Compound angle cutting edge

A die rule having two converging surfaces forming a cutting portion, wherein the improvement comprises a plurality of side-by-side generally boomerang-shaped indentations formed in one of said converging surfaces defining (a) a plurality of generally equally shaped piercing points, and (b) a substantially linear cutting edge extending from each piercing point toward a next adjacent piercing point, each of the cutting edges extending substantiallly the entire distance between said two piercing points, and in side elevation of the die rule said cutting edge forming an angle with a line through two piercing points of between about one and five degrees, said cutting edges thereby forming a generally check-shaped valley between each of said piercing points, the maximum depth of said valleys being about three-sixteenths of an inch.

In a cutting press including a resilient die pad aligned with an axially reciprocal die rule, the improvement of said die rule having a cutting surface defined by (a) a plurality of generally equally spaced piercing points and (b) a plurality of cutting edges between said piercing points, each of said cutting edges extending from a piercing point toward a next adjacent piercing point for substantially the entire distance between the two said piercing points, said cutting edges extending in, a direction away from the die pad at an angle with a line through the tips of the piercing points of between about only one and fifteen degrees, thereby forming a generally check-marked shaped cutting surface valley between each of said piercing points, said valley having a depth of not more than three sixteenths of an inch, and said die rule piercing points thereby having to penetrate into said resilient die pad for a distance equal only to the depth of the cutting surface valley for the die rule to completely cut through the thickness of the material being cut.

An improved die rule having a plurality of generally equally spaced piercing points and primary cutting edges on a chamfered cutting portion, each of said cutting edges being substantially linear and extending from one piercing point substantially the entire distance to next adjacent piercing point, each cutting edge and a line through the tips of the piercing points defining an acute angle between about one and five degrees, said piercing points and cutting edges being defined by notches formed in the die rule chamfer, said notches being defined by major and minor triangular-shaped notch faces between each piercing point, said major triangular face being bounded on one edge by a primary cutting edge, said notch faces having a common side, and the minor triangular face defining a secondary edge interconnecting the primary cutting edge with a next adjacent piercing point, said primary cutting edge and secondary edge defining a generally check-marked shaped edge configuration between each pair of adjacent piercing points.