Mekugi-ana punching

[itsoverthere]

Hi all,

 

As I understand it, distinguishing whether the mekugi-ana is/are punched or drilled is thought of as a fairly reliable way of determining whether or not a piece is earlier or later than the beginning of the Shinto period. Given that during the Shin-shinto period it became much more desirable to have an older blade I was wondering if the artists/forgers who, in response to this, were producing new "old" blades resorted to punching the mekugi-ana (or at least making it appear so) in order to further deceive? Does anyone have any thoughts on this?

[nagamaki - Franco]

Greetings,

 

There is a Gendai-to rumored to be a Koto Juyo down to the punched mekugi-ana, now, whether this is true or not, it clearly demonstrates the dilemma of using a punched mekugi-ana to determine the age of a sword. In a somewhat similar manner, using the type of mekugi-ana to determine age is not all that much different than using ubu-ba as the determining factor in the age of a sword, while it might affirm a correct judgment in the age of a sword, it might also be affirming a mistaken judgement in the age of a sword. If only it was that easy!

[remzy]

Franco is quite right i think.

Also, i was wondering if they punched the mekugi ana cold or hot, does anybody know ?

[itsoverthere]

Sorry, didn't mean to suggest that this might be a surefire way to determine Age. It's just that I've heard people say oh it looks punched which means X. I realise why this might be so but also wondered just how much such thinking might also be misleading. Thanks Franco for the info.

 

For some reason I thought they were punched cold but given my very limited knowledge that could very well be wrong.

[Brian]

Anyone feel free to correct me, but I understand that the ana is punched through with a red hot punch, working from both sides until they meet in the middle.

The presence of a punched hole would not 100% confirm older age, but the presence of a drilled one leans away from an earlier blade unless o-suriage at a later date.

They aren't conclusive by any means, but used in conjunction with the other indicators to form an opinion.

 

Brian

[IanB]

Brian, It is the object to be punched that has to be hot. The punch itself has to be cold so that it is hard relative to the metal it is punching the hole through. In a former existance I once spent a day at a steel works and watched the ends of cast billets, about 2' x 2' being cut off by a circular saw of steel. Because the billets were bright red-hot, the saw simply sliced through them.

Ian Bottomley

[Henry Stewart]

Brian,

 

The reason for punching the Mekugi-ana was that the HSS.Twist Drill simply did not exist in times gone by when these earlier swords were made thus it was the simple way of making a hole. The punch would have a cutting end tempered to light purple thus it was hard enough to keep an edge but not brittle enough to shatter when struck.

Examination of the interior surface of the resultant hole would show it was free of the tell tale concentric rings which would have been made by a twist drill. This tends to infer the older age of the piece but would be taken along with other indicators.

 

Henry.

[Brian]

I understand the logic that the nakago is the part that needs to be heated and the punch hard, however I do have a distant memory somewhere of seeing something on film where it was the punch that was heated and not as much the nakago. Not sure exactly how you would heat the nakago hot enough to punch through it without affecting hardening of the blade, except for using elaborate masking off of the blade with copper or water.

I am not sure if a heated tip of a punch would also heat the area being punched and allow for a slow hole to be formed, or if my memory is just playing tricks on me.

Of course a hard punch could be worked through the nakago without any heating, but I do think that there was heat involved. The rounded edges of the hole also indicate some heat and "melding" as opposed to hard "chippy" edges of a cold chisel.

 

Brian

[Baka Gaijin]

Good Evening all,

 

This is a bit of a sideways question regarding Mekugi - ana and modern era Japanese Sword Laws.

 

Am I correct to say that once a Mekugi - ana is formed in a blade, that goes toward the Smith's yearly total?

 

So, if a Mekugi - ana is formed and the blade subsequently develops a fatal flaw on polishing, before going to end user, can the blade be rejected and destroyed, without affecting the Smith's yearly total?

 

Cheers

 

 

Malcolm

[Henry Stewart]

Brian

 

To be honest I have never heard of a heated punch; I am not saying that somewhere it does not occur,but as a once worker with metals and metal forming it is new to me. You are entering a zone of discussion which is long; there is the question of hot and cold punching and forming of steels and other alloys, the types and treatment of steels and other alloys; methods of hardening and tempering,comparisons of degrees of hardness, available forces to be applied,the use of mandrell tools ,etc,etc. Dont forget the nakago is of softer metal than the blade and therefore is more maleable and could be heated without the need to sink heat away. If you would like to take the discussion further I would be glad to oblige to the extent of my limited knowledge.

 

Henry

[remzy]

I am afraid that this is yet another secret of the craft that might have been lost..

 

I would think that they might heat the nakago a bit in the forge than place it over a bright red copper block like they use to straighten the blade after yaki-ire to keep it hot, then proceed to punch it with a cold punch, but all of this is speculations based on common knowledge, maybe they used more sophisticated technics that got lost.