Konobu finished up my order of kiridashi and marking knives last week, so I jumped on my little bicycle and peddled over to his forge to pick them up yesterday. He did a beautiful job!
Due to health problems, it took two years for Konobu to complete this order, but I have high hopes his recovery is now complete, so long as he doesn't overdo it.
I spent several hours sharpening and evaluating the kiridashi and experienced something that, judging from the content of some of the posts I have seen on SC, I think some of you may have experienced too.
My typical grit progress when sharpening a brand new blade in the shop is 300, 1000, 2000, and 6000 grit waterstone, and then finishing off with either a 10,000 grit manmade stone or natural stone of undefined grit. I abbreviate this process, however, for simple resharpening, or when on the jobsite.
As I worked the blade on the 6,000 grit stone, some deep scratches remained that I wasn't able to remove. It was like the 6,000 grit stone actually made things worse instead of better. When I next worked the blade on the natural stone, new deep scratches appeared. Yikes!
Fortunately, I knew the cause and took action. What had happened is that somehow I had contaminated one or more of my stones with the grit from a rougher stone, and that grit had become embedded in the surface of the next stone. This can easily happen especially when flattening stones, which was the last operation I had done before putting these stones away after my previous sharpening session.
To fix this, I put each stone under running water and scrubbed all 6 surfaces briskly with a stiff bristle brush and soap. I used an oblong-shaped natural sisal brush called a kamenoko or "baby turtle" brush available throughout Japan. Then I used a tsushima nagura stone under running water to scrub each stone's face thereby removing a tiny bit of each stone's surface, along with any contaminants. This solved the problem.
Sharpening stone contamination can come from any number of sources. Dirty water with suspended grit particles is the most popular method, as is grit from the previous stone remaining on the blade being sharpened, and being inadvertently transferred to the next stone. And don't forget contaminants in airborne dust and dirt that land on your stone's face without the control tower's permission. Sword sharpeners, for whom the beauty created by the sharpening stone is so important, are famous for waiting to sharpen the blades of customers that want the ultimate polish until the rainy season, when airborne dust is at its annual minimum.
Anyway, if you find that your stones are no longer producing the polish you expected, I suggest you take the time to clean and decontaminate your stones. Oh yea, and don't forget to use clean, fresh water to wet your stones, wash your blades before moving onto the next stone, and wrap your stones in newspaper to keep dust off them when you are not using them. Sharpening stones have feelings too.
All is well.
Stan