Excalibuitar Posted June 30, 2011 Share Posted June 30, 2011 Didn't know whether to post this in Knife making or Heat Treating.. Figured I'd keep it here since HT is an essential part of making knives. Anyway, I am new to the whole weapon making thing. I started on my first 2 knives yesterday and got them both ground down relatively nicely for never having used an angle grinder before. One is a dagger with small tang and the other a full tang work knife, both made from the same coil spring from a mid 60's Ford Falcon. I heated to non-magnetic, and quenched immediately in room temperature vegetable oil. After this first one, I remembered hearing for 5160 (which is my best guess on the coils..) it should have been heated first.. So, before quenching the 2nd knife I heated the oil with a hot piece of square stock. Anyway, they both came out with white splotches all over. I was going to stick em in the oven for 2 hours at 375 and then turn it off and let them cool to room temperature in there.. But I figure I'll play it safe® and get some opinions on here. I assume I screwed them up... Also worth mentioning, I did not anneal them at any time in the process as they forged easily without cracking and I was under the impression it wasn't necessary.. First post here, but I've been reading and drooling over knives for a few days now. Thanks in advance for any help.. Brandon Quote Link to comment Share on other sites More sharing options...
Steve Sells Posted June 30, 2011 Share Posted June 30, 2011 what does forging with out cracking have to do with not normalizing? Keep reading, there is a lot more to this than you seem to understand. For one you are lucky it didnt crack from the row of gouges you left from grinding in the blade edge, those are all stress risers. The white spots could be from the oil, read more, and keep trying, and then read more :) Quote Link to comment Share on other sites More sharing options...
pkrankow Posted June 30, 2011 Share Posted June 30, 2011 so...they have not been tempered yet? That means they are brittle (unless they didn't harden for some reason) I would bake them all the same then move on to finishing or figuring. If they are untempered they may shatter like glass. Phil Quote Link to comment Share on other sites More sharing options...
jeremy k Posted June 30, 2011 Share Posted June 30, 2011 They may be burn marks during the forging process? Hard to say with out more info on type of forge/fuel etc, etc. or what actually you did during the process. Quote Link to comment Share on other sites More sharing options...
Excalibuitar Posted June 30, 2011 Author Share Posted June 30, 2011 I use a coal forge. Anyway, they looked a lot nicer, and were all cleaned up and smooth before the heat and quench. The quench seemed to create a lot of the 'pits' and stuff you can see up close.. Not sure. As for the annealing, I have read that it is used to soften metal to make it workable. Didn't seem necessary, especially after reading the techniques of others, many of which not including any annealing. It's pretty confusing to try and make sense of what to do when everyone does things differently. I suppose I'll stick em in the oven and see what happens.. Trying to clean them up first with the grinder.. Quote Link to comment Share on other sites More sharing options...
felix24 Posted June 30, 2011 Share Posted June 30, 2011 Welcome to the forum my man , I would suggest you normalise the blades before quenching them in oil next time. Normalising releases stresses from the steel, which may cause the blades to crack or warp when quenching, and evens out the structure of the steel (don't quote me on that ), making a better quality blade. This is done by heating them to non-magnetic and letting them cool naturally to room temperature. Do this three times. After you've quenched the blades, you can test if they are hard by trying to scratch them with a file. If they are hard, the file will just slide over the surface. in this state, the blades are very brittle and will crack or shatter easily. I think grinding them while hard may be a bit stressful and cause them to crack. I'd say just carfully sand all the scale off them until you can see the shiny metal, don't worry if there is some pitting on the blades, and them temper them in your oven or with a blowtorch. After they are tempered you can sand off the pits and have your nice shiny blade back the way it was . Hope this helps and enjoy the knifemaking . Quote Link to comment Share on other sites More sharing options...
Excalibuitar Posted June 30, 2011 Author Share Posted June 30, 2011 Thanks Felix, very helpful. So to normalize, get them to non magnetic and remove from the coals? Or should I turn off the blower and let the fire die slowly with the knife inside, then air cool? B Quote Link to comment Share on other sites More sharing options...
son_of_bluegrass Posted June 30, 2011 Share Posted June 30, 2011 I suggest, before you get too far, you find a decent book on knife making and read that. I've got "The Complete Bladesmith" by Jim Hrisoulas and can recommend that one. I've seen others recommend "The $50 Knife Shop" I believe that is by Goddard. If you are going to make knives and use what you make, you'll want to do it right and reading with get you to right with a lot less frustration. You may be able to find these books in a library (or through inter-library loan) or in a used book store. If you haven't done so yet, read the stickies, there is a lot of good information there. ron Quote Link to comment Share on other sites More sharing options...
felix24 Posted June 30, 2011 Share Posted June 30, 2011 yeah. to normalise, heat them up to non magnetic, remove them from the fire and let them air cool. if you leave the blades in the fire as it slowly goes out, they will cool very slowly over a span of hours. they will then be annealed. in this state, the steel is very soft and can be worked with hand tools such as files, hack saw etc. the hardness of the steel depends on the speed at which it cools. i.e: annealed => cools very slowly and ends up soft. Normalised => cools faster and ends up tough, but not fully hard (you can use a grinder on it, but not hand tools most of the time). Hardened(quenched) => cools very fast and ends up very hard. In the hardened state the blade is essentially useless because it's too brittle for nearly every task. That's where tempering comes in. When you temper the blade, you are bothe relieving stress in the blade that was caused from hardening, and slightly softening the steel so that it becomes tougher and less brittle, but still hard enough to hold an edge. You can temper it to different degrees, which are shown on the blade as temper colours as the blade heats up. From coolest to hottest you roughly get the following colours: straw, gold, brown, purple, dark blue, light blue, grey. Straw being the hardest and grey being the softest. At dark or light blue the steel becomes springy. best of luck with it! Quote Link to comment Share on other sites More sharing options...
Steve Sells Posted June 30, 2011 Share Posted June 30, 2011 A basic set of guide lines is all at the top of this section, sticky posts, for dealing with this, so I don't have to keep repeating the same stuff.Link to... sticky info : http://www.iforgeiron.com/forum/56-knife-stickies-here/ Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.