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Old 14th July 2017, 10:42 PM   #26
Philip
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Join Date: Dec 2004
Location: California
Posts: 1,036
Default straightening blades

Quote:
Originally Posted by Will M
If the blade is not cracked it could be straightened and the scabbard reshaped, nothing is impossible.
Yes, but emphasis should be put on the word "could", with the unspoken caveat that nothing in life is guaranteed except death and taxes. As a restorer, I have encountered blades bent in varying degrees, in different locations along their length, and in odd ways as well (twisted, and even distorted edge-to-back rather than side-to-side). Most cases do turn out well, fortunately. On the more severe ones I consult with colleagues who are sword MAKERS, such as Vincent Evans (pattern welding and differential heat treat), and Ric Furrer (he makes wootz in the traditional manner).

Blades bent at the forte CAN be less risky than those distorted nearer the tip. I once fixed a katana blade that was tweaked about 5 degrees from true just ahead of the habaki, and managed to do it "cold". Like most Far Eastern blades, the steel is hard only along the edge, and in many cases, the "hamon" or crystallized zone is narrower at the root. Fortunately, this made the job quite doable. I've also straightened a few Moro swords that were bent in the same region, on those blades the hardening really doesn't start until a few inches further towards the business end, so the metal is less brittle there.

Wootz can be another matter. The material has a higher carbon content than the range for "tool steels" which most sword blades fall into, and is inherently more brittle as a result. I am surprised that this shamshir could have been bent that much without snapping outright. But my years of polishing these blades has shown that some of them ARE differentially hardened (after a full polish and an etch, a "hamon" does appear along the edge on many Indian and Persian wootz blades). This crystalline edge zone, on Islamic sabers, tends to begin somewhat ahead of the hilt. And when skilfully etched, you can see at the forte a gradation in steel color corresponding to oblique bands or zones, which tell me that the smith treated the metal in stages to optimize the degree of hardness and resiliency as required in different areas. This is confirmed empirically when polishing, the forte area does not "resist" the abrasive action of the stone nearly as much as the fully hardened cutting edge. In such case, the steel at the forte would be more ductile and thus pose less of a risk of breakage than with one of those that was uniformly heat treated so that it it is just hard (therefore, likely to be brittle) throughout its length.

In the case of a severe bend or with wootz that is quenched to uniform hardness, the risk lies with whether or not the steel has been stressed sufficiently to have created internal faults that will develop into a real problem (hairline crack, or a crack spreading to complete breakage) when the metal is moved back the other way. This is where consultation with my swordsmith buddies, and a frank exposition of the risks with the customer, are in order before formulating a POA.
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