char Posted November 11, 2008 Share Posted November 11, 2008 I've made a couple of kitchen knives for the relatives (if they turn out ok) this holiday and I've just edge quenched them. I was washing them up and I realized that I didnt know if I was supposed to temper them the way I normally would. One of them also developed a pretty good curve that it didnt have before, can I just straighten as I would any other? Thanks gentlemen Quote Link to comment Share on other sites More sharing options...
Robert Mayo Posted November 11, 2008 Share Posted November 11, 2008 Char First yes any carbon steel that is hardened needs to be tempered to reduce the stress in the steel. It is hard to tell you at what temp without knowing the type of steel you used. As far as the curve is it a sideways curve? If so the best time to staighten a blade is straight out of the quench when it is still above 400 degrees. You can try and straighten it after the temper as well put your blade in the oven at 400 degrees for 2 hours then with heavy gloves take it out and try and straighten it. Bob Quote Link to comment Share on other sites More sharing options...
char Posted November 11, 2008 Author Share Posted November 11, 2008 Sounds good thanks alot. I dont know what kind of steel it is, I made them from an old lawn mower blade that my neighbor gave me years ago when I started grinding knives. So temper it is Quote Link to comment Share on other sites More sharing options...
NateDJ Posted November 12, 2008 Share Posted November 12, 2008 I have always been told that lawnmower blades are 5160 steel. They do make very good knives! Quote Link to comment Share on other sites More sharing options...
Steve Sells Posted November 12, 2008 Share Posted November 12, 2008 just goes to show ya never know what ya got with recycled metals, My lawn mower blades have turned out to be 1080 Quote Link to comment Share on other sites More sharing options...
NateDJ Posted November 12, 2008 Share Posted November 12, 2008 How can you check to be sure? I have NO luck spark testing. Quote Link to comment Share on other sites More sharing options...
Woody Posted November 12, 2008 Share Posted November 12, 2008 My junkyard steel list shows mower boades to be 1085. Now days you never know though. I have heard, but have no way of verifying, that they now make them out of lower carbon steel for liability reasons. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted November 13, 2008 Share Posted November 13, 2008 (edited) We recently tried commercial lawn mower blades tossed by the University Grounds crew: Would *not* harden to brittle in oil or water; pretty useless for us. Junkyard steel lists are not known for their accuracy as you will learn the first time you try to harden a microalloyed stress hardened leaf spring... Edited November 13, 2008 by ThomasPowers Quote Link to comment Share on other sites More sharing options...
Steve Sells Posted November 13, 2008 Share Posted November 13, 2008 there are only 2 ways to know for sure, 1) ask manufacturer, and that is assuming they never ran out of stock, and had to use a substitute, to make quota. 2) Lab testing, not cheap, ($200 a test or more) but my old teacher was a Gov't test engineer. He took them to work for testing himself. Its much safer, and easier to buy new steels when we need to know what it is. Quote Link to comment Share on other sites More sharing options...
Robert Mayo Posted November 13, 2008 Share Posted November 13, 2008 If you have a university close they will usualy test a sample for you. Bob Quote Link to comment Share on other sites More sharing options...
Sam Salvati Posted November 14, 2008 Share Posted November 14, 2008 there are only 2 ways to know for sure, 1) ask manufacturer, and that is assuming they never ran out of stock, and had to use a substitute, to make quota. 2) Lab testing, not cheap, ($200 a test or more) but my old teacher was a Gov't test engineer. He took them to work for testing himself. Its much safer, and easier to buy new steels when we need to know what it is. Fastenal offers spectral analysis of steel samples for alloys and carbon content for MUCh cheaper than that, ask your local Fastenal branch about it. Quote Link to comment Share on other sites More sharing options...
Iron City Posted November 14, 2008 Share Posted November 14, 2008 Fastenal offers spectral analysis of steel samples for alloys and carbon content for MUCh cheaper than that, ask your local Fastenal branch about it.Modern Industries will do Analysis for $50.00 Quote Link to comment Share on other sites More sharing options...
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