"Ankerson. what about metalurgy? I mean, a modern Mercedes Benz truck spring has got to have qualities in it, that once expertly forged and differentially hardened, a 500 year old thousand times folded Katana does not? Where's firkin?"
Cripes, munk---You think I know everythin'????
Yes the qualities will differ, but will it be better and how to tell?
I can provide a few things that I've read or occur to me that maybe bear thinking about.
Somewhere, on the shop forum Ed Fowler described a knife he'd forged out of ,I think, 52100 steel, which as I understand it, is similar to 5160. He's spent a huge amount of time experimenting to see the effects of forging temperatures, repeated heat treatments, and the like. Lots of destructive testing. He produced a knife, that when held in a vice with rounded jaws could be bent 90 degrees, then 180 to the other side, MULTIPLE TIMES with no apparent damage. I think it was eleven times before he decided that was enough and not worth testing this knife to destruction. The edge didn't crack. It passed the rest of his tests.
The knife's properties were not due to the steel employed, but due to how this bladesmith changed the properties of the steel, which he obvously understands very well. Some steels are better for making swords and big knives than others, and some are clearly not suited. But what a smith or heat-treater does to the steel makes a difference, sometimes an immense difference.
It's pretty hard to interpret comparisons between old and new blades. Some things that confuse the issue:
1) Are any modern steels produced to be optimized for forging into a sword blade?? I'm in no position to know but I doubt it. Some steel is produced by hand in Japan, by traditional means, but that is an attempt to replicate the old ways. Most smiths choose from a collection of modern steels usually intended for other purposes or optimized for modern manufacturing techniques. Who knows what would happen if an effort was put into finding new steels for bladesmithing was comparable to that put into finding new steels for modern machining production?
2)Much of the old "recipes" for steels and the forging techniques that applied to them are lost, as they were trade secrets. Some claim that wootz has been "rediscovered", but how to know? Nobody's going to beat up priceless antiques and then cut off chunks for analysis. How representative are the remaining old blades of the time from which the came? Hard to say, but some of the best-preserved are likely to be exceptional examples of their time.
Once, swords were an important weapon, and a large portion of military spending or equivalent was spent on them and their production. Especially by those for whom one was a status symbol. Now things like aircraft carriers are what the money is spent on. Put the cost of a couple aircraft carriers towards producing the best sword possible today and I don't doubt that something amazing could come out. But it might have a totally different emphasis than the old swords. Like modern military rifles have a different emphasis.