More learning curve

I ordered three nagura toishi from Mandarya in Japan. I now have a Botan, a Tenjou and a Mejiro, and they really are in a class by themselves. Unfortunately, I’m going to have to learn a lot of what I’ve been doing over again because these stones work so much differently from the Iyoto that I’ve been using.

I have an OLD nagura that I got from a woodworking store over a decade ago, rather than a certified stone like the new ones, and it is complete crap by comparison. The certified stones are finer, cut more quickly, and make slurry so fast that you wonder why they don’t just dissolve when water hits them. If you ever wonder if the quality of the nagura impact the polish, let me tell you that it is absolutely true… I used to doubt it.

Once again, I understand why Nihon Toigishi is a life-long vocation. There are so many factors, and every blade you touch is different.

My set of three Nagura Toishi from Mandaraya

Riddle me this…

Why in the world would an Iyoto (approximate grit size 800-1200 Japanese) bring up a hamon that is more distinct and complex than a 4000 grit synthetic water stone?

I can only think of one thing at the moment and that is the difference in the abrasive composition of the rocks. Natural water stones are silica based. Synthetics are often Aluminum Oxide or some offshoot of that general family, like Alumina Ceramic.  There is a distinct difference in the hardness of those materials.

Looking at the Mohs Mineral Hardness scale, Silicates range around 7. Right above those are Aluminum Silicates at 8. Right below Diamond (at 10) are Aluminum Oxides for the #9 slot.

Silicates, being softer, will break down faster than harder materials. Not only that, but I suspect they fracture (cleavage) differently. That would probably account for more of the differences that one will notice when using natural stones and synthetic ones.

So, here’s my silly question (and I can’t read Japanese to find out if anyone’s ever done this): why not make synthetic water stones with silicates instead of harder materials?

Frustration like I can’t even explain

I’ve learned a number of things since starting to polish John Smith’s tanto blade. I’ll sum them up in a list.

1. Synthetic stones are FASTER than natural stones.

2. Synthetic stones also leave deeper scratch patterns, which makes switching from synthetic to natural toishi a lengthy, torment-filled process.

3. Do not polish a blade before going to bed. Your control is probably not as super as you think it is.

4. Each stone reveals the deep scratch patterns left behind by stones earlier in the foundation polishing. If they’re deep enough, or far enough back in the process, you have to back up X-number of steps to eliminate them… and then build that area back up to where you’re currently at in the process. ARGH!

5. Synthetic stones really, at least the ones I own, do not produce the same finish as natural stones do. This goes back to my post about uchigumori grade polishing stones not producing a chrome-mirror finish. My Kitayama 8k WILL produce a mirror polish, but Uchigumori are often much higher grits than 8k.

6. This is why the post I made yesterday about Vital sharpening information from Eastern Smooth is so important. Your Uchigumori might approach 12k at the start, but what is it when the abrasives have really broken down? Something much, much higher.

I was messing with my Uchigumori last night

Shobudani Aisa. Honyama Renge (two different stones). Takashima Karasu.

None of these stones will put a chrome-like mirror finish on O-1 tool steel. They will, however give you a reflective polish that exhibits a very fine satin scratch pattern.

My Kitayama 8000 synthetic stone WILL do a chrome-mirror polish on O-1. This tells me one major thing, my Uchigumori have a grit range between 6000 (based on my Suehiro 6000 synthetic’s scratch pattern) and 8000 (perhaps). Although, the Kitayama is one of those that they say polishes as well as a 12k. To give a better comparison, I’d need another company’s 8000 grit stone to be sure. (Note to self, generate disposable income for a Norton or a Naniwa Chosera.)

Something occurred to me while I was doing all this. Hazuya and jizuya do not produce a chrome-mirror either. They’re simple X amount harder/softer/finer grit than benchstone size uchigumori. According to the book I own on sword polishing, the mirror polish on nihonto is not produced by stones. They bring that polish up by burnishing the surface of the blade with harder steel tools.

Basically, because I had a disconnect in my head about the process, I’ve been expecting a high mirror polish from stones that can’t do that… or if they can, it is well beyond the range of the stones I own and the skills that I have.

I will say one thing in favor of the rocks that I currently have, when used in order, properly, they make a noteworthy edge on a blade. Yow!

Another fine use for Iyoto

Japanese sword polishers say that the stone must fit the steel, and once in a while I see an example of how that seems to work. I was resharpening my CRKT First Strike, their interpretation of the Steve Corkum design, and I polished the edge right off it.

This particular knife is made from AUS 6-A, if I’m not mistaken, and is a tad softer than blades made from 440-C or AUS 8-A. I picked up an Iyoto fragment I had on my workbench, spat on it (heresy, I know), and gave the edge a little love with that. The results were impressive. It went from too polished to cut anything right over to shaving hair off my arm.

I think I can say that Iyoto fits softer stainless steel blades pretty well. Worth a try to see what sort of results you’ll get!

Rock For Sale

Bear with me, this is a mouthful.

Honyama Renge Uchigumori Koppa Toishi. There is also some phantom Karasu present. Without the Japanese, this is a polishing grade, natural water stone. The red and orange speckles are considered to be a sign of an excellent polishing stone. I may be mistaken, but that is a characteristic of Uchigumori stones from the Ohira mine.

As per usual, I’ve put the stone to use so that I can tell you more about it. If you’re polishing swords, this is an example of the last stone you’ll use prior to moving on to using hazuya and jizuya. It’s near-mirror polish and splendidly smooth to use. (It will produce a reflective scratch pattern, but not the ultra smooth perfect mirror surface that you’d expect on chrome.) However, because it is a Koppa stone (unfinished sides) you wouldn’t want to use it for swords.

Kitchen knives, razors, and carpentry tools are where this one would excel.

The photos are for scale. The pad is a 9 inch wide pad, so the stone is somewhat over 9 inches long, and well over 3 inches at the widest. Pardon my dirty index finger in the width photo.

Top view

Width approx. 0.5 in. to .625 in.

Backside

Price: $240 No longer being offered for sale.

The new stones are here.

I hate it when my eloquence is reduced to things like “Dude! Sweet!”

That’s about all I can say. I really like the Aoto and the Takashima that I got for myself. My supplier wasn’t kidding when he said that the Taka was the sort of stone that only someone with experience should use. It’s soft, smooth, but not as fiercely abrasive as Shobu Sugoro or Uchigumori.

I also acquired four other stones to “tail gate” at the hammer-in that I’m going to next month. One is an Aoto, and it is as spiffy as the one I’m keeping, the other three are Special. They’re easily the most expensive stones I’ve bought or used. Now I know why.

They’re Uchigumori, but they’re similar suita and graduated in hardness. Stone one is softer. Stone two is medium. Stone three is harder. They show some karasu and renge. Using them one after the other yields something truly beautiful, and sharp.

I’m having a crisis of conscience about selling them. That’s when you know you’ve purchased well.

This is not good.

A little research has appeared under my nose, along with one supporting personal bad experience. My toishi supplier may be trying to cheat people.

I have learned the following thing about Japanese business practices. Once a price is agreed upon, paid, and the item delivered, it is UNETHICAL of a business person to ask for more money. In my case, my supplier’s shopping cart system undercharged me for shipping. He sent the stones anyway, and came to me looking for the balance of the undercharge.

At this point, things just became unethical. There is consumer protection for things like this. I could, and my Research Partner in Japan may well, report my Toishiya-san to the Government.

So, if you are ordering things from Japan and an issue comes up after you’ve paid, there may be reason to remind your vendor of “The Bye-bye Clause” in Japan’s Consumer Protection.

I’ll be looking for alternate stone resources in the near future.

And then my eyes refused to process.

I found a retailer who sells Koma-Nagura and Chu-Nagura. Of course, they’re in Japan and don’t speak English. Fair enough, since I can only swear, count to 100, order food, ask where the “Honorable hand washing place” is, and thank people in Japanese.

I can read prices. Mostly because they’re displayed in English, but bear with me.

A simple Meijiro Nagura, about 6.5 inches long, by 1.25, by 1.625 is just over $90. That is NOT a Koma. That’s a grade below.

My eyes refuse to process the cost of Koma and Chu at the sizes that would be useful for large blade or sword polishing. I nearly got a cramp in my soul. Synthetic stones for these two may be a reasonable approach to the issue.

Ow.

Looking forward a week or two

I plan on making a larger than usual order for stones this month. The question is, as always, what to get.

There are a few things on my mental list that ought to be addressed first, before I start considering what other stones might fill out the order. That being said, I should ask my supplier about chu and koma nagura, as I’ve no idea whether or not he has them or can get them.

On the mental list already are a selection of Iyoto, some Aoto (one of which will be for me, as I don’t own one), and a certain Takashima stone that I’ve had my eye on for a while now.

I could stop there. The postage is going to make me howl one way or another, so I might as well just cope.

I ought to add a few kinds of Uchigumori to the list. If I can find a white lotus  Renge Suita, that would be an excellent addition to the purchase. A Murasaki Suita would also be interesting.

We shall see, I guess.