Sumitomo Electric Hardmetal Corp.

Sumitomo Electric Industries, Limited

Sumitomo Electric Tool Net, Inc.

Masaaki Jindai

Yoshikatsu Mori

Jun Okamoto

Kazuchika Nasu

Kouki Matsubara

Makoto Abe

Daisuke Murakami

Kazuo Noguchi

Keiji Kinoshita

Yoshiji Sato

Futoshi Takeshita

Ryusei Hamada

Yuki Tsutsumi

Nagatoshi Kunimori

Yuma Kawakami

Hirofumi Tamanishi

Kyosuke Kai

Katsutoshi Fukuda

Masashi Yamada

Kazuhiko Kashima

Kazuyoshi Kimura

Yasuhiro Kajiwara

Kazumasa Kurizuka

Kazuchika Naso

A reamer is rotated about a central axis and has, in a direction along a central axis, a tool front end and a tool rear end that is an end opposite to the tool front end. The reamer includes a blade on a tool front end side. The blade has, on a circumferential surface, a chamfered cutting edge located on the tool front end side, a circumferential cutting edge contiguous to an end of the chamfered cutting edge on a tool rear end side, and a margin that is a surface contiguous to the circumferential cutting edge. The circumferential cutting edge includes a front end portion between a first position and a second position, the first position being an end on a chamfered cutting edge side, the second position having a distance of 1 mm from the first position in a direction of extension of the circumferential cutting edge.

Reamer

The holder has a first surface and a second surface. The head includes a cutting edge portion and a shank portion. The holder is provided with a first hole and a second hole communicating with the first hole, the first hole extending in a third direction inclined by a second angle relative to a second direction extending from the second surface toward the first surface when viewed in a direction parallel to the axis line. The shank portion has a flat surface portion, and is provided inside the second hole. The fastening portion is provided inside the first hole, and is in contact with the flat surface portion. In a plane perpendicular to the axis line, a third angle between the second direction and a fourth direction perpendicular to the flat surface portion is larger than the second angle. The third angle is less than 90&#xb0;.

Cutting tool

The negative land includes: a first region in which a space between the upper cutting edge and the lower cutting edge becomes wider toward the outer circumferential surface; and a second region which is continuous to the first region and in which the space becomes wider toward the rotation axis. In a cross section perpendicular to the rotation axis, the rake face includes a return face continuous to the outer circumferential surface, the return face being recessed opposite to a rotation direction of the drill. When a first boundary represents a boundary between the outer circumferential surface and the first region and a second boundary represents a boundary between the first region and the second region, a length of the first boundary is larger than a length of the second boundary in a direction parallel to the rotation axis. The second boundary is continuous to the return face.

Drill

Provided is a drill having a flat-shaped drill tip and excellent in cutting edge strength and chip removability. The drill includes: a cutting edge extending in a direction at an angle &#x3b1; of not less than 85&#xb0; and not more than 90&#xb0; with respect to a drill axis (line O-O); a flank face contiguous to the cutting edge and having a clearance angle &#x3b2; of not less than 5&#xb0; and not more than 10&#xb0; with respect to the drill axis (line O-O); and a rake face located opposite to the flank face across the cutting edge, the cutting edge includes a recess receding in a direction parallel to the drill axis (line O-O), and the rake face includes a front clearance formed at a side of an outer periphery of the drill.

In a drill, a negative land is provided on a rake face, and a ridge line at an intersecting position of the negative land and a flank face, a ridge line at an intersecting position of the flank face and a margin, and a ridge line at an intersecting position of the negative land and the margin are convex faces in a longitudinal rectangular cross section. When a curvature radius of the convex face of a first ridge line at the intersecting position of the flank face and the negative land is 1, at curvature radius of the convex face of a second ridge line at the intersecting position of the flank face and the margin is 0.8 to 1.5 times the curvature radius of the first ridge line, and a curvature radius of the convex face of a fourth ridge line at the intersecting position of the negative land and the margin is 1.5 to 3.0 times the curvature radius of the first ridge line.

A small-diameter drill having a diameter of &#x3c6;3 mm or less and an end that has undergone cross thinning is provided such that in a front view, a flute portion cutting edge is curved in concave with a degree of concavity with respect to an imaginary straight line in a range of 0.5 to 2% of a drill diameter, the imaginary straight line connecting the radially outer end of the flute portion cutting edge and the radially outer end of thinning portion cutting edge, the ratio of length of the thinning portion cutting edge to length of the flute portion cutting edge is set to 0.6 to 0.9:1, and in an axially perpendicular cross-sectional view, curvature radius of a heel-side flute surface of the flute is set to be smaller than curvature radius of a flute surface along the flute portion cutting edge.

Small-diameter drill

An indexable insert for a drill includes a chip breaker for disposing chips, provided at an upper face thereof along a cutting edge. The chip breaker has at least one recess. The recess is retracted from an end of the chip breaker near the cutting edge toward the center of the insert by 0.2 mm or greater, or an end of the recess near a center hole of the insert communicates with the center hole.

Indexable insert and drill using the same

A throwaway drill capable of machining a workpiece stably in a balanced manner even under high-efficiency, high-load conditions and capable of disposing of chips efficiently and smoothly. The drill carries an outer insert and an inner insert. As shown, each insert has a plurality of cutting edges each having a curved crest, a first slope, and a second slope which is at least partially a curved line. The inner and outer inserts are arranged so that the cutting area to be cut by the outer insert alone is partially cut by a cutting edge portion of the inner insert near its corner, and the cutting area which to be cut by the inner insert alone is partially cut by the crest of one cutting edge of the outer insert.

Throwaway inserts and throwaway drill

A drill capable of drilling a deep hole while keeping high chip discharging ability and having a helical flute whose width and helix angle will not change even after the cutting edges have been regenerated by regrinding. The drill has a tip portion formed with a helical flute having a constant width and helix angle, a rear portion formed with a helical flute which are greater in width and smaller in helix angle than the helical flute formed in the tip portion, and a middle portion provided between the tip portion and rear portion and formed with a helical flute smoothly connecting with the helical flutes of the tip portion and rear portion and having a gradually increasing width and a gradually decreasing helix angle from the tip portion toward the rear portion.

A drill bit structure has a drill bit body 4 and a plate-like hard tip member 9. The cutting end of the drill bit body 4 has a groove 7 extending substantially at right angles to the central drill bit axis, and the hard tip 9 is fitted and fixed in the groove 7. The web thickness is 25-35% of the drill bit diameter and the flute width ratio is 0.4:1 to 0.8:1. The rake angle of each cutting lip 10 measured at positions spaced at least 2/3 of the drill bit diameter radially outward from the drill bit center is in the range of -5.degree. to positive values.

Growing community of inventors

Itami, Japan

Masaaki Jindai