Skip to main content
Abrasives and belt grinding in a working knife shop

Abrasives

Grinding & Sharpening CPM S90V

Surviving 9% vanadium: grind S90V annealed with fresh ceramics, use feather pressure and constant dunks once hard, and sharpen with diamond or CBN stones.

1 min readWritten by Rich LinvilleFree to read

S90V is the steel that teaches makers what vanadium carbide really means: nine percent of the bar is particles harder than most of your abrasives. Every hour the edge lasts in cardboard was pre-paid at the grinder and the bench. Here is how to pay efficiently.

Plain utility knife lying on a leather pad beside cut sheets and strips of corrugated cardboard on a dark shop bench.

On the 2×72

Premium ceramic belts, replaced early and often — S90V kills the cutting edge of a ceramic faster than any steel on this site, and a half-worn belt on this steel is a heat gun. Hog everything possible in the annealed state (profile, bevels to 80-90%, drilling — carbide bits live longer); after heat treat at 59-61 HRC, sharp 120-grit ceramics with feather pressure and constant dunking. Finishing: structured abrasives, low expectations, and acceptance that hand-sanding S90V is a hobby for people who hate themselves — machine-finish this steel.

Fresh red-brown abrasive belt strip beside a worn, greyed strip with flattened grain, shot low across a dark bench.

At the Bench

Diamond or CBN, mandatory — not preferred, mandatory. Conventional stones burnish the matrix and leave the carbides standing proud: the edge feels sharp-ish and performs dull. A coarse-medium-fine diamond progression plus diamond-emulsion strop delivers the edge the spec sheet promised; angles 18-20 dps. Sell every S90V blade with the diamond conversation, or field the ‘won’t sharpen’ email later — the physics live in the sharpening guide and the microbevel guide (a microbevel is extra useful here: touch-ups without fighting the full bevel).

Three diamond sharpening plates in black holders beside a wooden paddle strop on a rubber mat, on a dark shop bench.

The Budget

Double the belts, double the bench time of M390 — which was already half again a normal stainless. Quote build hours accordingly; S90V flagships are priced like flagships for shop-floor reasons, not marketing ones.

Five abrasive belts hang in loops from wall pegs above a diamond plate and a knife blank on a padded wooden tray.

Keep reading

Read these related guides

Three more from the same bench.

More in this topic

Same bench

Put the reference to work

I machine the parts, hand-assemble, track and test Torus grinders in Sterling, Illinois. Most orders ship in seven to ten business days from time of order.

See the whole shop
  • Classic aluminum 2x72 grinder, side view with flat-platen tool arm and yellow Safety Rules label, on black with a purple glow

    Torus 2×72 Classic Aluminum Belt Grinder

    Prior-design aluminum chassis, 90-degree tilt and 1.5-inch tooling arms.

    Starts at$995View

One-man shop

Still stuck? Ask me.

I answer my own email. Tell me the steel, the machine and what it is doing, and I will tell you what I would try next.

Ask Rich a questionBuild your Nova