Abstract: A spade blade drill having blended open notch forms on either side of an apex. The notches transition into elliptical flutes which extend outwardly toward sides of the insert. The elliptical flute profiles inhibit chip curling and packing. The sides incorporate a pair of surfaces having a reduced clearance angle for preventing chip packing. The blended open notches are deep and extend across the entire width of the flutes, enhancing heat transfer surface area and allowing chips to flow along the entire flute surfaces. A plurality of chip splitters extend from the flutes across two relief surfaces. The chip splitters have a rounded profile, inhibiting chips from becoming hung in the splitters.

Abstract: The invention relates to an indexable drill for drilling a hole in a metal workpiece. The drill includes an elongated generally cylindrical body having a central longitudinal axis and a pair of cutting inserts. The body includes a tip end portion having first and second recessed pockets on generally diametrically opposite sides of the longitudinal axis. Each cutting insert is removably secured within a pocket and includes at least one cutting edge having an outer peripheral corner and an inner corner. The at least one cutting edge extends linearly from the outer peripheral corner to a curve extending convexly toward an inner region proximate the central longitudinal axis and then to a linear relief edge extending linearly from the inner region in a direction away from the longitudinal axis to the inner corner.

Abstract: A metal cutting drill with replaceable cutting inserts and a length to diameter ratio of four to one or more. Two cutting inserts are positioned in exactly opposed diametric positions, and engage the workpiece in a substantially identical manner to precisely balance the radial forces resulting from drill axially advancing though a workpiece. Through the use of dual cutting inserts, the drill cuts the full circumference of a bore with each one-half revolution and therefore achieves the a faster axial feed rate. By virtue of the inserts being triangular, the curved corners on the cutting edges of the two inserts may be positioned relatively close together and yet sufficient space is left between the inserts to enable the drill shank between the inserts to be relatively thick and strong even at increased length to diameter ratios.

Abstract: A metal cutting drill with two replaceable cutting inserts which are positioned to cut the full circumference of a hole during each one-half revolution of the drill. Each insert is triangular and includes an active cutting edge having a curved corner to enable the insert to cut near the center of the hole. Each insert may be inverted and indexed in order to bring an alternately usable cutting edge into active cutting position. By virtue of the inserts being triangular, the curved corners on the cutting edges of the two inserts may be positioned relatively close together and yet sufficient space is left between the inserts to enable the drill body to be relatively thick and strong.

Abstract: To form holes of small diameter, a drill includes a single cutting insert having an active edge portion with two oppositely facing cutting edges. When the drill is rotated, one cutting edge of the insert cuts the center portion of the hole while the oppositely facing cutting edge cuts the peripheral portion of the hole.

Abstract: A drill having inner and outer indexable cutting inserts for forming a hole in a workpiece. The inner insert is positioned at a non-negative radial angle and is set out axially ahead of the outer insert to increase the service life of the inserts. Tungsten carbide wear strips are spaced angularly around the drill body to limit radial movement of the body and to prevent the body from wearing.