The stiffest heavy-belt cutting. At .065" it is the standard gauge; wide reinforced belt cover wants the .083" knives for rigidity, not the hollow grind for slide.
Bench detail and general straight cutting. Where the material isn't dense, a flat-ground blade (60630) is tougher at the edge and the grind buys nothing.
Scraping, prying, striking — a ground edge in a wooden handle.
Flooring over a subfloor that must survive — the captured-throat 67090 hook knife's job.
Generic disposable-blade work — abrasive board and cardboard dull a maintained edge fast; feed a utility blade for that.
Foam and soft goods are cut with a long drawn stroke that lets the edge do the work; pressing straight down compresses and tears. Let the grind carry the depth. The hollow grind's whole benefit shows in the buried part of the cut, so keep the blade moving through the full depth in one continuous draw rather than stopping and restarting where the cheeks can grab. Sharpen the hollow grind on its own terms. Honing a hollow-ground edge on a flat bench stone gradually flattens the relief and un-does the geometry; keep to the factory bevel with light, angle-matched honing, strop the burr off, and grind rarely. Maintain, don't feed. Hardened high-carbon steel, keen from a stone and wiped dry after wet work — the ownership contract of the whole heritage wing.
Asked at the counter
BUYER QUESTIONS ANSWERED BEFORE THE CART, NOT AFTER THE RETURN
What does "hollow ground" actually do?
It relieves the blade's faces behind the edge so less steel rides against the walls of a deep cut. In dense foam and thick rubber that means the blade slides instead of wedging, dragging, and tearing.
Is the 60720 different from the 60750?
Not on anything Hyde documents — identical blade, grind, and foam claim. The only difference is the BG works-code, whose meaning the record doesn't give; choose on price or availability, not performance (§5).
60720 or the flat 60630?
Dense foam and deep rubber → the hollow-ground 60720; general straight cutting and edge toughness → the flat 60630. Same size and gauge; the grind is the choice.
How thick a foam can it cut?
Thick bun, within its six-inch depth; beyond that, the eight-inch knives. For thinner stock the 4" hollow knives are handier.
How do I sharpen it?
Match the factory bevel with light honing; don't flatten the hollow on a bench stone. Strop often, grind rarely.
Will it rust?
High-carbon cutlery steel: hone it, wipe it dry after wet work. A maintained knife.
