The primary grind is where a knife first begins to narrow into a cutting edge from the thickness of the main stock of the blade. The cross-sectional shape of the blade of a knife or sword is made up of different planes, or grinds. The sharp, cutting edge of the blade is often further ground at a secondary, or 'edge', bevel. This allows the blade to have more functions than otherwise possible with a strictly wedge or chisel shape.
The Swiss Army Knife is an example of a knife with a primary bevel and an edge bevel. By contrast, a blade composed of a single flat grind from stock thickness to the cutting edge is known as a 'full flat ground' blade. The cutting properties of a blade are determined by the type of metal, the hardness of the blade, and the grinding pattern (e.g. convex, concave, teardrop).
Famous quotes containing the words primary and/or grind:
“A fact is a proposition of which the verification by an appeal to the primary sources of our knowledge or to experience is direct and simple. A theory, on the other hand, if true, has all the characteristics of a fact except that its verification is possible only by indirect, remote, and difficult means.”
—Chauncey Wright (1830–1875)
“Politics is, as it were, the gizzard of society, full of grit and gravel, and the two political parties are its two opposite halves,—sometimes split into quarters, it may be, which grind on each other.”
—Henry David Thoreau (1817–1862)