Sharpening & Edge Maintenance

In simple terms

Sharpening means grinding a new, clean edge where two bevels meet. Honing and stropping keep that edge straight and polished between sharpenings. Most dull knives just need a few minutes of honing; only a truly worn or damaged edge needs real sharpening.

Gary’s bench

Sharpening is one of Gary’s long-time passions. His campsite workshop doubles as a ham shack and a sharpening bench. He’s taught all three of his grandsons to sharpen, letting them try everything from a guided system to the belt sharpener.

• Guided systems (his first choice): KME, Wicked Edge, Edge Pro and Lansky. The clamp or guide holds the angle for you, so you get repeatable, precise results.
• Quick maintenance: ceramic crock sticks and a Spyderco-style V-rod sharpener.
• Powered: a Work Sharp Ken Onion with the blade-grinder attachment, used for quick work and reshaping, not as the main method.
• Freehand stones: waterstones up to 12,000 grit, kept in a soaking bath, with a flattening plate to keep them true.
• Finishing: leather strops (coarse and fine), diamond emulsions down to very fine microns, and green, white, brown and gold rouges.
• Measuring: an angle cube (digital angle gauge) to check and set angles exactly.
• Woodworking: Veritas honing jigs for chisels and plane blades.

The basics: apex, burr, hone, strop

• Apex: the very line where the two bevels meet. Sharp means a clean, unbroken apex.
• Burr: a tiny wire of metal that forms on the opposite side when you’ve ground all the way to the apex. Feel for it with a fingertip, across the edge, never along it. No burr means you’re not done with that grit.
• Work through the grits: coarse to set the bevel, medium to refine, fine to polish. Don’t skip big jumps.
• Strop last: a few light, edge-trailing passes on leather (with or without compound) remove the last of the burr and polish the apex.
• Toothy or polished? A slightly coarser edge bites into rope and tomato skins. A polished edge push-cuts and shaves cleanly. Match the finish to the job.

What angle?

Angles below are per side. The total edge angle is double. Lower is sharper but more delicate; higher is tougher.

Chisels and plane blades are usually set as one total bevel, often 25° with a slightly steeper micro-bevel on the very edge. When in doubt, match the angle the knife came with. An angle cube or marker trick (colour the bevel with a felt marker and see where the stone removes it) tells you where you are.

Grit progression, roughly

• Repair or reprofile: 100–220 grit. Only for chips, broken tips or changing the angle.
• Set the edge: 300–600 grit.
• Refine: 1,000–3,000 grit. Plenty for most working knives.
• Polish: 5,000–12,000 grit stones, then strop.
• Mirror: fine diamond emulsions or compounds on a strop or hard backing.

Grit numbers aren’t the same between systems (JIS for Japanese stones, FEPA “P” grades for sandpaper, microns for films and diamond), so use these as a guide only.

Sandpaper, serrations and other tricks

• Sandpaper on glass: wet-or-dry paper on a sheet of glass or a granite tile is a cheap, precise sharpening system, and doesn’t freeze in a cold shop or truck like soaked stones can. Gary keeps paper up to 5,000 grit.
• Serrated edges: use a tapered diamond rod on the bevelled side only, matching each scallop, a few light strokes each. Then one light pass on the flat side to remove the burr.
• Honing rods: a ceramic rod or smooth steel straightens a rolled edge in seconds. It doesn’t remove much metal, so it maintains rather than sharpens.
• In a pinch: the rough, unglazed ring on the bottom of a coffee mug works like a fine ceramic hone. A smooth, flat river stone or the top edge of a car window can rescue a dull blade on the road. Finish by stropping on a leather belt, denim or cardboard.

Strops and compounds

A strop is any smooth, flat backing (leather, balsa or hard maple) charged with a fine abrasive. Leather gives slightly, which can round the edge if you press hard. Hard wood like polished maple stays flat for a crisper edge with diamond paste or emulsion.

• Coloured rouges and compounds vary by brand. Green chromium oxide is a common fine polish, but “green” from one maker isn’t the same grade as another’s. Check the maker’s micron rating.
• Always strop edge-trailing (spine first). Light pressure, a few passes per side.
• Keep each strop for one compound, so coarse grit doesn’t contaminate a fine strop.

Straight razors

Frank, Gary’s old neighbour, shaved his entire head with a straight razor without a mirror. A razor is sharpened on very fine stones with the spine resting on the stone (which sets the angle), then stropped on linen and leather before every shave. It’s the most demanding edge there is. Start with a professionally honed razor and learn stropping first.

Tools beyond knives

• Axes: a file and a puck-style axe stone, or a slow wet grinder. Keep a convex edge for toughness.
• Mower blades and shovels: a file or slow grinder. They need a working edge, not a razor.
• Chisels and plane blades: a honing jig (Gary uses Veritas) on stones or sandpaper, with the back flattened first.
• Avoid fast dry grinders on knives. The heat can ruin the steel’s temper in seconds. If it turns blue, it’s been overheated.

Testing and safety

• Paper test: a sharp edge slices printer paper cleanly without tearing.
• Tomato test: it should bite the skin with no sawing.
• Light test: look straight down at the edge under a light. Shiny spots are dull or rolled.
• A sharp knife is safer than a dull one, because it doesn’t slip. But wear a cut-resistant glove on your holding hand while you learn.

Keep reading

• Blades, Multi-Tools & Edge Tools · Bushcraft, Fieldcraft & Navigation · Tools