Quote Originally Posted by blaireau View Post
Grit is a measure of the particles that go through a certain size mesh and as such can be related to a particle size. The relationship can be derived from the chart I published in my first post to this thread above. It is a logarithmic power law equation and when expressed as such it has a better than 99% fit. It isn't simple but it can be understood. As you can see, though many have asserted that a Belgian Blue has a 4000 grit and a Coticule an 8000 grit, the actual grit that relates to these stones is more like 1200 to 1800.
Well yes, I've been saying that for quite some time now, glad someone confirms it.
Of course, I completely understand why they can't be sold as such, and they really shouldn't, but for understanding how they work it's good to realize they don't have the particle size of the fine synthetic hones, such as produced by Naniwa, Norton, Shapton, DMT and others.
The Belgian hones don't derive their brilliance from a high grit rate, and that's what makes them so unique. Apart from my disorienting mumblings about the math of grits and particle sizes, I consider the real highlight of my first post to be in the drawing. It shows that , in theory, and without considering plastic deformation, a large round garnet-like particle can create a keener edge than a considerably smaller spike-like particle. It also shows how a fast (hence deep cutting) spike-like particle renders an edge into a wire edge when the scratches of both sides start meeting each other at the very edge.

I haven't made a drawing of two sizes of round garnet-like particles, but I would like to formulate a daring hypothesis:

The Belgian Blue Whetstone has larger garnets than the Coticule.
IF those larger garnets have more facets, than those facets will be obtuser than the Coticule's.
For that they will cut smoother curves.
For that they will exert less PSI on the steel, leaving a shallower scratch pattern.
The Blue's slowness in relation to a Coticule seems to confirm this.
IF all that's true, and IF the principles that my drawing shows are sound;
then the Blue will allow a keener edge than the Coticule.

I have already testified on another thread about the Blue with slurry leaving a keener edge than the Coticule with slurry. So have Josh Earl and David Polan (Heavydutysg135) testified before me. What about the Blue with water, then? I've always considered it too slow to give it a serious try. But aren't some top dollar Japanese Natural hones not considered too slow as well for use too early in a progression? What if I dismissed the Blue with water, simply because I failed to realize I was using it before its time?

IF SO, an ideal progression might be:
1. Coticule with slurry till bevel is set and keennes levels off.
2. Belgian Blue with slurry to refine the edge till keennes level off.
3. Coticule with water for 100 laps.
4. Blue with water for 100 laps.

High time I got away from the laptop and started honing...
I'll keep you guys posted.

Bart.