Abstract: A tool including a working portion with a working member, a side surface and an end surface. The working portion includes a passage passing through the side surface and the end surface. At least one seal is adapted to restrict fluid flow through the side surface and the end surface and at least partially defines a pressure chamber. The working member is adapted-to be selectively pivotally positioned by selectively pressurizing the pressure chamber. The tool similarly enables unique methods of working workpieces.

Abstract: A tool including a working portion with a working member, a side surface and an end surface. The working portion includes a passage passing through the side surface and the end surface. At least one seal is adapted to restrict fluid flow through the side surface and the end surface and at least partially defines a pressure chamber. The working member is adapted to be selectively pivotally positioned by selectively pressurizing the pressure chamber. The tool similarly enables unique methods of working workpieces.

Abstract: The invention provides an apparatus for positioning a cutter a tool relative to a spindle of a machine tool. The machine tool include a spindle having a rotating axis and a spindle housing for supporting the spindle for rotation about the rotating axis. The apparatus includes a shank which is adapted to be mounted to the spindle of the machine tool. A piston is provided in the shank for movement along an axis which defines an angle relative to the rotating axis of the spindle. A cutter, for machining a workpiece, is connected to the piston. A first fitting member is provided on the shank and a second fitting member is provided on the piston so as to be able to fit to the first fitting member. Each of the first and second fitting members include an abutment provided on the first and second fitting members to contact each other in the direction of the axis.

Abstract: The invention concerns a device for infinitely variable support of a tool on a drivable tool spindle of a machine tool. To provide such a device which allows exact adjustment of the tool within a range of one millimetre, at the same time avoiding centrifugal force-related imbalances, it is proposed that the tool is exchangeably attached to a tool carrier which is mounted in a housing so as to be pivotable about an axis of rotation of the tool carrier extending at an angle, preferably at a right angle, to the axis of rotation of the tool spindle.

Abstract: A tool for cutting machining a workpiece, including a cutter plate supported on a holder for machining a surface and additionally comprising a tool projecting from the body of the tool. The cutter plate is supported on a holder which is in turn supported on a rotatable eccentric such that rotation of the eccentric moves the holder radially. A cooperating converting device converts axial movement of an actuating device into rotation of the eccentric through intermeshing gear elements. A second tool, e.g., a reamer, is moved by a second push/pull rod axially with respect to the body of the tool and into the workpiece, and the second tool is supported on the axis of the main body.

Abstract: The invention involves a tool head 10, which can be rotated around an axis of rotation 24, with a tool-holding fixture 14, 16 for a tool 20 having a cutting edge 18 and with equipment 38, 40, 44 for adjustment of the radial position of the tool cutting edge 18 with regard to the axis of rotation 24. The invention distinguishes itself by the fact that the tool-holding fixture is divided up into a base element 14, which is supported in a first bearing system 40 in a carrier sleeve 44 so as to be able to rotate around the axis of rotation 24, and a tool-holding element 16, which is supported in a second bearing system 38 in the carrier sleeve 44 so as to be able to rotate around an eccentric axis 42 that is positioned in an eccentric fashion, as well as in parallel to, the axis of rotation 24.

Abstract: An apparatus radially adjusts a position of a plurality of tool cartridges of a machine tool having rotatable, concentric, elongate, inner and outer drive spindles. A plurality of pockets are formed through the outer spindle to communication with a passage for the inner spindle. A wedge is disposed in each pocket for longitudinal movement in response to relative rotation of the inner spindle when the inner spindle is in a predetermined selectable position. A rotatable member is disposed in each pocket and has a threaded external surface operably engageable to move the rotatable member longitudinally in response to rotation of the rotatable member with respect to the outer spindle. A tool cartridge is operably engaged within each pocket for radial movement in response to relative movement of the corresponding wedge.

Abstract: A tool including a working portion with a working member, a side surface and an end surface. The working portion includes a passage passing through the side surface and the end surface. At least one seal is adapted to restrict fluid flow through the side surface and the end surface and at least partially defines a pressure chamber. The working member is adapted to be selectively pivotally positioned by selectively pressurizing the pressure chamber. The tool similarly enables unique methods of working workpieces.

Abstract: Cutting tool, such as a gun reamer or a drill, with a rotating cutting blade and a rotating support member for supporting the workpiece, where at least one of the cutting blade and the support member are selectively biased. The selective bias on the blade and/or the support member is preferably effected by selectively pressurized fluid which bears on the blade member and/or the support member.

Abstract: A tool for the machining of workpiece surfaces, especially of drilled-hole surfaces, has at least two parts which are displaceable relative to each other. The tool for the machining of the workpiece surfaces is rotatable and includes at least one control member (19) which is displaceable relative to the tool (1) substantially perpendicularly to the axis of rotation (9) of the tool. The control member, preferably from a preset threshold speed of rotation, effects a movement of one part (5) relative to the other (3).

Abstract: A tool with a fluid axis wherein the fluid axis is controlled based on reference information from other tool axes, such as positional information relating to other tool axes. The reference information may be directly measured or may be determined from a control program used to control the tool with respect to the other axis or axes. Feedback information from the fluid axis itself, such as fluid pressure of the fluid axis, may also employed as to help determine the reference signal for controlling the fluid axis.

Abstract: The cutting tool for machining valve seats comprises a driving system, a machining head, a pilot, a depth gauge, and a system controller. The driving system provides rotational movement and vertical movement for the machining head which is controlled by the system controller. The machining head further comprises a pinion feed driving assembly and a universal cutting blade. The pinion feed driving assembly causes the cutting radius of the cutting tool to decrease as the machining head rotates. The pilot is attached to the bottom of the machining head to provide a means for centering the cutting tool. The depth gauge is disposed on the driving system and is electrically connected to the system controller. The depth gauge measures the distance between a valve seat and the cutting blade. The system controller includes memory and programming for controlling the operation of the cutting tool. An operator can input the parameters that define the geometry of the valve seat profile.

Abstract: A cutting tool insert is mounted on a flexure member that is mounted on the end of a boring bar. The construction of the flexure member is such that it is compliant along a radial axis perpendicular to the direction of tool advancement, but relatively stiff along a feed axis in the direction of tool feed, and along a cutting axis in the direction of tool rotation. Any displacement of the flexure member and cutting tool insert as a result of workpiece engagement or boring bar deflection is sensed by laser detectors. Signals from the laser detectors are coupled to a computer that rotates with the boring bar and are used to provide feedback signals to an actuator in contact with the flexure member. The actuator displaces the flexure member to correct the position of the tool insert.

Abstract: For correcting eccentricity of a tool chucked in a first part of an at least two-part toolholder, which first part is detachably connected via clamping means to a second part of the toolholder, which is clamped in a machine tool and rotates about an axis of rotation, setting means are provided by means of which the first part of the toolholder is displaceable relative to the second part. Radial eccentricity of the tool can thereby be corrected. Furthermore, between the first and second parts of the toolholder, two rings are disposed coaxially with, and rotatingly about, the axis of rotation. These rings have annular surfaces, one of which is inclined relative to the other at a certain angle. By mutual rotation of the two rings, the first part of the toolholder can be inclined relative to the second part, whereby an angular error of the tool can also be corrected.

Abstract: A rough boring tool is composed of a boring rod having a tool hole which is provided with a base line and a plurality of reading scales. The rough boring tool is further composed of a boring tool engaged with the tool hole and provided with a plurality of measuring scales corresponding in location to the reading scales and forming an angle with the base line. The advancement quantity of the boring tool can be easily observed with the naked eye by converging the reading scales of the tool hole of the boring rod and the measuring scales of the boring tool.

Abstract: A tool head for the precision cutting of a surface of a rotating workpiece has a cutting tool which is movable in opposition to the force of a restoring spring from an initial position into an operating position with respect to the workpiece via an actuating drive. The actuating drive is formed by a translatorily movable driving element and a transfer element which converts the driving movement into an adjusting movement. The driving element used for adjusting the cutting tool from the initial position to a machining position is formed by an expansion bar actuated by magnetostrictive principles.

Abstract: For influencing the run of a deep hole drilled passage in a metallic or non-metallic material a pusher pad (6) variable in strength and position is interposed between the drill rod (2) driving the drill tool (1) or the drill tool (1) itself and the inner wall of the drilled passage so that it causes a bending of the drill rod such that the drill tool assumes a changed run. The variation in the position and/or thickness of the pusher pad (6) can be fed back to the sensing of the corresponding position of the drill tool (1) and controlled by the results of sensing.

Abstract: A boring bar for machining of borehole surfaces which are arranged axially spaced from each other, in particular crank-shaft and/or cam-shaft bearing holes. The bar has at least one, and preferably a plurality, of cutting devices and at least one, and preferably a plurality of, guide devices each associated with a cutting device. A fluid pressure actuating device acts on both the cutting devices and the guide devices. The actuating device effects a setting movement of each of those devices against a respective defined stop by application of fluid pressure through the boring bar to the cutting devices and the guide devices.

Abstract: A cutting tool has a slidable cutting-blade chip 5A, in which a slider 7 is slidably mounted into a groove 6 formed in the cutting tool main body 1, to offset a pressing force applied to the bottom face 6c of the groove 6 through the slider 7, to prevent abrasion of the slider 7 and the groove 6 and uneven abrasion of serration grooves 7a and 8a of the slider 7 and a spacer 8, and to suppress backlash of the slider 7. A spacer 9 is detachably disposed between one side face 6a of a groove 6 and a slider 7, a plate 22 is disposed between another side face of the slider 7 and another side face 6b of the groove 6 so as to press the plate 22 toward the side face 6a. A protruding section 21 and a dent section 24 each have a V-shape cross-section and are formed on another side face of the slider 7 and on one side face of the plate 22, respectively, wherein the protruding section 21 and the dent section can come into contact with each other.

Abstract: An apparatus and method for compensating a radial load between relatively axially articulatable inner and outer members, which in the exemplary embodiment are a spindle cartridge and spindle housing of a slip spindle drill assembly. The apparatus includes a strut having a curved inner end seated in a first seat on an outer surface of the inner member, and a curved outer end seated in a second seat supportably retained by a cap disposed adjustably in an opening through the outer member. The strut applies a radial force between the inner and outer members to compensate for the radial load. The strut is also pivotally disposed between the inner and outer members, whereby the strut pivots during relative axial articulation therebetween. The strut is substantially disposed radially relative to a direction of axial articulation when the inner and outer members are relatively axially articulated approximately one-half the axial articulation range.

Abstract: The invention relates to a backspot facing tool for machining operations. At least one cutting fluid jet is used to actuate a cutter included in the tool, causing it to move from a retracted to a non-retracted position.

Abstract: A tool head, in particular a fine adjustment head for use in machine-tools, may be coupled to a rotary machine spindle (26) and has a slide (16) that may be adjusted transversely to the axis (12) of the base body and is provided with a projecting tool-receiving part (14) on its front face. A measurement arrangement (18) is provided for directly measuring the adjustment path of the slide (16) in relation to the base body (10). The tool head further has an adjustment motor (20) that acts on the slide (16) in the direction of adjustment and an external current supply arrangement (22) for electronic components integrated into the tool head and for the adjustment motor (20). In order to obtain a compact design with high adjustment precision, the adjustment motor (20) is arranged with its cylindrical housing (45) in a recess (46) of the base body (10) that extends transversely to the direction of adjustment of the slide (45) and to the axis of the base body.

Abstract: A portable facing head comprises a feed body portion in threaded engagement with lead screws that extend through the feed body. The lead screws are translated through the feed body by a worm gear enclosed within the feed body wherein the worm gear is rotated by action of a star feed. The star feed is rotated by contact with a cam member extending outwardly from a torque bar positioned adjacent the feed body such that upon rotation of the feed body about a rotational axis, the star feed is incrementally rotated by the cam member thereby effecting incremental rotation of the worm gear and incremental linear translation of the lead screws through the feed body. Directional movement of the lead screws through the feed body is selectively set at forward, reverse or zero during rotation of the feed body by manipulation of a torque arm handle to position the cam member.

Abstract: A drill bit including a body, a drill bit fixed onto the body, a thrust transmitting member arranged on the body and having a contact portion, and an undercut cutting member housed in a guide groove provided in the side face of the drill bit. The undercut cutting member is freely movable and provided with an undercut edge at the lower end thereof. A pull-up spring is installed to operably move the undercut cutting member, and a working force transmitting mechanism is installed on the body coupled with the thrust transmitting member and with the undercut cutting member, to press down the undercut cutting member against the resistance of the pull-up spring by the approaching movement of the body and the thrust transmitting member thereby to cause the undercut cutting edge to protrude outwardly of the drill bit body surface.

Abstract: A pressure controlled cutter bit or drill bit retainer in the form of a revolving drill head with hydraulic precision adjustment of the drill bit arranged at a central extension, which is displaceable from its original position by small amounts around a pivot axis by a pressure motor, wherein this displacement occurs without any parts mechanically rubbing against each other and the dimensioning of the pressure motor and extension defining the transmission ratio conditions are selected in such a way that the travel of the drill bit guided along a curved path is greater than the travel of the pressure motor output produced by volume change, and wherein the overall volume of the pressure motor is selected to be slightly greater than the volume required for moving the pressure motor output.

Abstract: In a cutting tool optimally used for working a valve hole in a cylinder head of an engine, a U-shaped groove (11) having a U-shaped cross section is formed to extend along a generatrix of a substantially conic tool main body (1), and a slider (160 carrying a cutting tip (5A) is slidably fitted in the U-shaped groove (11). A spacer (12) formed with a serration groove (12a) is detachably mounted between a wall surface (11a) of the U-shaped groove (11) and the slider (16). The slider (16) is formed on its side surface with a serration groove (16a) which engages the serration groove (12a). The slider (16) is biased toward the wall surface (11a) with an elastic force by a biasing means (15) which is provided at another wall surface (11b) of the U-shaped groove (11) and includes a pressing pin (17), a disk spring (18) and a set screw (19).

Abstract: A boring tool comprises a rotating tool body, a tool slide transversely displaceable therein, a cutting plate arranged on the tool slide and a micrometer screw for adjusting the tool slide, this micrometer screw being mounted transversely to the axis of rotation of the boring tool so as to be rotatable and axially non-displaceable. The micrometer screw is mounted in the tool body at a distance from the tool slide and drives a drive slide displaceable transversely to the axis of rotation of the tool body. A transfer lever is pivotally mounted in the space between drive and tool slides and engages with one arm on the drive slide and with the other arm on the tool slide such that when the drive slide is displaced the tool slide is entrained in the opposite direction to the drive slide.

Abstract: The drilling device has a radially resilient shaft (3) which allows radial displacement of the drill bit (4) and the drill head (5). The radial displacement can be caused by a vibration device (8), but a self-excited oscillation of the resilient shaft (3) can also provide the desired radial displacement of the drill bit and the drill head. The drill shank (2) has a sleeve-shaped shank extension (17) provided with a damping chamber (18) filled with a damping agent (19) and the resilient shaft (3) is in the damping chamber (18) which is sealed by a radially resilient seal (21) surrounding the resilient shaft (3).

Abstract: Mass compensating device and a rotary head used for machining high precision bores incorporating the mass compensating device, including ring shaped counterweights having balancing masses, an angular displacement system including toothed gears which mesh with internal gears on the counterweights and a rotating external ring arranged in the boring head.

Abstract: A displaceable cutting tool shank holder, in particular for a rotary boring head threadable on a main spindle of a machine tool, having one end with a substantially H-shaped cross section provided with parallel linear tracks cooperating with linear tracks on internal projections in a member connected to the rotary boring head to thereby define guideways in which bearing balls on roller are situated. The projections are arranged on an end portion or top portion of the rotary boring head. An opposite end of the tool shank holder has a recess wherein a cutting tool shank is lodged.

Abstract: A substantially conical tool body 1 has a groove 11 extending in the direction of generating line. The groove 11 slidably receives a slider 16 carrying a cutting insert 5A. A spacer 12 having serration grooves 12a is interposed between one wall surface 11a of the groove and the slider 16. Serration grooves 16a are formed in one side surface of the slider 16. A wedge member 13 is detachably interposed between the wall surface 11b of the groove 11 and the slider 16 so as to press the slider 16 to bring the serration grooves 12a16a into engagement with each other. Any wear and deformation due to cutting load appear on the spacer 12 and the wedge member 13, so that original mounting and positional precision of the slider 16 can easily be recovered by renewing these members, thus maintaining a required level of machining precision.

Abstract: Alternative tool wear compensation modules employing drawbar actuated tool position adjustment or electrically activated solid-state prime mover adjustment including means for physically sensing and verifying the extent of adjustment without awaiting the gaging of successive work piece dimensions following compensation adjustment. In one embodiment, a piezoelectric stack is employed with a flexure unit mounted tool to produce adjustment deflection through controlled voltage applied to the piezoelectric stack.

Abstract: An adjustable cartridge to be mounted in the end of a boring bar, the cartridge including an anvil rotatably affixed to said boring bar, said anvil including a pocket into which a indexable insert is affixed. The anvil is secured in an axially oriented slot which includes an arcuate seating face which includes a key and key way slot. Rotation of the anvil within the slot effects radial adjustment of the insert a key pin serves to pivotally secure the cartridge within the pocket. In addition, the level or back taper of the insert can be adjusted.

Abstract: Device for producing a drilled hole with an undercut in a facing panel, consisting of a drilling machine and a drilling tool for forming the drilled hole connected to the drilling machine via an adapter for transferring torque; and a holding device of a supporting stand having a swivel bearing for holding the drilling machine so that it can swivel with the drilling tool attached to it. To extend the service life of the drilling tool the adapter consists of a drive part connected to the drilling machine so as to transfer torque and a tool holder connectable with the drive part and a device for releasably securing the tool holder to the drive part so that the center line of the tool holder is inclined relative to the center line of the drive part, which is aligned with the drive axis of the drilling machine, so that only a portion of the circumference of the drilling tool engages the panel during formation of the drilled hole.

Abstract: A deburring tool for deburring bore edges of bores consists of a rotating tool holder on which one or more radially adjustable cutting knives are arranged. To ensure universal application of the deburring tool, additional cutting tools are arranged on the tool holder in axial distance from the known cutting knives so that additional chamfers and plane surfaces in the area of and outside the bore can be machined. Also, a drill or milling cutter can be connected to the tool holder on the front side of the tool holder.

Abstract: A device for producing drilled holes with an undercut, especially in facing panels, has a drilling machine, a drilling tool, an adaptor receiving the drilling tool and connected with the drilling machine so as to transfer torque, a holder, a bearing bush secured in the holder and provided with a rotatable and swivelable guide sleeve, a wobble plate secured on the drilling machine and the guide sleeve, a plurality of cylinders arranged on the holder concentrically about a center line of the guide sleeve and engaging the wobble plate. The cylinders are actuated and controlled in succession to produce a wobbling movement for reaming out an undercut in a drilled hole.

Abstract: A deburring tool has at least one cutting blade mounted in a guide recess of the tool for deburring and chamfering bores. The blade is of rectangular shape with forward, non-cutting end face and longitudinal side faces extending rearwardly from the end face. At least one side face has a non-cutting glide surface extending rearwardly from the end face at a first angle, and a cutting edge extending rearwardly from the glide surface at a second, different angle.

Abstract: Disclosed is an improved tool mount for a machining apparatus comprising essentially a tool holder cubic and an adapter to be detachably attached to the tool holder cubic. The tool holder cubic has a center guide projection, a notched cylindrical rod rotatably fitted in a semicircular hole of the center guide projection, and means for rotating the notched cylindrical rod. The adapter has a center slot to accept the center guide projection of the tool holder cubic, a semicircular recess made so as to allow the notched cylindrical rod to enter when it turns; and means for rotating the notched cylindrical rod to enter the semicircular recess, thereby allowing the adapter and the tool holder cubic to nest together. This arrangement permits easy and quick changing of different tools in a machining apparatus, and automatization of tool exchanging.

Abstract: The present invention relates to a boring head constituted by a body (1) provided with a radial piston (2) for reception of a boring tool (3) gripped by means of a screw (4), said piston (2) being adjustable in position by means of a micrometric screw (5), characterized in that the body (1) is provided also with a slide block (6) effecting the guidance, the orientation and an end-of-movement abutment for the piston (2) for reception of the boring tool (3) and with a balancing device (7) with independent counterweights (8 and 9).

Abstract: A pressure controlled cutter bit or drill bit retainer in the form of a revolving drill head with hydraulic precision adjustment of the drill bit arranged at a central extension, which is displaceable from its original position by small amounts around a pivot axis by a pressure motor, wherein this displacement occurs without any parts mechanically rubbing against each other and the dimensioning of the pressure motor and extension defining the transmission ratio conditions are selected in such a way that the travel of the drill bit guided along a curved path is greater than the travel of the pressure motor output produced by volume change, and wherein the overall volume of the pressure motor is selected to be slightly greater than the volume required for moving the pressure motor output.

Abstract: Mechanical fine adjust boring head including an adjustment drive train through a worm wheel drive of an eccentric cam orbiting a drive key engaging a slide to effect linear radial adjustment. Anti-friction bearings for the cam and orbital drive connection between the cam and drive key provide for smooth nonbinding adjustment.

Abstract: An undercutting drill for obtaining a drill hole with a conical undercut. A drill shaft is provided connected in an articulated manner through a housing and containing a universal joint to a clamping shank. The face of the housing facing the joint. The drill shaft is provided with a plate having a stopping face, the vertical centerline of which is tilted in relation to the longitudinal axis of the drill shaft.

Abstract: A boring attachment has a boring head with a transversely adjustable slide for setting the boring cutter. The slide has a bore for receiving (clamping) a holding device, at a length which is adjustable in the axial direction, so that the holding device is longitudinally displaceable by an amount equaling at least twice the diameter of the recess. Loading at the cutter holder is essentially completely eliminated when the holding device is located in a transversely displaced position which is within the principle operating range of the boring head by providing appropriate bores in the body of the boring head. A relatively small overall height for the boring head contributes to optimal stability of the boring attachment.

Abstract: A boring type tool includes mean for biasing a cutting bit in a first radial direction with respect to an axis of rotation and means for adjustably moving the cutting bit to a predetermined desired position against the force of the biasing means. The adjustable moving means includes a fluid pressure source for an incompressible electrorheological fluid and a means communicating with the fluid pressure source and the cutting bit for the flow of electrorheological fluid for adjustably moving the cutting bit in a direction opposing the first radial direction in proportion to pressure being generated by the fluid pressure source. A valve means is operably associated with the communicating means for effecting changes in the dynamic stiffness of the electrorheological fluid in response to an electric field.

Abstract: A cutting tool includes a motor and control inside the cutting tool for adjusting the cutting radius of the cutting tool. The cutting tool is adaptable for use with machine tools which do not include integral systems for moving parts of the cutting tool adjust the cutting radius.

Abstract: An apparatus for the fine radial adjustment of a turning tool of a rotating cutter head with a first converter for converting a low pneumatic control pressure into a fluid pressure and with a further pressure converter for converting the intermediate pressure into a high working pressure for acting upon an adjusting medium, adjusts a turning tool. The first converter is stationary outside of the rotating head and is connected to the second converter, which is disposed in the rotating head, over a connection of conduits providing a rotary transmission for pressure transformation. The intermediate pressure is set higher than the control pressure, but lower than the adjusting pressure for unloading the rotary transmission.

Abstract: A boring tool and a method of operation are provided for boring two concentric holes of precision diameters and depths in a single operation. The boring tool includes an elongated tool body, a shank for attachment to a standard adjustable boring head which is used on a manual or numerical control milling machine and first and second diametrically opposed cutting edges formed for cutting in opposite directions. The diameter of the elongated tool body is substantially equal to the distance from the first cutting edge tip to the axis of rotation plus the distance from the second cutting edge tip to the axis of rotation. The axis of rotation of the tool is spaced from the tool centerline a distance substantially equal to one-half the distance from the second cutting edge tip to the axis of rotation minus one-half the distance from the first cutting edge tip to the axis of rotation.

Abstract: A counterbore for the bilateral mounting of plane surfaces on through holes that consists of a tool head that may be driven rotationally by means of a shank. The counterbore has two cutting heads with cutting edges pointing in opposite directions. The cutting heads are guided within the tool head in take-up slots in such a way that they may be moved out radially and fixed in a preselected position. The cutting heads lie against one another within the area of the take-up slots. In order that high cutting forces may be transmitted easily in a tool head of small dimensions, the cutting heads are guided through a guide slot extending in a radial direction and positioned in the take-up slots of the tool head.

Abstract: A machine has a movable member capable of releasably supporting a tool for performing an operation on a workpiece, and a supply of pressurized fluid. The tool includes an electric circuit which is provided with power from an electrically generator drivingly connected to a turbine driven by the machine's supply of pressurized fluid. The turbine may be in the form of a Pelton Wheel, the buckets of which are rotated by directing the pressurized fluid at them in a jet. The pressurized fluid may be a liquid or a gas. The tool may take one of several alternative forms, such as a boring bar or measuring probe.

Abstract: A holder for a rotary cutting tools has a holder body fixed to a spindle of a machine tool. A rotatable shaft concentric with the holder body and having a tool-mounting portion at one end thereof is coupled at its other end portion to the holder body to receive torque from the holder body. The rotatable shaft is so mounted as to be radially displaceable and inclinable relative to the holder body. A positioning member is fixedly disposed on the machine tool body radially outwardly of the spindle. A cylindrical casing disposed radially outwardly of and rotatably engaged with the rotatable shaft such that the casing and the shaft are rotatable relative to each other, the casing being engageable with the positioning member for accurate positioning thereof by the positioning member, and thereby positioning the rotatable shaft.