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blade curve on w2 with hamon?


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Thinkin about going for a sword with a hamon, made from w2. Was wondering how much blade shape change I could expect? I know katanas get their curve from the differential heat treat, but tamahagane isn't w2, so I don't know the difference in behaviors. Let me know if I'm a crazy person or not

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A lot will depend on the cross-section.  A single edged blade will curve when quenched, the more strongly wedge-shaped the more the curve.  And the rule about water making it curve up and oil making it nosedive is true.  With the exception of the way Jesus Hernandez figured out how to get positive curvature in oil, pinned down in the metallurgy subforum.

This holds true for most steels, it's just a stronger effect the more shallow-hardening the steel.  Tamahagane is very shallow-hardening, so is W-2.  The curve will be similar, but since W-2 tends to be higher in carbon it is less likely to survive a water quench.

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So basically if I quench in oil I want to forge in a bit of extra curve? 

Also, how much movement should I expect? I was thinking something about 30" overall, with a fair bit of distance between blade and spine (leaning towards scimitar shape at the moment). So over 30", would the tip shift by like 1/4" off center, or more like a couple inches? 

Also also, how dangerous is the water quench? Is it worth risking water for the positive curve, or should I stick with oil and try to balance out the loss of curve?

This is my first attempt at a (short) sword, so any and all info would be greatly appreciated

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It depends entirely on the cross-section of the blade and how far down you add the clay.  A long thin wedge like a full flat grind will move a bit more than a Japanese-style section.  See https://www.bladesmithsforum.com/index.php?/topic/35243-wip-langes-messer/&tab=comments#comment-342073

 

for an example.  He did not clay the blade and got about two inches of negative sori.  Check out his Messer 2.0 for how much precurve he forged in to account for round two.

Water will kill W2 almost every time.  Expect a 10% success rate when starting out.  Even with Aldo's 1075, which is closer to tamahagane, expect only a 75% success rate in water.

I'd use hot canola and forge in about two more inches of curve than you want.

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Started the profile forging. This is gonna take a lot longer than I thoughy it would. Gonna look great tho. I'll post pics n such once it's ready. Thanks Alan, you're a hero

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