Quote Originally Posted by mparker762 View Post
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.
Cutting - or better: chopping - a hair: is forcing a steel wedge in between the keratin cells of the hair. As we already discussed, the width of the tip is very important for penetrating the outer cells. But also the width of the steel that follows the very apex of the cutting bevel is important. The greater the bevel angle, the faster the bevel beefs up. That will have an effect on how easy the wedge cleaves the cells.

I believe, the smaller the bevel angle, the easier is will cut, but at a certain point, the long and thin bevel becomes too weak, so a compromise needs to be made.
I looks like that compromise centers around 17 degrees.

I also think that an edge with of 0.3 micron is much keener than an edge width of 0.4 micron. It might be a small difference to grasp, because we are not accustomed with dealing dimensions that small, but for severing organic structures, 0.3 is 25% keener than 0.4
I am adding this, because I think that having a keener edge width at the very tip can to some extent make up for having a bigger bevel angle.

Bart.