Heat Treating Knives, Blades etc

Tonight I attepted to harden a 15" 5160 blade in a coal forge that wasn't quite big enough. I moved the blade slowly to distribute the heat. But I failed to achieve uniform heat across the blade. (some parts started to burn, while others still had a "shadow" in the orange. Quenched it in peanut oil, and the file test releaved uneven hardening. So I desire to try this again, if I can get away with it. Problem is: there's a serious amount of carburization on the surface, that will be a **** to clean up. (picture) So the two questions are: can I repeat the quenching process and still end up with a hard edge, and is there a way to minize the carburization in the fut…

I am new to blacksmithing and have a question. Let say u want to make a knife for example. So u use 1050 and harden it but do not temper and it reaches a certain hardness. Now u go and make another knife from 1095, harden it and then temper it so it reaches the hardness of the 1050 knife. Will they perform the same? or will one perform better then the other? If so could someone please explain how and why.

I believe the critical temperature is 727 degrees Celsius, if I'm not mistaken. If one has an optical pyrometer (which I don't), one could measure the temperature from a safe distance. Also, a bit off the subject, the Verhoeven mentioned is the same one that validated the re-discovery of true Damascus steel techniques by Alfred Pendray. I read his papers on the studies and they were all very informative - recommend them to anyone who has the time/capabilities/equipment to attempt making true Damascus items vs. normal pattern-welded items.

I have a document in Adobe titled "Metallurgy of Steel for Bladesmiths & Others who Heat Treat and Forge Steel", 200 + pages, By John D. Verhoeven Emeritus Professor, Iowa State University, March 2005. While it is extremely technical in nature, there are summaries of all the important points at the end of each chapter that are easy to understand and very clear and concise. It will help dispell some of the myths and alchemy associated with Knifemaking in particular and forging and heat treating steel in general. Also have an Adobe document "Experiments on Knife Sharpening", 55 + pages, September 2004 by the same author. If anyone is interested, please email me and…

I quenched an O-1 blade in peanut oil and noticed a strange pattern on the surface of the blade. The pattern looks like veins that are slightly raised on the surface. This was very difficult to photograph but I do have photos to share; however the site is giving me an error message with the picture upload at this time. Would anyone know what this means,and whether I somehow ruined the blade? (My first time dealing with O-1). Thanks for any insight you can provide.

Folks: what is the general consensus about trying to harden the edge of mid-size bladed (say 1/8 inch wide, 4 inches long) with a regular plummer's torch? Some of these torches develop more heat than others, but would it be a waste even trying? (Before I purchase one for the purpose.) The steels will be 10660-1095, 5160, and O-1. Thanks!

While I was hunting to day I noticed the abundance of black walnut trees on the property and I was wondering if quenching in walnut oil gathered from squished hulls would do much. That stuff dosn't come off of anything and I was wondering if it would leave kind of a reverse hamon on the blade from an edge quench. anyone ever tried this?

I've been making some knives out of high carbon steel and hardening them once and they keep a very nice edge for a long time and take a lot of abuse, my question is why i've heard to always harden three to five times? When i did my blade tip cracked on the top! I have let my blade cool completely, in the oil. cool enough to handle bare-handed. This blade was also annealed over night in ashes, before i started the hardening process.:confused:

Folks: a few related questions: How many of you use tool wrap for heat treating? I imagine this is just for those who heat with a controlled furnace, since you can't see through the wrap to judge the blade's temp. What's the advantage of wrapping a blade in stainless steel foil? (I'm guessing that even heavy gauge aluminum foil would burn up at typical heat treating temps, correct?) Thanks for any guidance here.

i'm almost ready to temper a blade i'm working on and i was going to clay temper it, but what i need to know are two things... 1) do i normalize the blade before clay tempering 2) should i polish it before clay tempering i'm new at this obviously from my other threads and i would like some advice. when i'm done with the piece i'll upload a pic.

Folks: I see the orange coals burning brightly at the base of my woodburning fireplace, which gets plenty of air from the chimney draw, and have to wonder: is there any solid reason I couldn't heat treat a knife in there? Is it just not enough heat compared to a coal forge with hand-cranked air supply or a gas forge? Thanks

Hi, new here and a rank ametuer. I have made scant few knives but do have a little backyard savvy on welding ect. Recently I have decided to make some knives in the spirit of the old trade knives and buffalo skinners. My first two were from files. One is finished but I didn't temper it before I handled it. I used ironwood for the handles and now I am wondering if I might be able to draw that edge out a little without ruining the handle. Any suggestions? I also have another file blade hammered out and have not put a handle on so it should be easier. Oh, and I also have a couple Ulus I made many years ago from skilsaw blades and they wont take an edge either, didn't treat …

Greetings! Wow, been lurking too much! There are soo many new members! Anyway, I had a quick question: How would you HT a sort of Rambo IV machete? I am making one because I live in Brasil and am surrounded by junlge, so I need a good chopping tool. I am going to forge it from a leaf spring, darn good steel. I want to it to be quite sharp, but with good edge holding properties comes the risk of cracking. Should I soften the spine a bit? Maybe to a dark blue? The edge itself would soak at 170 to 180 C. Furthermore, how should the blade geometry look? Do I forge it high-flat with a small secondary bevel? Or do a sort of scandi/convex grind? I was thinking somewhere a…

Would this work? 1" thick inswool/kaowool coated with satanite refractory all around the inside, burner port at one end, with a fire brick in fornt of the flame to disperse/baffle the heat, with the blades never extending over the firebrick and flame itself. ID is 10 inches, would this be suitable for heating blades nice and even to the proper temperature? I would use just the PSI valve to control the heat with a thermocouple to measure how hot inside it is and control it from there. I know it wouldn't be as good as salts or an electric oven or kiln, a bit oxidysing, maybe a bit uneven heat but much more ideal than using just the forge.

Neat site, I'm a custom knife maker that was doing pretty good before Katrina, took 4 ft of salt water in my shop. So I moved built a new house and shop, just getting started again. The edge tempering of the Japanese always interested me. I'd like to know the basic process so I can experiment with high carbon steel, probably 1095. Thanks

Hi, I have a problem. I tried regular clay, from the dirt. then raiku clay,which is probably a broad general term. then mixtures of charcoal, ash, and clay. and now a mixture of charcoal, ash, clay, and borax. I can't get the dried clay to stay on the steel, it "pops" off. I have a propane forge. should I try with charcoal. Is it the wrong mixture? should I just try to find a tempering clay. what am I doing wrong?

I've been hobby forging for a while with a very rudimentary set up. Recently I've started to take heat treating seriously and am having problems. I made two knives both out of pry bar steel. I wanted to put them through their paces, test them out to make sure they were good, and of course, they both broke. The first was quenched in warm brine, the second in motor oil. They were both tempered in an oven and then differentially tempered by heating the spine and tang with a torch while dipping the edge in water. When the first blade broke I assumed it was just a poor tempering job, so when I tempered the 2nd blade I baked it at 350 for 2 hours. After seeing no colou…

A customer wants a home made knife, heat treated its made from a Lg circular lumber mill blade 1/4 tc . MY ? is what kind of steel this mite be & how do I heat treat it ? knife is 1/4" x 16" bowie style THANKS Steve @ :confused: Steve's Welding

I notice alot of smiths prefer transmisson oil is it pretty good,as oils go. Thanks in Advance

Hey, I just signed up not 10 minutes ago. I was wondering, could one buy a P.A.C. (piece of crap) sword on ebay and temper it? I wouldn't be very good metal, and you probably wouldn't be able to take the furniture off to temper the whole thing. But at least it would hold an edge. Right?

Folks: I'm still at an experimental stage with kifemaking (having only completed about a dozen to date) and would like to know your prefered methods for edge hardening. I've ruined about as many as I made, so I'm still a little trigger shy with the quench method and medium. What seems to work best for you? I've quenched medium to high carbon steel in different oils with better luck (i.e. less destruction) than in water, but with an apparent tradeoff in edge hardness. My goal is to achieve a very soft (non-brittle) knife spine together with hard edge. My attempt at edge-quenching in water destroyed the blade. Is it better to quench the entire blade and then temper …

I am in the middle of making my first knife out of a rail road spike and am about to heat treat the blade. after that is done I am going to hand sand the knife until I reach 1200 grit when I have nothing finer. But to me that is not shiny enough. I would like to buff it but I am afraid that if I get it the blade too hot, I might ruin the the heat treatment. Is this possible?

Ok, first and foremost you should probably know that I'm working with leaf-springs as my metal, and I have a small gas forge. I'm making knives, daggers, and short swords. Question #1: Where do I get oil for quenching? I know using water as a quenching medium is bad for the steel, so I should use olive/canola oil right?So where should I look to get oil in large quantites, and how much would it cost? Question #2: I know that tempering something well requires much experience and trial and error. What guidelines are there that I should use while attempting to temper the steel as far as color, and time in the tank go? Question #3: You need to harden the steel before …

What kind of quench tanks are best for knife making. I thought I remember seeing some made out of 3 tubing which I happen to have. I have probably enough that I could make several small tanks with different quenchants. Or are troughs of some sort or another better? I'm thinking something that I could put a lid on would be nice to keep contaminents out of it.

Greetings Everyone, This is a bowie of 1095 with walnut handle and clay ht. 6.5" blade, 1/8" thick at ricasso, with slight taper I am happy about this one, it is the first time I did the differential temper thing with clay. It came out better than I expected. The clay I used came from a little "home cooking." (I made the mixture myself) The clay came from unscented, bargain basement kitty litter. 1 part kitty litter 1 part crushed brick 1 part wood as and sugar (yep - sugar, mostly carbon, sticky when wet or melted, actually grows when burned) Seeing the diff heat treat reminded me of how magical steel really is. I have one major question: Will someon…