This is a #9 size Belgian coticule bout (“bout” = polygon), bonded to slate. One axis has been aligned to a ~6.5’Ø form, with a ~25’Ø shape affected across its the axis which is 90° to the ~6.5’Ø-shaped axis.
There is a free included slurry/rubbing stone, which has been shaped concave to the bench stone. See the images for more information.
For the primary shape of your bevel, face your razor’s spine-to-edge axis toward the long facet of this stone, where it will cut in a nice and concave bevel. There is a 25’Ø axis *across* the stone’s ~0-63mm “width”, so as you rub your razor down the long axis of this stone, try to vary where you work upon the bevel, or move the contact patch across the bevel like a circuit. I detail these concepts below;
To further refine your bevel’s concave shape after completely overtaking the incumbent bevel with this stone’s shortest 6.5’Ø effective diameter, reorient your razor on the stone to align the heel of the razor to the second-longest facet (~86mm) which is ~45° to the stone’s “length” , and proceed to move across the stone keeping the heel moving parallel to that 86mm facets. I don’t know the exact effective diameter of such a maneuver, but I’ll guess it around a 5mØ. It would certainly be enough to finish a razor’s bevel with that shape, no question about it, but if you like you can always move on to a pasted strop or flat/hard/fine finisher for a three-stage compound bevel as mentioned in the old forbidden German grinders’ text from the 1840s. The idea of a pasted strop is that, being on a paddle or a hanging strop, that abrasive field is gently con*cave*, meaning that the lasssst little tip of the bevel is gently con*vex*…a conVEX tipped bevel that is otherwise as a whole profile decidedly conCAVE due to the prior work on the conVEX whetstone.
