Kennametal Inc.

Yamawa Manufacturing Limited

Yamawa Mfg. Co., Ltd.

Steven R Burns

Willard E Henderer

Stephen Michael George

Sadayuki Akaki

Alan L Barrows

Dennis J Greene

A method of making a cutting tap includes: providing an elongate tap body having an axial forward end, an axial rearward end and a central longitudinal axis; securing the axial rearward end of the tap body in a grinding machine; and forming in the axial forward end of the tap body a correction grind and a main flute in one continuous grinding operation. A cutting tap made by the invention is also provided.

Method of making a cutting tap with a correction grind

A cutting tool that includes an elongate body that has a forward end and a rearward end. The elongate body has a fluted portion that beginning near and extends in a rearward direction from the forward end. The fluted portion has a flute that defines a cutting edge. The flute presents a concave cutting face wherein the concave cutting face is defined by a first radius. The flute further presents a concave core surface adjacent to the concave cutting face wherein the concave core surface is defined by a second radius. The flute presents a convex heel surface adjacent to the concave core surface wherein the convex heel surface is defined by a fourth radius.

Spiral flute tap

A low torque tap includes a shank portion with a driving square and a thread cutting portion. The thread cutting portion includes a threaded body with one or more asymmetrical straight flutes that run essentially parallel to a longitudinal axis of the tap. The thread cutting portion also includes one or more short angular flutes or spiral points and a tapered chamfer. For tapping steel alloys, the cutting edges of the straight flutes and the spiral points have a rake or chordal hook angle of between about 5 and 15 degrees. For tapping ferrous materials, the tap is made from molybdenum-enriched high-speed steel and may be coated with a wear-resistant, friction-reducing layer. A second, outer layer, such as molybdenum disulfide, may be applied over the wear-reducing layer for further reduction in friction. For tapping non-ferrous materials, the tap may be coated with a layer of material containing carbon.

Low torque tap

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East Ryegate, VT, United States of America

Steven R Burns