Took several new blades, measured the width from edge-to edge of each with a micrometer (one used in heart valve production), and viewed each under a 100-power microscope. I am not a metallurgist, nor do I have access to the kind of equipment that can quantify the edge smoothness, or super-magnify, etc. Measurements stated are the measurements on each end of the blade, to ten-thousandths of an inch. Multiple measurements were made. Smoothness is a qualitative statement, viewing the cutting edge at various angles. Regretfully, I didn't have a Personna Red with me, nor did have anything to take the waxy coating off of the Feather for viewing.
Shark Super Chrome- .8636-9"(.0003 variation is within the expected range of measurement error). This blade had the smoothest edges(visually), and the corners were the most smoothly-rounded in a constant radius and bevel. On repeated measurements, the Shark had the second-most-consistent width measurements on each end, ie. no taper or "un-parallelness".
Gillette 7 O'Clock Yellow- .8651" Second smoothest edge visually, most consistent measurements (no taper).
Super Iridium- .8643-46" Third smoothest, but very close to the Gillette.
Feather- .8656-64" This was both the widest blade and the one with the greatest variation in end-to-end width.Coating obscured the edge for viewing, and I didn't have the means to "wash" it.
Astra .8654-6" Second widest blades. Smooth edge, but it had obvious, tiny "nicks" along its edge.
Crystals(platinum super)- .8625" Narrowest blades. Very rough, saw-like edge.
Widest to Narrowest:
Feather .8656-64"
Astra .8654-56"
Gillette Yellow .8651"
Iridium .8643-6"
Shark .8636-9"
Crystal .8625"
FWIW, my favorites are the Gillette Yellow and the Iridiums. I am still trying to make peace with the Feathers and the Sharks.
Shark Super Chrome- .8636-9"(.0003 variation is within the expected range of measurement error). This blade had the smoothest edges(visually), and the corners were the most smoothly-rounded in a constant radius and bevel. On repeated measurements, the Shark had the second-most-consistent width measurements on each end, ie. no taper or "un-parallelness".
Gillette 7 O'Clock Yellow- .8651" Second smoothest edge visually, most consistent measurements (no taper).
Super Iridium- .8643-46" Third smoothest, but very close to the Gillette.
Feather- .8656-64" This was both the widest blade and the one with the greatest variation in end-to-end width.Coating obscured the edge for viewing, and I didn't have the means to "wash" it.
Astra .8654-6" Second widest blades. Smooth edge, but it had obvious, tiny "nicks" along its edge.
Crystals(platinum super)- .8625" Narrowest blades. Very rough, saw-like edge.
Widest to Narrowest:
Feather .8656-64"
Astra .8654-56"
Gillette Yellow .8651"
Iridium .8643-6"
Shark .8636-9"
Crystal .8625"
FWIW, my favorites are the Gillette Yellow and the Iridiums. I am still trying to make peace with the Feathers and the Sharks.
