Maximum-force belt work. The .065" standard gauge is not the rigid heavy-belt blade; that is the .083" knives' role. The grind helps in dense material; it does not add spine.
General cutting where nothing is dense. On ordinary stock the relief buys nothing and a flat blade (60630) holds a tougher edge.
Prying, scraping, or striking — it is a wood-handled cutting edge, not a tool for abuse.
Sheet flooring over a subfloor that must survive — the 67090 hook knife exists for that captured-throat cut.
Throwaway-blade jobsite cutting — abrasive board and cardboard eat a maintained edge; use a utility blade there.
Compressible materials part under a long pulling stroke, not under downward pressure — lead with the draw and let the edge shear. Keep the stroke continuous through the depth. The relief helps most where the blade is buried, so travel through the whole thickness in one unbroken pass instead of stalling mid-cut where the cheeks can regain their grip. Respect the grind when you sharpen. A hollow-ground edge loses its geometry if it is honed flat on a bench stone; hold the factory angle, take light passes, strop the wire edge away, and reserve heavy grinding for rare occasions. Keep it, don't consume it. This is hardened high-carbon steel that takes a keen edge from a stone and asks only for a dry wipe after wet work — the maintain contract every fixed blade in this wing is sold on.
Asked at the counter
BUYER QUESTIONS ANSWERED BEFORE THE CART, NOT AFTER THE RETURN
Why hollow ground instead of flat?
Because dense foam clamps a blade's sides. Relieving the faces behind the edge takes steel out of that grip, so the knife slides through firm foam and deep rubber a flat blade fights.
Is the 60750 different from the 60720?
Not on anything documented — same blade, same grind, same claim. Only the BG works-code differs, and its meaning isn't in the record; decide on price or availability, not performance (§5).
When do I pick this over the flat 60630?
For firm, dense foam and deep rubber. For ordinary cutting the flat 60630 holds a tougher edge and is the better default.
Thin foam or thick?
Thick, firm bun within its six-inch depth. Thin stock suits the 4" hollow knives; very deep foam moves to the eight-inch knives.
Sharpening?
Keep the factory bevel; don't flatten the hollow on a bench stone. Light honing, frequent stropping.
Rust?
It is high-carbon steel — keep it honed and wipe it dry after wet work. Maintained, not fed.
