Abstract: A drill tool including a drill body having an inner insert and an outer insert at an end portion of the drill body. The distance from a central axis of the drill body to the outer insert is greater than the distance from the central axis to the inner insert. The cutting edges of the inner and outer inserts can be chamfered with the inner insert chambered at a radially inward portion and the outer insert chamfered at a radially outward portion. The inner insert and the outer insert can be mirror symmetric to one another. The inner insert and the outer insert are mounted to the drill body such that an effective cutting length of the inner insert equals an effective cutting length of the outer insert, the effective cutting lengths being measured in a direction perpendicular to the central axis.

Abstract: A drill tool including a drill body having an inner insert and an outer insert at an end portion of the drill body. The distance from a central axis of the drill body to the outer insert is greater than the distance from the central axis to the inner insert. The cutting edges of the inner and outer inserts can be chamfered with the inner insert chambered at a radially inward portion and the outer insert chamfered at a radially outward portion. The inner insert and the outer insert can be mirror symmetric to one another. The inner insert and the outer insert are mounted to the drill body such that an effective cutting length of the inner insert equals an effective cutting length of the outer insert, the effective cutting lengths being measured in a direction perpendicular to the central axis.

Abstract: A turning tool for internal machining has a spiral groove at a head section entering an inside of a workpiece. The turning tool includes a tool body, which has a head section and a shank section extending from the head section, and a cutting insert. The head section includes the following: a flat portion extending from a front end of the head section, which enters the inside of a workpiece, toward the shank section; an insert pocket formed at an edge of the flat portion as offset from a central axis of the tool body; and a chip flute extending from a proximity of the insert pocket toward the shank section across the central axis of the tool body and including a spiral curved surface on a peripheral surface of the head section. The cutting insert is replaceably mounted to the insert pocket.

Abstract: A drill has inner and outer inserts. The drill includes a drill body having a rotational axis; an inner insert mounted adjacent to the axis at a proximal end of the drill body having an axis-symmetrical contour having four cutting edges and four rounded corners; and an outer insert identical to the inner insert being mounted farther away from the axis than the inner insert. Loci of the inner and the outer insert partially overlap. At the overlapping region, the cutting edge of the inner insert and the cutting edge of the outer insert extend toward the axis in a direction to a workpiece and the locus of the cutting edge of the inner insert protrudes in a direction to the workpiece along the axis of the drill body compared to the locus of the cutting edge of the outer insert.

Abstract: A device and a method for manufacturing an end mill in which the amount of grinding of a blank end mill is small. The device for manufacturing an end mill includes: upper and lower punches; a die; a feed box for supplying a powder of material for the end mill; and a cleaner for eliminating the powder from a top surface of the die. The upper and lower punches are movable up and down relative to each other and have a lengthwise molding cavity formed thereon. The die has a penetrating slit sized to be approximated to the width of the upper and lower punches. The penetrating slit allows the up-and-down movements of the upper and lower punches. The feed box supplies the powder into a space formed by the wall of the penetrating slit and the lower punch.

Abstract: A device and a method for manufacturing an end mill in which the amount of grinding of a blank end mill is small. The device for manufacturing an end mill includes: upper and lower punches; a die; a feed box for supplying a powder of material for the end mill; and a cleaner for eliminating the powder from a top surface of the die. The upper and lower punches are movable up and down relative to each other and have a lengthwise molding cavity formed thereon. The die has a penetrating slit sized to be approximated to the width of the upper and lower punches. The penetrating slit allows the up-and-down movements of the upper and lower punches. The feed box supplies the powder into a space formed by the wall of the penetrating slit and the lower punch.

Abstract: A drill has inner and outer inserts. The drill includes a drill body having a rotational axis; an inner insert mounted adjacent to the axis at a proximal end of the drill body having an axis-symmetrical contour having four cutting edges and four rounded corners; and an outer insert identical to the inner insert being mounted farther away from the axis than the inner insert. Loci of the inner and the outer insert partially overlap. At the overlapping region, the cutting edge of the inner insert and the cutting edge of the outer insert extend toward the axis in a direction to a workpiece and the locus of the cutting edge of the inner insert protrudes in a direction to the workpiece along the axis of the drill body compared to the locus of the cutting edge of the outer insert.

Abstract: An indexable insert for drilling includes front and rear edges opposite to each other and having a rotationally symmetrical relation; and two side surfaces opposite to each other and having a rotationally symmetrical relation. Each side surface has first and second cutting edge portions formed thereon. The first cutting edge portion is disposed farther than the second cutting edge from the center of the blank insert, thereby providing a step between the first and second cutting edge. The first cutting edge is adjacent to the front edge.

Abstract: The present invention discloses a rotary cutting tool which can maintain a secure coupling state between the shank and the cutting head and enhance the durability of the shank by preventing a damage of the shank and the cutting head from being generated.

Abstract: The present invention discloses a tool assembly being capable of reducing considerably an axial length of a working member (tool), in particular, a length of a male spigot to be coupled with a coupling member and transmitting a torque to a working member without generating a loss by means of a secure coupling between a male spigot of a working member (tool) having a short length and a coupling member. A tool assembly according to the present invention comprises a tool including a head to be approached to a work-piece, a male spigot extended from a rear end of the head and a flange formed at a border portion between the head and the male spigot and having a ring shaped flat rear surface; and a coupling member consisting of a first section having a cavity formed on a central portion of a front side thereof for receiving the male spigot and a second section formed at a rear side of the first section and connected to a driving means.

Abstract: The present invention discloses a tool assembly being capable of reducing considerably an axial length of a working member (tool), in particular, a length of a male spigot to be coupled with a coupling member and transmitting a torque to a working member without generating a loss by means of a secure coupling between a male spigot of a working member (tool) having a short length and a coupling member. A tool assembly according to the present invention comprises a tool including a head to be approached to a work-piece, a male spigot extended from a rear end of the head and a flange formed at a border portion between the head and the male spigot and having a ring shaped flat rear surface; and a coupling member consisting of a first section having a cavity formed on a central portion of a front side thereof for receiving the male spigot and a second section formed at a rear side of the first section and connected to a driving means.