The most interesting questions have turned out to be the hardest ones to answer. Here are some preliminary conclusions.
Ability to Take a Sharp Edge
All of the blades Iíve tested have been able to take extremely sharp edges, but producing a sharp edge on some of the blades is possible only with the right type of abrasive. The alloys containing significant amounts of carbide particles (the Holtey S53 blade, the Academy Saws M2 blade, and my CPM 3V blade) need to be honed with diamond or chromium oxide to reach their greatest level of sharpness. No amount of careful honing on a fine waterstone will bring these blades to the same sharpness that the waterstones will produce on high carbon steel or A2.
Best Abrasive for Each Blade
Fine diamond paste has produced the very sharpest edges Iíve tested on all of the blades. This level of sharpness is almost matched by chromium oxide on most of the blades and by 8000x waterstones on the high carbon steel and A2 blades. I would guess that finer waterstones would be able to produce edges as sharp as Iíve achieved using diamond on these blades, but I havenít tested any waterstones finer than 8000x.
Iíve done only a little testing of oilstones. A translucent Arkansas stone dating from the 1920s produced an edge less refined than I had expected and I stopped testing oilstones at that time.
The very best edge retention was found in the Academy Saws M2 blade and the CPM 3V blade. Any difference between these blades is smaller than my experimental error, so I consider them tied.
The Holtey S53 lost its initial sharpness somewhat faster, then remained at a reasonable ďworking sharpnessĒ for a considerable time.
The A2 blades retained their sharpness longer than the carbon steel blades. I havenít yet tested all of the blades or tried to find differences between A2 blades from different makers.
At this time Iím using a bevel with a total included angle of 34º, formed by a 31½º primary bevel and a back bevel of 2½º. The A2 blades show minor chips after planing cherry, so for harder woods a larger bevel angle may be needed.
The Academy Saws M2 blade and the CPM 3V blade resisted chipping at an angle of 32º and showed only the smallest amount of microchipping at 30º when planing cherry. The Hock A2 blade showed significant chipping at 32º and the other blades have not yet been tested at the more acute angles.