Determining the grit of a waterstone
Derek Cohen (in Perth, Australia)
>I spent part of Saturday at the Perth Woodworking Show. One highlight for me was chatting with Terry Gordon (of HNT Gordon planes). He is also now selling Adria saws, which I had a chance to try. Very nice indeed. If I did not already have the LN Independence dovetail saw, I'd buy the Adria version like a shot. But I digress.
One of my purchases was a Japanese waterstone. This is a natural stone, grey in colour (or color). The grit was not marked and the guys selling it did not know what to rate it. "It's natural - you can't rate it", he said. "Yes, but where do I place it among my other waterstones?" I asked. He couldn't say specifically but defined it as a polishing stone, one that he had himself used very successfully. I know this store well and so, trustingly, I decided to take a chance since it was going quite cheaply as a Show Special. This store usually stocks King stones, and is where I bought my 800, 1200, 4000, and 6000 King stones.
Later that afternoon I sharpened up a couple of blades (inspired by Terry, I just had to see if I could also slice end grain on my shooting board with the Try Plane. By George I could!). But I digress.
How does one determine the grit of an unknown waterstone? By the degree of shine inparted on a blade? If this is the case then this blade is not up to 6000, which leaves a mirrored surface. The "grey stone" left a matt surface. I could not see obvious scratches in the metal. The surface of the stone to the touch actually felt a little more soapy that my 6000 stone. And it produced a very nice edge. Sharper than the 6000? - I cannot say at this stage.
Any ideas?
Regards from Perth
Derek