Metallurgy Field Manual · Plate 07

The Edge Lab — honing vs. sharpening

A cross-section of a knife edge, magnified ~1000×. The steel narrows to a fine apex just a few microns wide — and everything below happens to that tiny tip: it can bend (honing fixes that) or actually wear away (only sharpening fixes that, at the cost of a little metal each time). Use the blade, then try honing it, and watch the apex.

CROSS-SECTION · MAG ×1000
100%
Cutting Sharpness
Aligned
0
Cuts
0
Hones
0
Sharpens
Blade
life

What's happening

This is a perfectly sharp, brand-new edge. The two ground faces meet at a crisp apex — that fine point is what does the cutting. Try using the knife and watch the apex closely.

Legend

A keen edge is a fine point. The sharper the apex, the smaller its radius — read sharpness straight off the shape of the nose.
Dashed centerline = the true edge axis. A rolled edge bends off it (a steel pushes it back); a worn edge rounds into a blunt nose on it (only sharpening fixes that).
Faint outline = the blade's original size. Sharpening grinds the edge back, so the steel only ever gets smaller — the bevel angle stays the same.