Iwasaki and Jnats (part 3)

[DrNaka]

May 11, 2011

Iwasaki and Jnats (part 3)


Continued from Iwasaki and Jnats (part 2).

When I asked Iwasaki san and Mizuochi san how they sharpen their razors Iwasaki san asked me what I think of edge profiles.
He made forms with his hands like this:

Iwasaki san made a form like this (This is not Iwasaki san's hand) "You can form a edge like this. It is a straight edge."

Iwasaki san made form like this too (hamaguriba). "The edge can be like this (hamaguriba) too."
"I observed beard hair cut with both edges and found that the straight edge makes a straight cut and the hamaguriba edge makes a diagonal cut."
I said "So the straight edge is better."

"The answer is not so easy." replied Iwasaki san "It depends on skin and hardness of the beard hair."
"If the skin is hard and beard hair soft a straight edge is good. If the skin is soft and hair is hard a hamaguriba edge is better." "Japanese in general have a harder skin so our razors have straight edge, But we advice barbers who have many western customers to sharpen their razors hamaguriba or if straight edge more wider angle."
"The angle of the edge is very important so if you have a razor for yourself you must find out which angle is best for you."

To be continued ....

[thebigspendur]

Oh-Oh now you've gone and done it. In addition to all the fears and phobias the guys have about shaving now they will be worried about custom altering the edge of the razor to fit their face.

[DrNaka]

Oh-Oh now you've gone and done it. In addition to all the fears and phobias the guys have about shaving now they will be worried about custom altering the edge of the razor to fit their face.

Or the guys go for a quest to buy a razor which have a ideal edge to fit their face.

But I think that is nothing new about it.

[JimmyHAD]

Thank you for the insightful post DrNaka. Visualizing honing to accomplish the (hamaguriba) edge the only way I could see to accomplish it would be to make the razor with a thicker spine, or to build the spine up with tape if it was a "normal" spine meant for the 'straight edge'. Am I interpreting the information correctly ?

[onimaru55]

"If the skin is hard and beard hair soft a straight edge is good. If the skin is soft and hair is hard a hamaguriba edge is better." "Japanese in general have a harder skin so our razors have straight edge, But we advice barbers who have many western customers to sharpen their razors hamaguriba or if straight edge more wider angle."
"The angle of the edge is very important so if you have a razor for yourself you must find out which angle is best for you."

This is interesting, a hamaguriba (convex) edge is more common in Europe due to the use of pasted strops to develop the edge, yet usually most on the USA fora advocate straight edges. Just an observation.

[JimmyHAD]

Looking at DrNaka's illustration of the hamaguriba edge I was reminded of Tim Zowada's technique of creating a double bevel using 3 layers of tape for the final honing. Maybe I'm way off base but that was my interpretation.

[DrNaka]

Thank you for the insightful post DrNaka. Visualizing honing to accomplish the (hamaguriba) edge the only way I could see to accomplish it would be to make the razor with a thicker spine, or to build the spine up with tape if it was a "normal" spine meant for the 'straight edge'. Am I interpreting the information correctly ?

I did not ask Iwasaki san how to make the hamaguriba edge.
I did not write yet but Mizuochi san said to me that he use 8 figure honing for the finish honing and makes a straight edge.
I assume for hamaguriba edge you "wobble" a bit at the last stage when the razor leaves the stone.

Jim san will visit Iwasaki san soon so I hope he can ask Iwasaki san or Mizuoshi san direct for exact info.

[mainaman]

The way I imagine the edge shape is achieved is not on the stones but when stropping.
Hard leather stropping surface (paddle strop) will give the V, while hanging strop will give convexity to the edge.

[JimR]

Hmmm...I've encountered the term "Hamaguriba" before, but it was in terms of the entire profile of the blade.

Here are links (Japanese language, but there are pictures)
Wikipedia
Tojiro.net (Also, scrolling down will show a discussion of Kobatome.)
Tojiro.net lists it as a Western knife profile.


DrNaka, could this be another way of referring to "Kobatome", or double bevel as we call it here? Iwasaki Kousuke-san called it "Ha tome" in his manual.

[mainaman]

Hmmm...I've encountered the term "Hamaguriba" before, but it was in terms of the entire profile of the blade.

Here are links (Japanese language, but there are pictures)
Wikipedia
Tojiro.net (Also, scrolling down will show a discussion of Kobatome.)
Tojiro.net lists it as a Western knife profile.


DrNaka, could this be another way of referring to "Kobatome", or double bevel as we call it here? Iwasaki Kousuke-san called it "Ha tome" in his manual.

In the kitchen knife circles people refer to the geometry of the bevels as hamaguriba. The geometry of the blade is always convex (excluding traditional Japanese knives), however recently there are American makers that do flat grinds.