Thread: Katana-Kagi (swordsmith) asking for input

Thanks Jim,

My thoughts exactly. I need a good quality kamisori to understand the correct geometries as well. That is good news about the Swedish steel. I can get it from Uddeholm here in the US. Any idea what grade they are using? O-1, A-2 etc or maybe some other designation they may use?

Thanks again.
Dan

If anyone is interested-you can see the building of my KAGI-BA (sword forge) from the ground up here. After several years absence from bladesmithing I am starting all over again.

Hi Dan. Nice to see you on another forum.

I have seen some debate in the past on honing up the ura as well as the omote. From what i understand, the suggested method is more of an 80/20 omote/ura honing. I only own one kamisori (nothing special) and it was honed in this fashion. I have wanted to explore the difference with only setting a bevel on the omote, but haven't taken the time yet on my own razor.

I wish i had better insight for you regarding bevel angles on Japanese straights. Bevel angle of western style straights has been extensively discussed though it would take a little searching to see if Japanese straights have ever made their way into those conversations. From the little reading and application i have done on my own razors it seems that western style razors can range from roughly 15 to 25+ degree's.

If i can help in any way, please let me know. I only own the one, but I would be more then happy to loan it to you if you would like to have a comparison in-hand. I am sure others would gladly supply measurements and photos if needed/requested.

-Donovan

Donovan,

The Omote/Ura honing debate is not isolated to Western users. Barbers were/are taught several ways. My barber, who gave me my first stone and Kamisori, taught me a rough 10/1 ratio, saying that Ura honing was more to help control burr formation rather than actual honing. My wife's Uncle, who is also a barber, was taught not to hone the Ura at all.

Mizuochi-san, the current maker of Iwasaki kamisori, said that he hones his at something closer to 2/1, perhaps 1/.75.

Personally, I have gotten my best edges using a steep ratio. It all changes depending on the size of stone you use and the pressure you apply, but when using a smaller razor hone I use roughly 5/1.

Dan, I'll call some people and see if they're happy sharing more details about their steel.

Wow!

You guys are great. This is all good info.
Donovan I may take you up on the offer. I will cover shipping.
I am definitely in the honing the ura side only to control the burr camp when it comes to plane blades and single bevel knives. They have a layer of hardened tool steel forge welded to one side.

If the Ura was honed as much as the omote
1) The hardened steel would get progressively thinner until it disappeared. Whereas honing only or mostly the omote side, the razor becomes more narrow but the thickness of the hard steel stays mostly the same.
2) The hollow would gradually disappear making it more difficult to remove the metal because of the increased surface contact of the flat.

I see these razors as a single bevel tool.
When honing the ura-the edge and the top only contact the hone creating small flats-correct? This would establish a flat plane and the omote bevel angle would be relative to this plane.

However, having said all that-I understand the dangers of transferring the characteristics of one tool to another. But this idea of flat ura-beveled omote is so prevalent in Japanese tools I don't see it changing radically for razors.

At this point this is just all conjecture on my part. As Jim said using a kamisori will answer many of my questions.

Jim,

I appreciate any effort to find out about steel choices.

Dan

Dan,
the single bevel notion is correct, the back is hollowed and is in essence identical to a plane blade or traditional kitchen knife.
The difference is the Omote, for planes it has to be flat, for knives it has to be convex, for kamisoru it has to be hollow ground.

As far as steel, Swedish and white #2 are the most common. White #2 takes the keenest edge of all traditional carbon steels used in Japan.
Iwasaki uses Swedish steel because he thinks the steels made in japan are not consistent from batch to batch. From what I have heard Swedish Steel he uses is close to properties of White #1.

Originally Posted by Danocon

Wow!

You guys are great. This is all good info.
Donovan I may take you up on the offer. I will cover shipping.
I am definitely in the honing the ura side only to control the burr camp when it comes to plane blades and single bevel knives. They have a layer of hardened tool steel forge welded to one side.

If the Ura was honed as much as the omote
1) The hardened steel would get progressively thinner until it disappeared. Whereas honing only or mostly the omote side, the razor becomes more narrow but the thickness of the hard steel stays mostly the same.
2) The hollow would gradually disappear making it more difficult to remove the metal because of the increased surface contact of the flat.

I see these razors as a single bevel tool.
When honing the ura-the edge and the top only contact the hone creating small flats-correct? This would establish a flat plane and the omote bevel angle would be relative to this plane.

However, having said all that-I understand the dangers of transferring the characteristics of one tool to another. But this idea of flat ura-beveled omote is so prevalent in Japanese tools I don't see it changing radically for razors.

At this point this is just all conjecture on my part. As Jim said using a kamisori will answer many of my questions.

Jim,

I appreciate any effort to find out about steel choices.

Dan

Dan,

I think you are slightly mis-imagining the structure of a Kamisori. The Ura is extremely hollow. Even if you honed only on the Ura, it would take a very long time to flatten out and remove all of the hagane (though, of course you are right about the thinness of the Hagane). Even so, doing that would eventually lead to the edge contacting with the Jigane on the Omote, which is why Kamisori are honed primarily on the Omote--to get all the jigane away from the edge.

Also, and I'm not sure how relevant this is, Iwasaki razors are hardened to a very high level--about 64 Rockwell. This is a point of pride with them, and a real pain for some of us honers. Just another data point.

Originally Posted by JimR

It all changes depending on the size of stone you use and the pressure you apply, but when using a smaller razor hone I use roughly 5/1.

Thanks for the clarification Jim. The edge on my kamisori provides a decent enough shave but it could probably be better. More testing is needed as you have re-sparked my interest! I will have to spend more time this week on it focusing on the pressure i am applying.

Originally Posted by Danocon

Donovan I may take you up on the offer. I will cover shipping.

Please don't hesitate Dan. I have plenty of straights to use and would gladly put a new edge on it if you even want to try shaving with it as well as use it to study the design. Let me know.

Originally Posted by D.Sweet

Please don't hesitate Dan. I have plenty of straights to use and would gladly put a new edge on it if you even want to try shaving with it as well as use it to study the design. Let me know.

Donovan,

Sent you a PM.

Dan

Originally Posted by JimR

Dan,



Also, and I'm not sure how relevant this is, Iwasaki razors are hardened to a very high level--about 64 Rockwell. This is a point of pride with them, and a real pain for some of us honers. Just another data point.

This is a relevant point. The balance of keenness, sharpen-ability and wear resistance.

It is a balance no matter what you are cutting. In shaving how would you rank the three.

I realize this is also somewhat of a personal preference. One person may not mind sharpening often if he can get a shaving edge quickly, where another would prefer to hone more at one time to get a longer space before having to hone again.

Dan

Originally Posted by Danocon

.
The hardened steel would get progressively thinner until it disappeared. Whereas honing only or mostly the omote side, the razor becomes more narrow but the thickness of the hard steel stays mostly the same.

A minor point here: If a razor is kept sharp and free from damage, honing (or rather touching up) will remove only tiny amounts of metal. Regardless of the way you hone, any kamisori has enough steel to it that it could be used daily for hundreds of years without getting through the hagane.

It's not like a plane blade where you remove measurable quantities of metal.