The Razor IV
The grinding wheels
The cutting stones have diameters of 110-120 mm, 140-150 mm, and 170-180 mm for 3/8", 4/8", and 5/8" blades, respectively. Their function is to create the straight edge, the back, and parallel back-edges. The pre-grinders have diameters of 75-80 mm, 95-100 mm, and 105-110 mm, respectively. Their function is to create the concave thinning of the blade between the belly and the edge. This represents the � hollow grind phase. The post-grinders have diameters of 50-55 mm, 60-65 mm, and 75-80 mm, respectively. Their function is to strengthen the edge and the thin part directly above it, and to creat the belly. The hollow grinders have diameters of 26-30 mm; 32-35 mm; and 36-41 mm, respectively, and they have a half round profile. Their function is to dig into the blade. The blade is put on the half round profile, in the length direction of the blade, about 2/3 next to the back.
Rule: the position of the sole determines the grade of hollow grind (1/4, �, � or 1/1, for positions directly above the edge to halfway towards the back, respectively - of course, between sole and edge there is always the wall).
After using the cutting stone to create the edge, the edge is honed under a direction of 45 degrees, to strengthen the edge and prevent any further forming of burr. The 45 degree angle is reset later at the sharpening hone.