runagmc Posted August 12, 2012 Report Posted August 12, 2012 An example is not a generality And yet, you have no problem making a generality like 1.5mm...
cabowen Posted August 12, 2012 Report Posted August 12, 2012 Further discussion of this topic is a waste of time. Physical evidence is plentiful and clear. There are published photos of dozens and dozens of sectioned Japanese blades, many complete with hardness testing across the profile, from all periods, that show beyond any doubt that the edge is through hardened and thus, provide a definitive answer the op's question: no, the hamon is not only on the surface and therefore you can not polish off the hamon. The article Adam linked to also clearly answers the original question. Now, does the peak of the hamon transfer completely through to the other side? Have you ever seen a sword with an identical hamon on both sides? Or a sword with two completely different hamon? Inspection of nearly any sword makes it obvious that it does not carry through so polishing will alter the habuchi. Again, Adam's article proves this conclusively. This, however, was not the original question. Next.
ROKUJURO Posted August 12, 2012 Report Posted August 12, 2012 ......Do you have the measurements of these cross sections? When nioiguchi is near the shinogi do you think hardening goes through the entire blade shingane included? Jacques, as I pointed out:....' a YAKIBA will always go through the material of the blade as long as the cross section has a sufficient carbon content to be able to harden.....' Chris said the same in other words. In most cases the SHINGANE will not harden because of an insufficient carbon content. I don't have correct measurements of the blades in question, but we know that the MUNE rarely exceeds 8 mm, YOROIDOSHI excluded. Even if one or two millimeters of the steel core of a very thick blade should not harden, you will not get down to that point by polishing (hopefully). The hardenability limit of steel is 0.22% carbon.
Jacques Posted August 13, 2012 Report Posted August 13, 2012 Hi, I would come back to the pictures of the cross section. Scientifically speaking, a picture or a graph without comment is not acceptable. As i own the article related with these cross sections, i can say that its subject is only construction of the sword and in no way about tempering or hardening. Nobody can say if the dark triangle is hardened or not (even if we can reasonablily think it is). Carbon steel is carbon steel and it must obey to physics laws and it is well known that carbon steel has a poor hardenability (it's why it is often alloyed with other components to increase its hardenability). The difference in the 2 sides is very distinct. The new side has a harder temper than the old side it seems, the steel works quicker on the stone than the new side. Harder steel always takes a little more effort to whiten with the uchigumori. Incidently, the smudges of the koma nagura came out quickly on both sides, but when working the koma nagura it was very easy to leave scratches. About the experience on Usagiya site, if you read correctly (and not only what you want to see) the comment of the polisher you will see that he says the steel on the old side is softer than the "new" side. that means steel is less hard on the old side than the new side and more deep you go less hard is steel. Now Nioiguchi. some people claims Nioiguchi cannot become invisible, i wonder on which argument this claim is based. At first glance it is only opinion. Now i have a question. If nioiguchi goes so deep in the thikness of a blade (more than 2 mm) Why we never see it coming out on the other side specially towards the kissaki where the blade is not thick or near the hasaki ? I would love to have a comment of this oshigata of a wakizashi attribued to Sadamune (known as Monoyoshi Sadamune)
cabowen Posted August 13, 2012 Report Posted August 13, 2012 You are wasting your time and everyone else's here. Do some homework. There is ample evidence easily found. You were wrong, it's ok.
Recommended Posts