Thread: My razor is too sharp???? I like a duller edge??

Originally Posted by Seraphim

Honing at 48 degrees?

That' s a cakewalk compared to what staright users must contend with (as you well know).

Yes, he mentions that in his paper.

pg 14

The effects of changing the 2β edge angle are illustrated by comparing the blade of Fig. 17 which had 2β = 70o to Fig. 16 where 2β = 50o. ... The larger angle produced noticeably more breakout along the edge, an effect which was confirmed to increase as the angle was increased over the 3 values studied, 50, 60 and 70o.

and pg 21

...however, sharpening a blade with the 2β edge angle of the razor blades, 17o, is more difficult than a blade with the 2β edge angle of 40o.

Which brings up an interesting question: why is the standard honing angle for straight razors is 17 degrees and not 20 or 30 or 40 like knives? FWIW both the Gillette blades he tested and the straight razor he tested had 17 degree honing angles.

The answer for straight razors may simply be the weight of such a heavy spine, or maybe the necessity for shaving with a lower angle and the wide spine would get in the way. But I'm not sure that either explanation is sufficient. Framebacks solve the weight issue (and given the popularity of the big 8/8 wedges clearly weight wasn't *that* much of a problem), and a 40 degree honing angle is only 20 degrees either side which doesn't seem unworkable given that 25-30 degrees is a common angle for shaving. So why 17 degrees? We've seen that going much lower than that makes for an edge that is simply too weak to hold up, so that explains why it isn't lower, but why isn't the standard angle much higher? And Gillette certainly didn't have to worry about weight or spine thickness, yet they went with the same angle. The Feather has a final bevel angle of 25 degrees, yet their primary bevel is I believe right around 17 degrees (I can't find Zowada's post where he gives the angles for the various bevels on the Feather, so if somebody runs across that post please feel free to correct me).

Originally Posted by hardheart

Yeah, the depth of the sawtooth effect the abrasive will have on the edge is greatly increased as the angle is lowered, plus worrying about microchipping. Finish on the bevel sides should be pretty consistent, I would expect.

Neither Verhoeven's photos nor the photos from other guy a few months ago that posted SEM photos of his own edges showed any evidence of sawteeth at 3000x. Verhoeven's photos show sawteeth from honing at coarser grits, but not once you get up to the sorts of abrasives that we use - once the depth of the scratch marks is lower than the edge width then they may as well be farm furrows running off the cliffs of Dover.