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Post by stuber2 on Nov 8, 2015 20:30:20 GMT
Hi, I need some advice. I bought a couple of blades from Albion's recent moat sale, and one of them has a slight warp to the blade, probably from heat treating. Its slight enough that when you hold the blade flat, so that the tip would point up, it actually straightens out. I would say its about a 1 to 3 mm warp. My question is, should I attempt to fix or can it be used as is? I know spring steel can be hard to bend, and I don't want to break it.
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Post by Lukas MG (chenessfan) on Nov 8, 2015 21:02:56 GMT
You can of course use it as is, it has no functional effect.
You can also straighten it. But please don't bend it over your knee until it eventually straightens out. Doing this "cold" weakens the steel. This is how I do it:
You need: Soft wood/metal brackets in a vice, small blow-torch, high grit sandpaper and a bowl of water (and the sword)
GENTLY heat the area of the bend to straw yellow (about 180°C), pay special care to the edges, being thinner they can heat up real quick. Then quickly insert in vice (jaws slightly open so you can insert the blade easily, but close enough so you can precisely flex the blade at the right spot) and flex in opposite direction (it takes some experience and feel for the steel, usually one has to over-flex a bit, just straight isn't enough). Immediately take out, check and cool in water. If straight, sand of the color and reheat again to straw for stress release. If still bent, sand, reheat and repeat process.
This process is a bit tricky and takes some courage because you're taking a heat source to the blade which CAN ruin the heat treat if you go too far. However, done properly it is the best way because it's the least stressful for the blade. Working under a bright light source helps when judging the color
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Post by stuber2 on Nov 8, 2015 21:42:13 GMT
Ok, thanks, I may just try that, sounds like a good method. Although if I can still do some back yard cutting with it as is, I may leave well enough alone. But I will definitely try that method if I do decide to try to fix it. Would a propane torch work or would I need something hotter?
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Post by DigsFossils-n-Knives on Nov 8, 2015 22:12:47 GMT
I would recommend this over heating the blade if you never heated a blade before:
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Post by DigsFossils-n-Knives on Nov 8, 2015 22:15:01 GMT
Shawn Hatcher method
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Post by DigsFossils-n-Knives on Nov 8, 2015 22:17:37 GMT
How I would do it (not my vids)
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Post by stuber2 on Nov 8, 2015 22:43:00 GMT
Thanks for the videos. Although at this point I'm leaning towards leaving it as is, I figure a slightly warped blade with good heat treat is better than a weakened or possibly broken blade if I do something wrong. My main concern was if I could use it with the slight warp, and it sounds like I can.
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Post by Brendan Olszowy on Nov 9, 2015 5:02:21 GMT
Ditto Chennessfan's advice. Only thing I'll add is to pull the gas torch away for 4 or 5 seconds intermittently, and more often as you approach your desired colour. This is because the heat oxide needs oxygen to take place. Under gas it won't colour correctly to indicate your heat. It's pretty safe if you keep your heat focussed on the thickest part of the blade and away from the edge. You can go twice that hot and still have fine temper. I have to do this to every blade I make, but usually immediately after pulling it from the temper, while it's still hot. Often in several spots. Most I do by hand with layers of leather to protect my hands. It's mainly if it's set at a ricasso or forte very close to the tang I'll used the vice as it offers extra strength I can't get by hand. There totally is a feel to it you get after doing a few hundred of them, a knack to getting it to end up straight. This is why I don't promote amateur flex testing.
Though it won't hurt you too much to leave it either. Swords don't naturally want to take the computer precise shapes some modern consumers expect of them.
Have you tried just some gentle flexing in the opposite direction, just cold - to say 15 degrees or so? That may sort it.
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Post by Lukas MG (chenessfan) on Nov 9, 2015 7:49:58 GMT
Only thing I'll add is to pull the gas torch away for 4 or 5 seconds intermittently, and more often as you approach your desired colour. This is because the heat oxide needs oxygen to take place. Under gas it won't colour correctly to indicate your heat. Very good point, forgot to add that. And yeah, agree with the rest also. Blades never want to be straight, you have to make them so and it usually takes a good deal of convincing.
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