Cycling reduces the size back down. This will make the final steel much less "brittle". It's a little tip I learned from a knife maker. He suggested it when I was having problems making Flint Strikers, and having them be too brittle after heat-treating. Hope that helps. Mikey - that grumpy ol' German blacksmith out in the Hinterlands Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted March 27, 2009 Share Posted March 27, 2009 Actually "thermal cycling" is anytime you heat it up and let it cool (or cool it and let it warm---thermal cycling)---that includes the heat and quench. Normalizing is what you do to refine grain---and pretty much done as you mention it though most folks let it cool further that till the red's gone. Heat treat for a blade usually goes something like: Normalize 3 times Heat and Quench (usually one time though *some* alloys will profit from multiple times) Draw Temper 3 times Some alloys will also profit from a cryo treatment followed by tempering again Quote Link to comment Share on other sites More sharing options...
Steve Sells Posted March 27, 2009 Share Posted March 27, 2009 (edited) read the sticky's on heat treating, you may be surprised to learn start with air quernching, then try oil, only then water on a unknown steel, once you find water is too fast, its broken already, where as oil not hardening can move on to the more severe quenches. as some steel tend to explode if water quenched. Edited March 29, 2009 by steve sells typo Quote Link to comment Share on other sites More sharing options...
Dodge Posted March 27, 2009 Share Posted March 27, 2009 Ah I can see that mistake being made. Well, no worries, I really consider it a compliment that you thought I was in the military I did name myself Blood Groove after the one in my Ka-bar though. haha I don't mean to get into a big long discusion about the term "Blood Groove" ('specially since it's OT) but the groove in the Ka-Bar and just about any blade with a fuller is there for weight reduction and strength. Nothing more. I have to agree, though; "Blood Groove" is a pretty cool term. Misnomer, but still cool :D Quote Link to comment Share on other sites More sharing options...
Blood Groove Posted March 29, 2009 Author Share Posted March 29, 2009 Don't know what steel, but one suggestion on the heat-treat. Before your final heat-treat, do something called Thermal Cycling of the blade. To do this, you heat it up to critical temp, pull in out of the heat, and let it air-cool until you don't see any red color in the blade. Then put it back into the heat and do this 2 more times. They heat it back up to temp and quench. Thermal Cycling helps remove any internal "stress" put into the blade in the forging/bending process. It also "refines" the grain structure of the steel - shrinks the grain structure. When you heat the steel up to forging temps, the grain structure expands. Thermal Cycling reduces the size back down. This will make the final steel much less "brittle". It's a little tip I learned from a knife maker. He suggested it when I was having problems making Flint Strikers, and having them be too brittle after heat-treating. Hope that helps. Mikey - that grumpy ol' German blacksmith out in the Hinterlands Thanks! That's a very interresting piece of information. I'm definitely going to give that a try for my next knife. Quote Link to comment Share on other sites More sharing options...
Blood Groove Posted March 29, 2009 Author Share Posted March 29, 2009 I don't mean to get into a big long discusion about the term "Blood Groove" ('specially since it's OT) but the groove in the Ka-Bar and just about any blade with a fuller is there for weight reduction and strength. Nothing more. I have to agree, though; "Blood Groove" is a pretty cool term. Misnomer, but still cool Yes, actually I've read that. It's more of a strength thing (think of the designe of an "I" beam) instead of a providing a space for the blood to flow out thing. Thanks though, I do think it's a really cool name haha. Quote Link to comment Share on other sites More sharing options...
Blood Groove Posted March 29, 2009 Author Share Posted March 29, 2009 Funny I was just working a student through a project last weekend---a knife made from an old crow bar I picked up at the fleamarket. Now of course you gave us all the details like the level of finish and thickness of edge before quench and the temp/colour you quenched at right? They make a difference on how a piece quenches. Anyway since this was junkyard steel I of course had my student reserve a piece of the original stock and forge it down to blade dimensions and did a cleanup on it to get a test piece for heat treat testing---you don't want to have a learning experience on the real blade right? So we heat treated it in plain water---not usually my first test, warm oil would be that; but crow bars are often medium carbon steel and it was the test piece and so we would know to go oil if it reacted badly and could try it again in brine if it was ok in oil. No problem with water but it was a bit softer under the file than I liked so I tried brine last Sunday and it came out nicely! The sample piece was the end with the nail puller and when forging it down it just became a "fish knife" with the nail puller being the flukes that are the tang---I didn't harden the flukes as they had been left rough ground. It's self hilted with the flukes resting in your palm and thumb and forefinger in indents right before the blade starts---looks like it would make a skinner with a curved blade. May be several reasons you had trouble: too hot when you quenched it, too thin when you quenched it, rough finishing marks that can propagate a crack or as you suspect wrong quenchant for that alloy. Spark test it to get an idea of the carbon content and compare it to a set of known standards, (1018, HC RR Spike~1030, file--1095, etc.). Very unlikely to be an air hardening steel---why pay $$$ for a piece of steel that needs to be tough but will only sell for $; but spark testing will tell you. Also as a used piece it may have suffered damage---why I saved the nail puller and curve for the test piece---most likely to have been stressed or hammered on. Thanks for that info. Yeah I went to work on another knife today, and my teacher said that when a crow bar is heat treated, you don't have to get it that hot at all. Only like 1400 degrees or soemthing. Hey I've got a question for you. Are you of Irish descent? Becuase my last name is Powers too, and my great grandfather was born in Ireland. It's funny my middle name is Thomas too! Man that's weird. Quote Link to comment Share on other sites More sharing options...
gypsy Posted March 30, 2009 Share Posted March 30, 2009 Most old American made pry & digging bars are 4130 in the post WWII era, pre WWII they are usually 1045-1065. As with many used steels I agree with "normalize, normalize, normalize!" & after hardening "temper, temper, temper!" also I learned the hard way with old jackhammer bits (s5 steel) to hammer used alloy steel only in the high forging range & also to stress test every blade made from old tools as pre-existing micro-fractures may exist that you can't see but will cause a blade to fail. any time I use used steel for blades now I lock it in a vice after heat treat, put a cheater bar on it & give it a flex in a quiet shop listening carefully for the tell-tale little crackling noises that shouldn't be there. its worth the time & effort to not have a blade come back from a customer broken. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted March 31, 2009 Share Posted March 31, 2009 High forging range will turn H-13 into cottage cheese! Every alloy has it's own preferred range. Well I read somewhere that 40% of County Waterford used to have the last name Powers or Power. So yes I am Irish on my father's side; add a couple more greats to get back to when we came over though; I used to be president of an Irish Living History group in centrtal Ohio till I moved far away for a job. Funny my middle name is Thomas too; I don't use my first name. Quote Link to comment Share on other sites More sharing options...
SRT02 Posted April 3, 2009 Share Posted April 3, 2009 Thermal cycling works good, I do it every time I make a new knife. Quote Link to comment Share on other sites More sharing options...
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