Grinding and Sharpening 15N20: Belt Recommendations & Technique

15N20 is a pleasure to grind and very easy to overheat, for the same reason: it is almost always sold thin. Stock in the 0.060 to 0.125 inch range has very little mass to absorb heat, so a bevel that would merely get warm in quarter-inch bar can go blue in seconds. Master that and the steel gives you almost nothing else to worry about — there are no coarse carbides to tear out, no diamond requirement, and no drama at the stones.

Grinding Thin Stock Without Cooking It

This is the whole skill with 15N20. Thin stock heats fast, and the closer you get to the edge the faster it goes. Three habits solve it: keep the blade moving across the full belt rather than dwelling, dip in water far more often than feels necessary, and use fresh sharp belts so the grit cuts instead of rubbing. Grinding annealed and heat treating afterwards removes most of the risk — and because 15N20’s heat treat is straightforward (1475–1500°F, fast oil, low temper), there is no reason not to.

Grinding Hardened 15N20

At 61 to 62 HRC, 15N20 is harder than most simple carbon steels ever get, but it grinds far more easily than that number suggests — there is no carbide volume to fight. The tempering temperature is the caution: at 300 to 350°F, the margin before you draw the temper is genuinely small. Slow the machine for finishing passes and treat any visible colour on the edge as a failed blade rather than a cosmetic problem.

Belt Progression

• Hogging (annealed): 36–60 grit ceramic — light pressure, and remember there is less material here than you are used to
• Bevel setting: 60–120 ceramic or zirconia
• Refinement: 220–400 — the fine grain takes a clean belt finish
• Finishing: Trizact or hand sanding — 15N20 hand-finishes beautifully and shows no tear-out

Full belt-selection logic in the Belt Buyer’s Guide.

Finishing Damascus That Contains 15N20

If your 15N20 is a layer in a pattern-welded billet rather than a monosteel blade, the grinding is the same but the finishing is not. The pattern only appears after etching, and etching reveals every scratch you left behind — so a damascus blade needs a genuinely clean hand-sanded finish, usually to 400 or 600 grit, before it ever goes in the ferric chloride. Sand in one consistent direction and inspect under raking light. Details in Etching Damascus.

Sharpening 15N20

Easy, and satisfying. With no alloy carbides to speak of, 15N20 cuts on any abrasive — aluminium-oxide stones, ceramics, belts, guided systems — and it takes a very keen apex that strops back readily. The high hardness works in your favour here: at 61 to 62 HRC the apex is stable enough to hold a thin, acute grind. Run 15–17° per side on kitchen blades and slicers, which is where this steel belongs. Full method in How to Sharpen a Knife. Nickel or not, wipe and oil after sharpening — this is not a stainless steel.

Sources

• Knife Steel Nerds — How to Heat Treat Nickel Knife Steels: 15N20, 8670 and L6
• Alpha Knife Supply — 15N20 technical data