Originally Posted by
Bart
I'm going to have to respectfully disagree on that one.
The sharpness of an edge is defined by the width of the bevel tip.
Every hone will remove steel, but at the same time, it will also abrade the bevel tip. The keener a bevel becomes, the weaker it's tip. At a certain point, the hone will start to abrade the tip as quickly as it removes steel from the faces of the bevel. At that point honing further on that hone has no purpose. Another hone, with gentler (read slower) cutting properties can refine the bevel tip further, till we hit the barrier on that one. There is no reason why 4K should be a limit. As a matter of fact, I can feel the difference in keenness very well during a shave, if I compare 5K edge, finished on a Coticule, with a 10K edge, finished on the same Coticule. The former pulls ATG, the latter doesn't.
If a bevel tip measures 0.5 micron, and you manage to reduce with 0.05 micron with an 8K hone, I'm pretty sure that makes a significant difference in the ability of that tip to sever hair. Because we are exactly in the critical range for severing hairs. But is a bevel tip of 1 micron is reduced with 0.05 micron with the same 8K hone, it will shave just as marginally (or not) as it did before. In the former case, the 8K has significantly added to the keennes of the edge. In the latter case, it just offered some polishing.
CrO on a strop, to answer Kristopher's original question, has the power to convex the bevel a bit, because there's always some cushion in the substrate that carries the paste. That diverts all abrasion to the tip. Secondly, the direction is away from the edge, introducing pastic flow as an aid in shaping that same tip.
Bart.