Blade Straightening

tom hyle · 30th January 2005, 04:12 PM

This is probably a spring-tempered blade. You may be in luck if the bend is at a soft forte, but otherwise may be very hard to straighted. If you use a hammer, use a hammer and anvil of softer material than the blade; copper, lead, and rubber all come recommended. You're not going to get any results with a spring-tempered blade unless you go considerably past the results you want and let it come "back"; this is tricky at best, in terms of both angle and placement (avoiding the "s"). Locallizing the bend can involve clamping one straight part in a vice with padded, preferably round-topped, jaws, and bending it by hand or with another clamp. This is the method most likely to stress or crack your blade (though Justin is quite correct that decent old swords very rarely break). Alternately, you can use 3 blocks in a vice, so one pushes the bend "down" between the other two. This method can give great pecision on softer-than-spring blades. Many old spring-tempered blades are at a soft-spring temper; springy, but a little softer than a true spring temper, and can be bent. True spring tempered blades commonly get bent during hardening, when the steel crystals change size. Such bends, called "casts", are usually gradual. Convincing speculation is that locallized bends arise when blades are thrust through bone, and get tightly "kinked" over it in the death-throes or withdrawal (this is an especially convinving scenario for cavalry swords), or possibly that the strain of a thrust-flex, perhaps on encountering armour or bone, can be too instantaneous for the springiness to fully absorb. Such acquired bends, occasionally intentionally formed by or for swordsmen, as well, are called "setts".
There's a booklet, usually available on the internet, that claims to inform as to straightening swords and gun barrels. I haven't read it; just thought I'd mention it.

30th January 2005, 04:12 PM	#7
tom hyle Member Join Date: Dec 2004 Location: Houston, TX, USA Posts: 1,254	This is probably a spring-tempered blade. You may be in luck if the bend is at a soft forte, but otherwise may be very hard to straighted. If you use a hammer, use a hammer and anvil of softer material than the blade; copper, lead, and rubber all come recommended. You're not going to get any results with a spring-tempered blade unless you go considerably past the results you want and let it come "back"; this is tricky at best, in terms of both angle and placement (avoiding the "s"). Locallizing the bend can involve clamping one straight part in a vice with padded, preferably round-topped, jaws, and bending it by hand or with another clamp. This is the method most likely to stress or crack your blade (though Justin is quite correct that decent old swords very rarely break). Alternately, you can use 3 blocks in a vice, so one pushes the bend "down" between the other two. This method can give great pecision on softer-than-spring blades. Many old spring-tempered blades are at a soft-spring temper; springy, but a little softer than a true spring temper, and can be bent. True spring tempered blades commonly get bent during hardening, when the steel crystals change size. Such bends, called "casts", are usually gradual. Convincing speculation is that locallized bends arise when blades are thrust through bone, and get tightly "kinked" over it in the death-throes or withdrawal (this is an especially convinving scenario for cavalry swords), or possibly that the strain of a thrust-flex, perhaps on encountering armour or bone, can be too instantaneous for the springiness to fully absorb. Such acquired bends, occasionally intentionally formed by or for swordsmen, as well, are called "setts". There's a booklet, usually available on the internet, that claims to inform as to straightening swords and gun barrels. I haven't read it; just thought I'd mention it.