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Abrasives and belt grinding in a working knife shop

Abrasives

Grinding and Sharpening CPM S30V: Belt Recommendations & Technique

CPM S30V is demanding to grind: ceramic or Trizact belts, high speed with light passes, frequent cleaning, a grit progression and on-grinder sharpening.

1 min readWritten by Rich LinvilleFree to read

CPM S30V is one of the more demanding steels in this database to grind, sitting alongside CPM 20CV and CPM M4 near the top of the “hardest to work” list. Its heavy vanadium carbide load, the same feature that gives it top-tier edge retention, means belts load and dull faster than on tougher, easier-grinding steels like MagnaCut or Elmax.

Worn abrasive belt draped over a wooden bench rail, with a silvery patch of metal loading on the grit

Belt Selection

Ceramic belts are the standard recommendation for CPM S30V, the same guidance that applies to CPM 20CV. Structured abrasive belts, such as 3M Trizact or Norton Norzon, run cooler and last noticeably longer than standard aluminum oxide belts on this steel, and are worth the extra cost for anyone grinding S30V regularly.

Strip of structured abrasive with fine repeating raised grit, one corner turned up to show the backing, beside a steel block

Grit Progression

StageGrit
Profiling / heavy stock removal80
Bevel refinement180
Pre-finishA45 structured abrasive
FinishHand rub or polish

Technique

Run higher belt speed with light, controlled passes and dress the belt frequently as it loads. A coolant mister is worth running throughout, both to protect the temper and to extend belt life on this carbide-heavy steel.

Bracket-mounted segmented coolant nozzle aimed at a vertical belt above a steel work rest on a switched-off grinder

Sharpening

CPM S30V can be sharpened effectively right on the belt grinder itself, not just with stones off the machine. A common shop method uses fresh, soft-backed silicon carbide belts in a light progression, such as 400 grit, then 800 or 1200 grit, finishing on a plain felt belt charged with white buffing compound for a polished, keen edge. For stone sharpening off the grinder, S30V responds well to a polished-edge approach, finishing on a fine aluminum oxide stone or belt before stropping with a fine compound.

Cream felt belt loop with a thin white compound smear lying beside two flat dark fine abrasive belts on a steel bench

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