This is the sharpening stone we make for sharpening the steel blade. It is a 150mm/6", 120 grit green silica carbide stone and it loves to cut into very hard materials like high speed steel. Also, when the grains of the stone break, they break into a new sharp point, much like a fine diamond file.
Sharpening the steel blade is done just like the Ruby Stones, except you use our sharpening stone instead of a diamond file, under running water, and you sharpen all four sides until the blade's sharpness is restored. It can be sharpened an infinite number of times, we are always amazed when we sell replacement steel blades, there rarely is a reason to replace them if they are maintained correctly.
It is best used in a circular honing pattern, rather than a back and forth pattern, which will put a sharper edge on the steel blade, just make sure you keep the stone very flat on the steel blade, no wobbling allowed.
It is a good habit to re-dress the steel blade EVERY time you use it, kind of like a barber sharpening his razor on the chair belt. Why? Because it will then cut much faster and cleaner and makes the steel blade a pleasure to use. If you use the steel blade this way, it will never wear out, will never need replacement.
