Chapter 20 · Tools and knife
20.4 Sharpening
In this section (4)
A sharp knife is safer than a dull one: it cuts with less force and slips less.
What you need
The angle
The angle is measured on each side of the edge. Lower = sharper but more fragile; higher = tougher.
| Type of knife | Approximate angle per side |
|---|---|
| Kitchen | 15–18° |
| Pocket knife | 17–25° |
| Outdoor or survival knife | 25° or more (up to 35° for very rough work) |
What matters most is not the exact number but keeping the same angle on every pass. Trick: for about 20°, rest the edge at 90° on the stone, lower it halfway (45°), and then halfway again (about 22°).
Stone technique
- Prepare the stone. Wet it or oil it depending on its type and set it on a damp cloth so it doesn't slide.
- Mark the bevel with a permanent marker. That way you can see whether you're sharpening at the right angle: the ink should disappear evenly across the whole bevel. If it only wears off at the top, the angle is too low; if it only wears off at the edge, too high.
- Start on the coarse grit. Holding the angle steady, push the blade edge first, moving from the base to the tip in a single curved pass. Light, even pressure.
- Same number of passes per side (for example, 10 and 10).
- Look for the burr: a small rough ridge on the opposite side of the edge, which you feel by running your finger from the spine toward the edge (never along the edge). When it appears along the whole length, that side is done.
- Move to the fine grit and repeat with less pressure and alternating passes to remove the burr.
- Polish (optional) on leather, dragging spine first.
- Test it by cutting a sheet of paper: it should cut cleanly without tearing.
- Clean and dry the blade and the stone.
Without a stone
- The unglazed rim on the bottom of a ceramic mug or plate works as a fine stone.
- A smooth, fine-grained stone, wet, can restore an edge in the field. Keep the same angle and try a few passes first.
