BESS Score to Edge Width correlation in the lower BESS scale

[EOU]

Tell me about it Mark.  There are some straight razor guys out there using our products. They just won't tell us how they are doing and we are curious. Some say that they can sharpen as sharp or sharper than a DE blade and others in the business tell us they're dreaming. It would just be nice to know. We remain curious but hopeful...not so much.

[KnifeGrinders]

Here are the BESS scores for the vintage razor with links to videos:
BESS 17 yesterday, I did not test today before I started shaving.
BESS 41 after shaving 50% of the face, I chickened out and finished with a DE safety razor    (video: vintage after shave ) 
BESS 33 after stropping 5 times each side on Kanayama Cordovan Strop (Video: vintage after stop )
BESS 19 after stropping 10 times each side on balsa with 0.5 micron chromium oxide and finally finished on a Kanayama Cordovan Strop 5 times each side. (Video: final stropping )

Please be advised that this is only my trial and error (or trial and success) for this razor and might or might not work for other razors.

Cheers
HTR

By BESS-certified test line on PT50A, HTR's straight razor shows under 20 nm edge radius after stropping - this is better than the Gillette razor manufacturing target of 200-300 Angstroms (20-30nm).
BTW the reason DE razors score around 40-50 BESS is the additional coating on the edge the manufacturers apply for a smoother shaving feel.

[EOU]

Yes, little doubt about it KG. HTR has got it going with straight razors. There just isn't much room left for improvement.

[KnifeGrinders]

In his SEM study The Honing Progression Todd Simpson gives edge apex in microns for edges set edge-leading on bench stones of progressively finer grits. The edge set on Shapton JIS #4000 has apex width of 0.3 micron


Edge-on view image after Shapton 4k, showing an apex width in the range of 0.3 microns.

When I was checking accuracy of our computer software to set grinding angle, I took BESS scores of knives ground edge-leading on the Tormek Japanese wheel #4000 - on this wheel knives get sharpness averaging 152 BESS. As we know, the sharpness score of 50 BESS indicates 0.1 micron apex, and the sharpness tester reading of 152 BESS tells us of 0.3 micron apex width, which is consistent with the scanning electron microscopy in the Todd's study.

Details follow.
Global kitchen knives ground at 14 dps, edge set on Tormek-8 on a CBN wheel #1000 diameter 254.2 mm - a tiny but visible burr scoring near 300 BESS.
Edge-leading deburring on a Tormek-7 machine on an SJ wheel #4000 diameter 240.7 mm scores:

Tormek SJ wheel #4000, grinding at the exact edge angle = 150 BESS (knife 1) and 154 BESS (knife 2).

Tormek SJ wheel #4000 at -0.1 degree less than the edge angle, i.e. at 13.9 dps = 168 BESS (knife 3).

Tormek SJ wheel #4000 at -0.2 degree less than the edge angle, i.e. at 13.8 dps (knife 4):
           1 pass each side = 209 BESS,
           2 passes each side = 149 BESS,
           3 passes each side = 135 BESS.
I could see how with each pass the band of polished metal was spreading from the edge shoulder towards the apex till reached it on the 3rd pass.

Tormek SJ wheel #4000 at -0.3 degree less than the edge angle (knife 5) = 250-330 BESS; after 2 alternating passes a band of polished metal was clearly visible on the edge bevel near the shoulder not reaching the apex.

(In our estimate, real life accuracy of our computer software, given the manual setup, is 0.1 degree.)