Michael Todrin
Had some time today over lunch to prepare a few chisels and chop some mortises.

Mortises were all 1.25"x1.25x 1" deep in a black walnut scrap. The mortising was done neither with great delicacy nor with excessive force. Probably a 6.5/10 on the continuum between the two.

Back of chisel was observed before and after testing with cheap microscope to look for chipping and rolling after chopping.

Chisel 1: Contemporary Stanley sweetheart 1" about 30 degrees. The prep was 1200 ez-lap, spyederco medium, 1 micron diamond on corian. 5 seconds on 4" drill mounted buffer with Mothers Mag polish.

Chisel 2: Same as above but 1.25"about 30 degrees. Same as above but no
unicorning.

Chisel 2a: Same chisel and prep as #2 above but with 40 degree micro-bevel.

Chisel 3: 1.25 Stanley with resin handle about 20 degrees. EZ lap, then buffing wheel.

All chisels shaved hair effortlessly before chopping and pared end grain pine cleanly leaving the nice waxy looking finish.

After mortising tests:

End grain paring:
Chisel 1: No visible difference in shaving quality or perceived difficulty.
Chisel 2: Significant degrade in shaving, could not cut a clean shaving.
Chisel 2a: No change
Chisel 3: More resistance but still clean shaving.

Shaving hair:
1: Effortless and comprehensive shaving
2: Still shaved a little but more effort and some missed hair
2a: Effortless and comprehensive
3: Still shaved but more effort and missed hair

Microscope:
1, 2a and 3 had some visible wear while 2 had significantly more.

Conclusions:

It appears that the unicorn bevel confers protection to an edge without a degrade in sharpness or perceived ease of cutting. I am not certain it has advantages over a flat secondary bevel in terms of performance. This will need to be looked into further. It was interesting that with relatively minimal prep you could still have a chisel (3) at least at parity with a more thorough flat bevel preparation(2). It appears that a low primary bevel and minimal preparation give a nice performance with very little difficulty on a $12 Borg chisel.

Further Questions:

What is the effect of different bevel angles on performance of the unicorn profile? How low can you go? What is the difference in longevity between a rounded and flat micro-beveled portion?