Ohishi Waterstones?

[Patrick Chase]

On a related note: My understanding is that L-N started distributing "Ohishi" (not the real brand name by many accounts) because they stopped doing business with Harrelson Stanley (a.k.a. "Shapton USA"), who was the sole US distributor for Shapton at the time.

Shapton now has new distribution in the US, so it will be interesting to see what L-N does going forward.

I've seen claims that the "house brand" resinoid stones distributed by "Metal Master" are sourced from the same manufacturer as Ohishi and may be the same. I have the MM 10K and I've used the Ohishi 10K, and they're very similar in terms of scratch pattern and texture/feel. Beyond that I have no direct information.

[Jim Koepke]

I've seen claims that the "house brand" resinoid stones distributed by "Metal Master" are sourced from the same manufacturer as Ohishi and may be the same. I have the MM 10K and I've used the Ohishi 10K, and they're very similar in terms of scratch pattern and texture/feel. Beyond that I have no direct information.

With all of these different makers marching to their own specs, how does one know if this 10K is any finer a medium than another maker's 8K?

To the best of my knowledge my 8K Norton stone has 3µ abrasive particles. I am sure smaller particles would make a slightly sharper edge, but is it really worth it? My skill level seems to do fine with 3µ. It doesn't seem getting sharper would really improve much other than my ego.

jtk

[Patrick Chase]

With all of these different makers marching to their own specs, how does one know if this 10K is any finer a medium than another maker's 8K?

To the best of my knowledge my 8K Norton stone has 3µ abrasive particles. I am sure smaller particles would make a slightly sharper edge, but is it really worth it? My skill level seems to do fine with 3µ. It doesn't seem getting sharper would really improve much other than my ego.

jtk

As you say, you have to look past the rated grit # and use the abrasive particle size as a guide (but don't treat it as Gospel). Most manufacturers either state that outright, or state what standard they comply to (i.e. JIS-1998, etc). Neither Ohishi nor MM state their abrasive size AFAIK, so in cases like that you're basically trusting the vendor.

The binder and abrasive used further modify the "harshness" of the sharpening medium. I would never use the edge resulting from a 3 um diamond paste, but as you say there are 3 um waterstones that leave perfectly reasonable results. It's possible that your Norton may use a somewhat frangible abrasive (Norton was one of the pioneers of such abrasives), such that the "highest" particles tend to break down and leave a somewhat smoother sharpening surface than the particle size suggests. That sort of thing can only modify the surface quality within a relatively narrow band (nothing can make a 100 um particle leave a clean edge for example), but it could explain the difference in this case.

Bottom line: As you say, the results are what matters. Things like abrasive particle size are a useful but imprecise guide to help us get to the results we want. Grit # is basically useless IMO unless you know what standard is being used (JIS, CAMI, FEPA, etc)