Abstract: A tool holder has a chuck portion with a retaining bore in which a cutting tool can be inserted. The tool has flat surfaces extending from its end, and a circumferential groove at rear ends of the flat surfaces. When the tool is inserted into the retaining bore, first protrusions of the tool holder pass through spaces between the flat surfaces and the inner wall of the retaining bore and fitted in the groove. When the tool is turned, the protrusions move in and engage the side edges of the groove, thus preventing the tool from pulling out of the chuck portion. When the first protrusions are fitted in the groove, second protrusions of the tool holder are located on the flat surfaces. When the tool is turned, the second protrusions are received in ends of the respective spaces, thereby preventing rotation of the tool relative to the chuck portion.

Abstract: A tool holder has a chuck portion with a retaining bore in which a cutting tool can be inserted. The tool has flat surfaces extending from its end, and circumferential groove at rear ends of the flat surfaces. When the tool is inserted into the retaining bore, first protrusions of the tool holder pass through spaces between the flat surfaces and the inner wall of the retaining bore and fitted in the groove. When the tool is turned, the protrusions move in and engage the side edges of the groove, thus preventing the tool from pulling out of the chuck portion. When the first protrusions are fitted in the groove, second protrusions of the tool holder are located on the flat surfaces. When the tool is turned, the second protrusions are received in ends of the respective spaces, thereby preventing rotation of the tool relative to the chuck portion.

Abstract: A shrinkage-fit tool holder having a tool holder body 11 having a portion 2 adapted to be connected to a machining center, a manipulator-engaging portion 3, a chuck portion 4 and a tool-holding member 6 for firmly holding a shank of a cemented carbide tool by shrinkage fitting, at least the tool-holding member 6 being made of specialty steel having an austenitic structure that is strengthened by precipitation hardening or work hardening.

Abstract: A tool holder having a holder body, a collet, an intermediate rod, a clamp bolt and a pull stud. The collet and the intermediate rod are integrally connected by screwing. A spacer is mounted to the front end of the holder body and has an opening hole with a diameter nearly matching with the diameter of the shank portion of the cutting tool. In the opening hole, a tapered groove portion with an enlarged diameter portion on the rear and a reduced diameter portion on the front is formed, and in this groove portion, a sealing O-ring is mounted. A cap for holding the spacer is screwed down to the front portion of the holder body, and the cap and the holder body come in pressure-contact at each other's tapered surfaces.

Abstract: A tool holder having a holder body, a collet, an intermediate rod, a clamp bolt and a pull stud. The collet and the intermediate rod are integrally connected by screwing. The collet is retracted into the holder body via the intermediate rod by rotating the clamp bolt in the first direction, and presses and holds a cutting tool. In this event, a head of the clamp bolt comes in pressure-contact with a stepped surface of the holder body by surface friction and rotates. On the other hand, in order to release the cutting tool, the clamp bolt is rotated in the second direction opposite to the first direction. In this event, the clamp bolt is rotated by rolling friction via steel balls inserted between the head and a center hole of the holder body, and the collet is pressed out forward.

Abstract: A protective cover comprising a tool covering portion and a pressure contact tube portion. The pressure contact tube portion is formed on its periphery with a multiplicity of resilient pieces. When the pressure contact tube portion is fitted over a front end portion of a tool holder, the resilient pieces come into pressure contact with a cylindrical case and a chucking nut, both of the tool holder, whereby the protective cover is securely attached to the tool holder.

Abstract: A method of determining the minimum number of segments of a metal collet for a cutting tool holder having a truncated conical portion having a small-diameter end and a cylindrical portion connected to the small-diameter end. The collet is formed with slits extending axially inwards from the opening thereof for inserting a cutting tool and arranged at equal angular intervals. The slits extend to the cylindrical portion. The minimum number of segments is determined to be within the range where the geometrical moment of inertia of the section with respect to a line which passes through the centroid of the section and is perpendicular to a radical direction of the collet, as plotted against the number of segments, becomes substantially constant. With this arrangement, each segment has a suitable deflectability so that the collet can grip a cutting tool with sufficient force and accuracy and over a wide chucking range.

Abstract: A unit for mounting a cutting tool on a machine tool. The casing is divided into two portions, one with a joint for connection with the spindle of a machine tool and the other with a chuck unit for mounting a cutting tool. The shank itself is also divided into two portions. Even so, cutting oil is supplied through the unit case and injected toward the cutting tool at any cutting angle.