Sharpening Japanese Chisels in 2023

[Keegan Shields]

I'm not sure if you're implying that if there had been more iron resources, they would have used metal bodied planes; there were no metal bodied planes before the 19th century.

Also, certainly carpentry tools were being manufactured throughout Japanese history, they have a centuries old woodworking tradition.

The katanas were mentioned as an example of the manufacture of a cutting instrument forge welding irons with different carbon content. The same technology applies to more mundane devices like chisels, plane irons, etc.

Fair point. Metal bodied planes were probably a bad example to use as they are a pretty recent innovation in the west.

I always thought katanas were made from a single steel blank. The spine (less hard) and edge (harder) are hardened to different levels allowing it to take a keen, durable edge while also allowing the spine to flex. A cool Japanese innovation.

Until recently, I didn’t realize that it was this differential heat treatment that gave the katana its signature curve.

Do I have something wrong here?

[Tony Wilkins]

I guess in the grand scheme of things Ancient Rome was relatively recent

[Rafael Herrera]

Just to make sure, I checked one of those katana making videos on YouTube.

A blank of high carbon steel (kawagane) is folded around a blank of low carbon steel (shingane). Then that is hammered and stretched to the shape of the sword. The hardening process affects the whole blade. Only the outer shell hardens, the shingane does not harden.

Of course, there's a lot more to this art, here's the video I watched. The lamination is shown around minute 22.

https://youtu.be/gxwWf-MfZVk

[Chuck Hill]

William, do you have a link to the stereoscope that you use?

[Keegan Shields]

Thanks Rafael! I learned something new and I'll check out the video.

[William Fretwell]

The Will Strubin Wetzlar dissecting microscope. It’s old. Universities sell off their old stuff very cheap, they have lots of new money to spend. You have to strip and lubricate but $2000 new, $66 disposal. Microscope $5000 new $102 disposal.
Once cleaned and lubed they work fine. The optics are still superb.
I would stay away from the really old stuff 50 years plus, things did get better. Helps to know about model years for microscopes. The stereoscopes really took off for printed circuit board assembly, lots out there, not all zoom.

[Chris Pyle]

Let me try to be more clear about the two points.

1. Carpentry was a less important vocation than making war in feudal Japan, therefore making something like a katana with the available steel/iron would have taken precedence over a metal smoothing plane or timber framing chisel. Given the scarcity of iron ore, its no wonder Japanese carpenters used wooden plane bodies and developed chisels with laminated blades.

2. The fact that katanas are traditionally made with many layers of folded steel is the practical solution to the problem of impurities in the steel that was used causing a weak spot. This is my attempt at showing another example outside of woodworking where a bug is turned into a feature over time. All that extra work to fix a problem turns into some mythical benefit to admire. The point has nothing to do with material savings.

Hopefully that helps clear up what I was trying to convey.

This sounds like an attempt to reduce something unnecessarily.

Would you mind answering some specific questions?

Do you believe metal body planes superior? Do you believe all steel plane blades are superior to their laminated counterparts?

I think the Japanese, as a culture, pursue singular things to the highest degree. They iterate throughout their lives on singular tasks and attempt to produce the highest quality work. This is repeated over generations in various domains. Their tools and methods are the result of this continued iteration over centuries and many of their tools and practices have been taken from other cultures (China, perhaps Korea?).

When steel became more readily available, why didn't they "improve" their product?

[Luke Dupont]

FWIW, I have a kanaban, but I recommend skipping it and just going to a diamond stone. A combination 400/1000 grit diamond plate is great. You'll use the 1000 grit side primarily, but you may occasionally need to do heavy grinding, in which case you'll need at least 400 grit.

Most Japanese woodworkers I know also tend not to use the kanaban so much and just use diamond plates as well.

Beware of cheap kanaban, by the way. Mine did NOT come flat and I spent considerable time getting it perfectly flat. Diamond stones are usually better, but buyer beware -- make sure you get a perfectly flat diamond stone.

Next up would be a water stone, maybe around 1000-2000 grit, and another around 4000-6000 grit to finish on. Maybe a finer waterstone or a Jnat after that for an ultra fine edge.

I'm a bit anachronistic and actually sharpen all of my Japanese tools with oilstones -- primarily a vintage washita and arkansas stones. They seem to work rather well with Japanese steel and I never have to worry about rust. They also cut better than cheap Japanese natural whetstones that I own, but I should state that I don't own any particularly good/expensive jnats. Maybe one day I will. My sharpening set up is not much different than what people were using 150 years ago in Europe and America.

As others have said, free hand a flat bevel. Another anachronistic point of mine, but I find that if you get the bevel perfectly flat, especially with Japanese tools because they're so thick, then as you're sharpening, you will find that two perfectly flat surfaces rubbing against eachother with a lubricant present will cause a vaccuum effect where they stick together quite solidly on occasion. You'll be pushing or pulling along and then the bevel will just "grab" to the stone and stop all of the sudden, causing you to ruin the angle and create a micro bevel. If this happens, it's back to the coarse stone... and it happens often enough if you have a perfectly flat bevel, that I actually began putting an almost imperceptible amount of curvature on the back of the bevel. Actually though, I've found you can keep 80-90% of the bevel completely flat and just subtly round off the very top of the bevel (the soft iron side) to break that hard corner, and this problem will occur way less.

Not many people seem to complain about this issue other than me, so maybe I'm just getting things "too flat" for my own good, but there's my 2 cents if you happen to encounter this phenomenon on a regular basis.

FYI, sharpening Japanese tools in 2023 isn't much different from sharpening them in 1723. I quite like my ancient natural stones, and many Japanese woodworkers I know do also. There's a few more conveniences available these days such as diamonds and synthetic, but it really doesn't change much tbh. The important thing is just to get the skill and experience, so start practicing and learn to free hand!

[Warren Mickley]

FYI, sharpening Japanese tools in 2023 isn't much different from sharpening them in 1723. I quite like my ancient natural stones, and many Japanese woodworkers I know do also. There's a few more conveniences available these days such as diamonds and synthetic, but it really doesn't change much tbh. The important thing is just to get the skill and experience, so start practicing and learn to free hand!

You have information on Japanese sharpening in 1723?

[Keegan Shields]

Do you believe metal body planes superior?

Superior is a subjective word. But yes, for my purposes I believe so. Wood moves when the humidity changes, ductile iron does not. I’ve never needed to use a tachi kanna to flatten or hollow the sole of my LN 4 1/2. I prefer the additional weight of a metal bodied plane and the integral chip breaker to limit tear out. As I understand it, the addition of a chip breaker on kannas appeared only after WW2, demonstrating that the traditional kanna could be improved upon. I also find the Stanley type mechanisms to control blade protrusion easier to use than tapping with a hammer.

Do you believe all steel plane blades are superior to their laminated counterparts?

No. But why bother with lamination if you don’t have to? Why add unnecessary complication if there is no performance benefit? Why fold a steel blank 1000 times if you don’t have to? I believe the answer is - when a process takes on a life of its own. When myth and tradition (which I cyclically see as marketing) become the brand and thus the selling point.

The role of marketing is to differentiate a product and make it special, raising its perceived value. There are wild product claims made all of the time, and the consumer is often left trying to figure out what matters and what is marketing. Some might remember the original Copperfit advertisements that made miraculous claims about the healing powers of copper. Spoiler alert - it doesn’t…

As an aside, I have great respect for the Japanese cultural traditions of precision. Japanese watch (Sako) and optics manufacturers (Light Optic Works) are great examples of this.

[Chris Pyle]

Do you believe metal body planes superior?

Superior is a subjective word. But yes, for my purposes I believe so. Wood moves when the humidity changes, ductile iron does not. I’ve never needed to use a tachi kanna to flatten or hollow the sole of my LN 4 1/2. I prefer the additional weight of a metal bodied plane and the integral chip breaker to limit tear out. As I understand it, the addition of a chip breaker on kannas appeared only after WW2, demonstrating that the traditional kanna could be improved upon. I also find the Stanley type mechanisms to control blade protrusion easier to use than tapping with a hammer.

Do you believe all steel plane blades are superior to their laminated counterparts?

No. But why bother with lamination if you don’t have to? Why add unnecessary complication if there is no performance benefit? Why fold a steel blank 1000 times if you don’t have to? I believe the answer is - when a process takes on a life of its own. When myth and tradition (which I cyclically see as marketing) become the brand and thus the selling point.

The role of marketing is to differentiate a product and make it special, raising its perceived value. There are wild product claims made all of the time, and the consumer is often left trying to figure out what matters and what is marketing. Some might remember the original Copperfit advertisements that made miraculous claims about the healing powers of copper. Spoiler alert - it doesn’t…

As an aside, I have great respect for the Japanese cultural traditions of precision. Japanese watch (Sako) and optics manufacturers (Light Optic Works) are great examples of this.

Superior is definitely subjective but your answers help explain why you were so reductive about Japanese tools and practices.

Superior to you doesn't mean superior performance, necessarily. It means ease of use and maintenance or those carry heavy weight in your final grading.

I wonder why these really high end infill planes aren't brought to the Kezuroukai competitions to win the award and show everyone they've been using unnecessarily finicky tools that were developed before resources were plentiful?

You believe Japanese tools haven't "evolved" because of myth and tradition?

[Derek Cohen]

Keegan, if you believe that the performance of laminated blades of Japanese chisels is something made up by the publicity department, then you need to read the tests I have done:

http://www.inthewoodshop.com/ToolRev...g-5Steels.html

"There were relatively good performances from 3V and M4, and superlative performances from Koyamaichi laminated white steel."


http://www.inthewoodshop.com/ToolRev...sCompared.html

"The PM-V11 and the White Steel really do deliver. The gap between them and the A2 and O1/HCS is very large."


Regards from Perth

Derek

[John Kananis]

For years I've been advocating the use of diamond paste as a sharpening medium. (I really don't understand how this hasn't caught on) Raises a burr in pm-v11 in a half a heartbeat. I use the water-based Norton product found at gramercy. I used to use mdf as a substrate but I have the steel plates from lv for a while now and really love them.

[Chris Parks]

Here is a video on how sharpening is taught in Japan.

[chuck van dyck]

I have a tsushima stone from Suzukitool. I go back to a 1200 king or 1k shap glass when needed, but typically just return to the tsushima at first clue of needing a hone. Is it the “the best” system? Definitely not, but it is definitely good enough and its fun sharpening handmade irons on millennia old rocks. Searching the internet for “the best” is a losing battle. Just find a system you enjoy and it’s probably good enough.