I posted a thread yesterday on straightening a blade and got some good replies. I should have been more specific in my choice of words, the sword i did has to much of a curve in it, and i was wondering if anybody knew of a way to take some of the curve out without ruining the hamon heating it up. like maybe at a low heat.
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to much curviture
- Thread starter neil g
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Stacy E. Apelt - Bladesmith
ilmarinen - MODERATOR
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If the problem is too much sori,there is no way to reverse it that won't ruin the sword. The problem often comes from the maker trying to forge in the sori. If the blade is straight (sometimes even a little recurved) then the sori will lift to a gentle curve. If you start with a positive curve (forged in sori),you will get a big saber type curve after the sori forms.The sori is a bit of a guess (unless you have made hundreds or thousands of swords) but most makers start with a straight sword.Look at a book on katana - there is quite a bit of variation in sori.Even the old smiths were shooting in the dark,often.
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- Aug 4, 2006
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heat to 400 F and pound on the shinogi with a hammer. It's the only way I know to take the curve out. You're expanding the metal in the back of the blade which will cause it to curve in the opposite direction, just like when you forge an edge.
What kind of steel did you use? How high up is the hamon? Is there any muneyaki?
Next time you quench a blade curve the front 1/4 down about 3/8 of an inch and bend the tang up about the same (3/8 of an inch measured the same way you'd measure sori). Steel type, clay placement and thickness has a major role, too, as does quenchant and whether you're doing an interupted quench.
What kind of steel did you use? How high up is the hamon? Is there any muneyaki?
Next time you quench a blade curve the front 1/4 down about 3/8 of an inch and bend the tang up about the same (3/8 of an inch measured the same way you'd measure sori). Steel type, clay placement and thickness has a major role, too, as does quenchant and whether you're doing an interupted quench.
Thanx for the reply Joe i'm actually a big fan of your work. i was able to take some curviture out of the blade heating it up to about 600`F and putting it in a padded vice. After i was finished i checked the cutting edge with a file and it skated across it easily. The blade is made from 1045 carbon steel, the only reason i chose this steel was to see the kind of blade the gunters super quench would make and to see what the hamon turns out like when i'm done polishing it. I'm going to use the hybrid polish method, then etch with ferric chloride. The hamon takes up about 30 percent of the cutting edge. Any further comments would be appreciated. I'll post pics when i'm done. If their good.