How to Sharpen Every Knife Grind: Whetstone, Diamond Plate, Strop and Rod

Different grinds want different sharpeners. Use a flat whetstone on a convex grind and you will slowly flatten the curve. Use a strop on a Scandi and you will round the crisp bevel that makes it cut wood so well. This guide walks each grind, the right tool, and the exact angle and technique.

Before you start: the four sharpening tools

1. Whetstone (waterstone or oilstone) — flat abrasive block, usually 400/1000, 1000/6000 or 3000/8000 grit. The workhorse. Best for flat, hollow, saber, Scandi and chisel grinds.
2. Diamond plate (or diamond stone) — flat plate coated in industrial diamond. Cuts every steel including M390, S30V and MagnaCut where regular stones struggle. Never dishes.
3. Ceramic rod / crock stick — round or triangular. For quick touch-ups, serrations, and maintenance between real sharpenings.
4. Leather strop with compound — a strip of leather (usually mounted on wood) loaded with polishing compound. The only correct tool for convex grinds, and the finishing step for every other grind.

Two universal rules:

• Match the existing bevel. Whatever angle the blade was ground at, that is the angle you sharpen at. Feel the bevel flat on the stone before you start.
• Sharpen until you raise a burr on the whole edge, then flip and match. A burr — a tiny wire of steel folded over the edge — is proof you have sharpened all the way to the apex.

Flat and saber grinds — whetstone

Most kitchen chef's knives and many bushcraft/military knives.

1. Soak a water stone for 10 minutes (skip for oil or diamond stones).
2. Hold the edge bevel flat on the stone. Most kitchen knives are 15–17° per side; most outdoor knives are 20°. If the factory bevel is visible, match it.
3. Push the edge forward across the stone like you are trying to shave a thin slice off the stone. Keep the pressure light and the angle steady.
4. Do 8–10 strokes per side, alternating, until you raise a burr along the entire edge.
5. Move to the fine side (3000–8000). Same motion, half the pressure.
6. Finish on a loaded strop — 20–30 alternating trailing strokes, edge trailing.

Hollow grind — whetstone or fine rod

Same technique as flat grinds. The hollow itself is not touched — you only sharpen the small edge bevel.

• If the knife came from Buck, Kershaw, or a similar factory hollow, the bevel is usually 20° per side.
• Use a fine ceramic rod (Sharpmaker, Lansky, DMT) between real sharpenings — hollow grinds respond very well to a few strokes on a fine rod.

Scandi grind — flat whetstone, no jigs needed

The Scandi is the easiest grind to sharpen freehand because the bevel is the angle.

1. Lay the entire flat bevel on the stone. You will feel it lock in — both the top and bottom of the bevel touching.
2. Push forward, edge-first, keeping that whole-bevel contact. Do not lift the spine.
3. Alternate sides every few strokes.
4. When you raise a burr edge-to-edge, move to a finer grit and repeat.
5. Strop lightly to remove the burr — but only a few passes, so you do not round the bevel into a micro-convex.

Common mistake: adding a secondary edge bevel to a Scandi. Do not. The whole point of the grind is the single flat bevel.

Convex grind — leather strop (this is the important one)

Do not put a convex grind on a flat whetstone. A flat stone only touches the middle of the curve and will slowly grind two flats into the blade, ruining the geometry.

Correct tools:

• Leather strop with green compound (chromium oxide) for daily maintenance.
• Mouse pad + wet/dry sandpaper (400 → 1000 → 2000) for actual sharpening, or a slack-belt sander for shop use.

Mouse-pad method:

1. Lay a sheet of 400-grit wet/dry sandpaper on a mouse pad or folded towel. The soft backing lets the paper flex around the convex curve.
2. Edge-trailing strokes — drag the blade spine-first across the paper, like you are wiping paint off it. The soft backing wraps the abrasive around the convex.
3. Alternate sides. Raise a burr, move to 1000, then 2000.
4. Finish on the loaded leather strop — 30–50 edge-trailing strokes per side.

Between sharpenings, 10 strop strokes per side keeps a convex knife shaving sharp for weeks.

Chisel grind — whetstone (mostly one side)

1. Lay the ground side flat on the stone. Because it is flat, you can rest the whole bevel — no angle guessing.
2. Push-cut strokes until you raise a burr on the flat/back side.
3. Flip the knife. Lay the flat back side dead flat on the stone. Two or three very light strokes to shear off the burr. Do not add a bevel on the flat side — it stops being a chisel.
4. Strop the ground side only.

Serrated edges — round ceramic rod or tapered diamond file

Serrations look intimidating but are the easiest edge to touch up if you have the right tool.

1. Use a tapered round diamond file or a fine ceramic rod that fits inside the smallest scallop. Spyderco Sharpmaker triangle rods work well.
2. From the ground side of each tooth (usually one side is bevelled, the other is flat), push the rod through each scallop at the factory angle — usually 10–15°.
3. Do 3–5 strokes per scallop, working down the blade. Keep the count consistent.
4. Flip the blade and lay the flat side on a flat stone. One or two very light strokes to knock the burr off. Do not grind the flat side — it destroys the serration pattern.

The tips of the teeth (the "points") also wear down. Very lightly hit them on a flat stone at a low angle — enough to renew the point, not enough to shorten the tooth.

Combo edge (part-serrated)

Sharpen the plain half as a normal edge (whetstone, matching bevel). Sharpen the serrated half as above. Do not try to run the whole knife across one stone.

Fixing chips and rolls

If the edge has a chip, drop a grit level (start on a 200–400 diamond plate) and grind the whole edge down until the chip disappears. Then rebuild the bevel normally through 1000, finer, strop. Skipping this step and going straight to a fine stone is why people spend an hour sharpening and still cannot cut paper.

Sharpeners to buy on Amazon

Pick one from each category and you can sharpen any knife on Earth.

• A good dual-grit whetstone (1000/6000):
  • Whetstone knife sharpening stone 1000/6000 grit
• A diamond plate for hard steels (M390, S30V, MagnaCut):
  • DMT Diamond bench stone coarse/fine
• A ceramic rod system for maintenance and serrations:
  • Spyderco Sharpmaker 204MF
• A leather strop with green compound (mandatory for convex):
  • Leather strop with green polishing compound
• A tapered diamond file for serrations:
  • Tapered diamond sharpening rod for serrations
• A guided system if you do not want to freehand:
  • Lansky Deluxe 5-stone system
  • Work Sharp Precision Adjust

Quick chart: grind → tool

Related on Wild10

• Knife steel types
• Knife grinds explained