Abstract: A tool holder, which has a tool bit pivotal in a recess in one end thereof, extends coaxially through a generally bell shaped piston housing, and through the center of a piston slidably mounted on the holder for limited reciprocation in the housing axially thereof. The piston is urged by a compressing spring to a retracted position against one end of the housing, and has a reduced diameter annular wall that projects coaxially toward the end of the holder containing the tool bit. A tool actuating rod, which is pivotal in an axial bore in the holder, has on one end a lever which extends slidably into an axially extending helical slot formed in the annular piston wall, and is connected at its opposite end to the tool bit. When the piston is in its retracted position, the helical slot in its annular wall causes the actuating rod to swing the tool bit to an inoperative position within the holder recess.

Abstract: A spotfacing and counterboring tool has therethrough an axial bore communicating at one end with a recess containing a pivotal cutter blade connected to an actuator which is reciprocable on the tool between a first limited position in which it moves the cutter blade to an inoperative position within the recess, and to a second limited position in which it moves the cutter blade to an operative position in which the blade projects out of the recess. An expansion chamber in the tool communicates at one end with the axial bore in the tool, and at its opposite end is closed by the reciprocable actuator, which normally is urged resiliently into its first position, when the tool is not being used, and in which position it places the chamber in its contracted mode.

Abstract: A cylindrical tool body is chucked at one end in a drive spindle, and has in its opposite end a cutter blade pivotal into and out of a recess in the tool body between inoperative and operative positions, respectively. The pivoted end the cutter has thereon spaced teeth drivingly engaged with the teeth of a rack formed on one end of an elongate operating rod which reciprocates in an axial bore in the tool body. The opposite end of the rod is secured to one end of a radial pin, the opposite end of which projects slidably into a helical groove formed in the inner peripheral surface of an actuating ring which surrounds the tool body adjacent its chucked end. A friction ring which is rotatable on the tool body adjacent the actuating ring is frictionally engaged with the actuating ring by a friction clutch device which also surrounds the tool body adjacent the friction ring.

Abstract: A cylindrical tool holder has at one end a shank section disposed to be chucked in the drive spindle of a drill press or the like, and has in its opposite end a recess in which a tool bit pivots between an operative position in which it projects radially outwardly from the recess, and in inoperative position within the recess. The bit is connected to one end of an operating rod which is pivotal in a slot in the holder, so that when the rod is swung to one limit position the tool bit is swung to its operative position, and vice versa. An actuating disc which is mounted on the holder for limited rotation relative thereto, is frictionally coupled adjacent its outer periphery with a flywheel which is rotatably mounted on the tool holder, whereby rotation may be transmitted by the holder through the flywheel and friction coupling to the actuating disc. The actuating disc has thereon two spaced pins.

Abstract: Adjacent one end thereof the shank of a back spotfacing tool has therein a transverse slot, and a cutter mounting pin which extends between opposite sides of the slot parallel to the shank axis. A cutter has in one end thereof a U-shaped slot which is inserted removably over the pin to support the cutter for limited pivotal movement about the pin into and out of an operative position in which a flat, external, limit surface formed on the side of the cutter remote from the open end of its U-shaped slot engages the bottom of the slot in the shank to support the cutter for a cutting operation, and to prevent removal of the cutter from the pin. The cutter may be swung manually to an inoperative position in which the open end of its slot is positioned to permit removal of the cutter from the pin, or the replacement thereof over the pin.

Abstract: A boring head with a longitudinal axis includes a leading cutting portion and a trailing portion. A pair of adjustable work engagement devices are releasably secured to the leading portion by individual fasteners. Individual mechanisms for adjusting the position of each of the work engagement devices in a first direction generally parallel to the longitudinal axis of the boring head, and individual mechanisms for adjusting the position of each of the work engagement devices in a second direction, generally transverse to the first direction, are provided. The first and second direction adjusting mechanisms are positioned coaxially of each other in the boring head. Each work engagement device is adjustable in the first and second directions individually and independently of the other.

Abstract: A tool holder has on its lower end an inverted, frusto-conically shaped bearing surface which is releasably seated coaxially in a correspondingly shaped opening which is formed in the upper surface of a stationary support. Intermediate its ends the bore wall which defines the frusto-conically shaped opening in the support has therein a shallow, circumferential recess, which is connected through a port in the support with a supply of fluid under pressure. In use the lower end of the tool holder is held in the opening in the support solely by gravity; and a tool, which is mounted in the upper end of the holder, is positioned adjacent a conventional gauging device which can measure tooth height and tool runout. Fluid under pressure is supplied to the recess in an amount sufficient to cause the tool holder to be elevated slightly without breaking the seal between the recess and the frusto-conically shaped bearing surface on the tool holder, whereby the tool holder can then be readily rotated manually.