According to the instruction sheet in my Honemasters, you clamp the top of the knife blade in the Honemaster and use that to control to the angle as you pass the blade over the sharpening stone. Allowing the edge of the blade and the side of the Honemaster to both touch the surface of the stone should give you the same angle every pass. These look to be the forerunners of today's "Lansky" type sharpening systems where the blade is still clamped into the guides. The difference is today's systems have rods for the stones that pass through the guides and you work the stones, not the knife.