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The Newbies Arena Are you new to knife making? Here is all the help you will need. |
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#1
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1st knife - 01 steel HT and warping question
Hi,
I just HT my first knife and am concerned I might have over heated it. This is the first time using my homemade forge and after two minutes of the blade being in, it was bright orange (this is 01 steel). It was not magnetic and I immediately quenched it. I am tempering it now, but I am not sure if I might have over heated the knife. Also, I noticed that the knife is no longer flat. If looking at the spine of the knife, the blade turns slightly to the right. Did I overheat the knife? And if so, what can I do to fix it and the warping? Thanks in advance, Shawn |
#2
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Bright Orange is perfect for only 2 minutes. Next time try to work it back and forth and hold for 5 minutes at bright orange, but not yellowish. Temper at 400 degrees for 2 hours, then cool to room temp. Now take a metal shim, a penny or quarter and put it under the bend and clamp to an angle iron or some very thick metal and quench at 450 for 2 hours. Most of the warp should be gone. If there is still some you can clamp it on the ends and putting a shim in the middle slowly bend it straight. Now if you do not have something to clamp it too during temper you can bend it gently in a vise and I hate to tell you that if that is all you have, but if you are careful you can bend it in the vise, but do not try to go past the warp by more than 10% of the bend. Then maybe you can grind the little bit of warp out.
You didn't finish grinding it before heat treat did you? Last edited by jimmontg; 11-01-2016 at 07:05 PM. |
#3
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Quote:
The HT really shocked me. This was my first time and it is a little intimidating to be honest. I was thinking it should take closer to 5 to 10 minutes to get it at the right temp, so when I removed it and saw it was orange I was definitely concerned! Maybe I should cut back on the air going into the coal fire... No, I didn't move the knife back and forth. I just put it into the hot spot and left it. I also didn't swirl the knife in the cooking oil. I dunked it, waited for the flame to go out and then a few moments after I moved it in a up and down motion taking it part of the way out of the oil. That could have been my problem. Thank you SO much for the suggestion! Shawn |
#4
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Actually, you probably did overheat the knife. Colors are subjective and 'bright orange' for you isn't the same as it would be for me. The magnet is the way to tell but from your description I'd guess you only noticed it was non-mag long after it passed that point. The trick is to catch it as just as it reaches that point, then let it rise another 150 degrees or so and quench.
The good news is that O1 will probably make a decent blade no matter how badly your HT worked out. But, it makes a terrific blade if you get it right but that won't happen in a forge, for that you need a furnace. Next time, get some 1084 and you'll have a good start on learning to heat treat. I know this next part will probably fall on deaf ears but I'll say it anyway: you need to test that blade very hard and then break it to see the grain. That means don't spend a year polishing it and making a fancy handle, just do it rough and then test. If you won't do that you'll never know just how good or how bad the heat treat was so if you made a mistake you'll make it again on the next one .... |
#5
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Quote:
Shawn |
#6
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My experience with O1 Ray is with a kiln at 1475 it's a fair orange color and bright orange isn't going to be too much, the problem is only two minutes and how did he quench it. If he twirled the blade around it would warp and if he ground too much off it's going to be very prone to warp. Yes bright orange is a little too hot, but at least he didn't say yellowish orange.
LOL |
#7
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This is my first time and I am more interested in learning and enjoying the process rather than making a great knife. I would like to get there eventually though! Thanks. |
#8
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And if he's a little color blind or if he's under fluorescent lights or if if if....He's a newbie, he should be learning to use a magnet and preferably on something other than O1. Color is subjective, the magnet is not...
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#9
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What really shocked me was the time in the forge. I thought it would take longer than 2 minutes. I guess I need to turn the blower down next time. Shawn |
#10
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Didn't know you had a coal fired forge. If it didn't heat from both sides evenly could be another reason for warping, but if you had the blower going full bore that probably wasn't the problem. Two minutes is definitely quick to bright orange in the daylight. O1 is a tool steel and is best done in an oven where it can be held at the precise temp of 1475 for at a minimum of 5 minutes and I have recently found out that it can go to ten- fifteen for a greater mix of the chrome and tungsten with the carbon and mere 0.20% vanadium. It is more forgiving in some ways, but a 1080 steel might be better (and cheaper) way to learn to HT.
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#11
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Quote:
Shawn |
#12
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If you leave the O1 just sitting in the coal forge for 10 minutes it will almost certainly overheat unless you can somehow magically guarantee that the temp will sit solidly at 1475F. That's why we say that O1 cannot be properly heat treated in a forge. That won't stop you from making a serviceable knife but it won't be quite as good as it could be.
As for that true north stuff, I would put that in the same category as the old myth about edge packing... |
#13
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As Ray said, can't hold in a forge, I was talking about a heat treat oven with precise temperature controls and O1 comes out looking orange red under fluorescent lights, not bright orange. I was the HT guy at a machine shop and a fast heat may also be the reason for your knife warp now that I think about it. Another reason not to HT it in a forge, besides 1080 is much much cheaper and will make a good knife out of a forge.
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#14
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Would you suggest me reheating it more slowly and try to keep it at a red-orange for a longer period of time? If so, is there anything I should do first? I did temper it with a coin and clamps to remove the bend.
Thanks, Shawn |
#15
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No do not reheat it.
Have you tried to run a file across the edge and if so how much did it seem to bite. Run the file away from the edge not into it. If it barely bites into it you are on the right track. Note a file should bite into it, but not easily, you should now have to put some pressure on it to file the edge. If it files it easily you tempered it too long or it didn't harden up right with the overheat. You can make it too hot. A lot of the carbon steels will have a sweet spot and it's between 1425 to 1480 and the higher the carbon the higher the austenitizing or hardening temp. As I said before O1 is 1475, but you have some flexibility if using a forge. Your bright orange in sunlight would be up near 1550 (max for O1) to 1650, was it yellowish?
Next after you grind it down and put an edge on it where you think you want it is the brass rod test, If it chips then you have some brittle steel and need to temper it back some more and if it bends and doesn't come back it's too soft, but the file will tell you that. Those are the two best tests you can do right away and if you really want to see what happened you would then put it through its paces and start carving shavings of preferably hardwoods or if you have some old thick rope see how many cuts you can do before it dulls up. Try to find a video on youtube On the Knife Brass Rod Test to show you how it's done.Here's one. https://www.youtube.com/watch?v=woP1tqF-dsg Now I do not brass rod test my knives as I don't think it's as important as the hardness that is best for the steel I'm using. I have hardness files and can test my hardness (pretty much) and if it's where I think it should be I do the cutting tests, if it's too hard whittling dymondwood will crack the edge. I know my steels that I use and how they should be. Air quench steels I send to a professional heat treating company. I sometimes used to use the forge at the college down the hill in trade for teaching TIG welding, but they haven't let me use it the last few blacksmithing or knife forging classes as the new welding teacher doesn't want me "screwing" his students up with my 40 years of welding experience and metallurgy classes. So they go out not knowing how to counter warp weld or even how to weld a 90 degree angle without having to beat it back with a big rubber mallet. Their syllabus doesn't teach somethings that experience could. But I'm not resentful! LOL I just have to buy Damon some propane and drive 60 miles and he'll let me use his forge after he tunes it up or something he said was wrong with it at the moment. He also tries to poison me with the hottest peppers in the world he grows. He's also one of the best engravers and knife makers around too. |
Tags |
angle, back, blade, degrees, first knife, first time, flat, forge, grind, grinding, heat, heat treat, homemade, hot, iron, knife, lights, metal, newbie, pen, quenched, steel, temper, vise, warping |
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