Re: Sharpening of the garden-variety?
Posted: Sun May 29, 2016 6:46 pm
Hi Vips,
No conclusive tests that I know of. If you get the chance to handle good quality Japanese nats, take notice of the sides and bottom of the stone to see what it looks like when rough. These sedimentary stones start out as mud and are layered. As the deposits age and are compressed, the stone is slowly metamorphosed into glassy material (chert or flint I think). You can find deposits anywhere along this continuum from muddy stone to chert. There seems to be a sweet spot, just before they get too glassy, which produces good finishing stones.
So, after identifying the right kind of stone, make sure it's not too soft or too glassy. After that you need to test how fine it is and how well it cuts. Unfortunately, the only way I've found is to flatten a section and test by sharpening a piece of steel. I carry an old kanna blade or chisel to do the test. The laminated Japanese blades are best as the soft jigane makes a very black slurry if the stone is cutting well and you can also see if the hagane is getting a fine finish.
Hope this helps.
Gadge
No conclusive tests that I know of. If you get the chance to handle good quality Japanese nats, take notice of the sides and bottom of the stone to see what it looks like when rough. These sedimentary stones start out as mud and are layered. As the deposits age and are compressed, the stone is slowly metamorphosed into glassy material (chert or flint I think). You can find deposits anywhere along this continuum from muddy stone to chert. There seems to be a sweet spot, just before they get too glassy, which produces good finishing stones.
So, after identifying the right kind of stone, make sure it's not too soft or too glassy. After that you need to test how fine it is and how well it cuts. Unfortunately, the only way I've found is to flatten a section and test by sharpening a piece of steel. I carry an old kanna blade or chisel to do the test. The laminated Japanese blades are best as the soft jigane makes a very black slurry if the stone is cutting well and you can also see if the hagane is getting a fine finish.
Hope this helps.
Gadge