Since Iím trying to make these tests as objective as possible, Iíd like to describe my methods in enough detail to allow others to check my results. Below are brief comments with links to more complete descriptions.
The Blades Being Tested
Iím testing several A2 blades by current makers, carbon steel blades both old and new, and a couple of blades made from more exotic steels not commonly used for plane blades.
After experimenting with different honing abrasives and testing the sharpness of the edges they produce, I am now using ¼ micron diamond paste to hone all of the blades. The bevel angle is precisely controlled by use of a honing jig, and a small back bevel is used to make sure the cutting edge is formed by the intersection of two finely honed surfaces.
Infill planes are used for all of the planing, even for the blades designed for Bailey-style planes.
For an inexpensive microscope the View Solutions GE-5 provides a good deal of magnifying power. To overcome its shallow depth of field Iíve mounted it in a carriage that allows for fine adjustment of the focus. Because the 9x auxiliary lens produces a shadow that makes the microscopeís built-in LEDs ineffective Iíve added four LEDs at angles that Iíve found to reveal the greatest amount of detail at the bladeís cutting edge.
This testing produces numbers that allow comparison of the results of blade tests done at different times.