Abstract: A vertical mill gearbox includes a drive shaft mounted in a casing for rotation about a rotation axis, and an intermediate shaft configured as a hollow shaft and mounted in the casing for rotation about a vertical second rotation axis. The intermediate shaft has a bevel gear meshing with a bevel-gear pinion of the drive shaft. A torsion shaft is received in fixed rotative engagement with the intermediate shaft and sized to extend beyond the intermediate shaft to define a projecting section to which a sun gear rotatably driven via the intermediate shaft is fixed. A planet carrier is mounted in the casing for rotation about the second rotation axis and rotatably supports an internal gear having an internal tooth system. Mounted to the planet carrier is a rotatable planet gear which meshes with the sun gear and with the internal tooth system of the internal gear.

Abstract: An attachment to a milling machine having a rotary drive, particularly useful for cutting sharp interior corners in a workpiece, comprising a rotary shaft couplable to the rotary drive of the milling machine so as to be rotatable about the shaft's longitudinal axis. The attachment further comprises a conical cutter member having a rotary axis, an apex located on the axis, and at least one external conical surface portion having a leading end at the apex and a trailing end spaced apart from the rotary axis and from the apex along the rotary axis. The conical cutter member has a cutting edge constituting a part of the conical surface portion and extending between the leading and trailing ends thereof. The rotary axis of the conical cutter member is oriented transversely though not perpendicularly to the shaft longitudinal axis. The conical cutter member being coupled to the rotary shaft so as to be rotated about the rotary axis by the shaft, upon the shaft's rotation about the longitudinal axis.

Abstract: A fixture is used to mount an angled machine head on a machine tool. The fixture includes a base adapted to be mounted on the machine tool, and a collar for holding the angled machine head. The collar is mounted for rotation on the base and allows the angled machine head to be rotated to any of a plurality of rotational positions. The collar may be selectively locked to the base to fix the position of the angled machine head.

Abstract: In an operating head, a tool assembly is provided with an inlet shaft engaged on an electrospindle and pivotally engaged through a corresponding containing casing, which is oriented about a longitudinal axis of the electrospindle by means of an electric motor coaxially mounted to the axis and provided with a rotor coupled in an angularly fixed manner to the casing itself.

Abstract: When a horizontal shaft and a piston are caused to travel to a first side with a gear coupling engaging, the revolution of the piston is designed to be restricted by meshing a spur gear with an internal gear fixed to a main body of a horizontal swivel part. On the other hand, when the horizontal shaft and the piston are caused to travel to a second side and the gear coupling thus disengages, the horizontal shaft and the piston are designed to be revolved in an integrated manner by meshing spur gears respectively with other spur gears. When the horizontal shaft and the piston travel from the first side to the second side, the spur gear is designed to be spaced away from the internal gear after the spur gear meshes with the spur gear.

Abstract: A milling head has a body, a holding device, a driving axle, a spraying device and a tool adaptor. The body has a base, a rear cover, a front cover, a bearing seat and a middle liner ring. The holding device is connected to the body and has a linking arm, a mounting jacket, a bottom cap, a positioning shaft and a locating spring. The driving axle is rotatably mounted in the body and has a transmission shaft and a driving bevel gear. The spraying device is mounted on the base and has a mounting cover and an spraying ball. The tool adaptor is rotatably mounted in the base below the spraying device and has a transmitting bevel gear, a holding head and a connecting segment.

Abstract: A right angle, modular machining head can be removably mounted on the too head of a CNC machining center to provide contour machining of a work piece around a C-axis. The modular head includes a rotating drive that moves the tool around a contour axis, producing nutational motion allowing close contouring of a work piece. The tool can be powered by a driven spindle on the tool head, or by a motor carried within the modular head. A locating connection between the modular head and the tool head, in combination with a position signals produced by a rotary encoder on the modular head registers the exact position of the tool within the coordinate reference system used by the machining center control system.

Abstract: A chamfering air tool includes a driving shaft in a casing rotated by air pressure, a rotary shaft perpendicularly combined to the driving shaft for rotation, and a cutter fixed to the rotary shaft. Air holes are formed through the rotary shaft in a longitudinal direction. An air discharge groove is formed in the cutter, and a hole communicated with the air hole is formed in a fixing bolt head. An air path is formed in the fixing bolt head to keep a predetermined gap from the cutter. A guide ring having a diameter approximate to a lower end of the cutter is rotatably mounted to the fixing bolt head. Thus, air is blown to the air hole of the rotary shaft, the air hole formed in the fixing bolt head, the air path formed between the cutter and the guide ring, and the air discharge groove of the cutter, thereby eliminating cut chips and cooling the cutter.

Abstract: An offset base router includes an offset base assembly comprising a base coupled with a sub-base which provides an offset center of gravity and an aperture through which a bit may access a work piece. Additionally, the base and sub-base allow a dust collection system to be attached through them. The offset base router further includes a motor assembly comprising a motor casing which houses a motor. The motor assembly connects with a gear assembly comprising an inner gear casing which is housed in an outer gear casing that includes a grip. The inner gear casing houses an arbor assembly that connects with the bit and the motor. A height adjustment assembly coupled with the offset base assembly and the inner gear casing allows a user to adjust the height of the inner gear casing relative to the base and the sub-base.

Abstract: An operating head for automatic machine tools of the type mounted on a structure for moving along a set of three Cartesian axes having a first support, fitted to the structure for rotation around a first axis, and a chuck unit fitted to the first support, wherein the chuck unit is interchangeable and projects from the first support, and is designed to allow angular positioning around a second axis orthogonal to the first axis. The first support includes a power transmission system for the chuck unit. The connection of the chuck unit to the first support permits changing from rough to finish work by simply replacing the chuck unit, rather than replacing the entire operating head.

Abstract: The invention relates to a tool head with a spindle bearing arrangement The bearings (9, 10) of said arrangement rest with one of their bearing shells on a driven spindle (2) with a tool holding fixture (1). With their other bearing shell they interact with a housing (8) in such a manner that in at least one part (10) of the bearings (9, 10) the respective other bearing shell interacts with a sliding piece (11) which is slideable along the housing (8) in the one sliding direction and which locks the spindle (2) with the housing (8) in a locking position. In the other sliding direction, said sliding piece releases the spindle in a release position. The invention provides a universally useful tool head by the following configuration: The respective other bearing shell of the one part (10) of the bearings (9, 10) is at least partially enclosed by the sliding piece (11). Said sliding piece (11) is forced into the locking position with a predetermined contact force by a drive device.

Abstract: A right angle drive arrangement for attachment to a vertical milling machine to permit the vertical milling machine to be utilized with a tool disposed on a horizontal output axis. The drive comprises a right angle housing, a coupling for attachment to a vertically disposed rotatable spindle on the vertical milling machine. A first bevel gear is in vertical rotational alignment with the spindle and supported in the right angle housing. A second bevel gear is in horizontal alignment with respect to the right angle housing. An output shaft is attached to the second bevel gear for supporting a tool thereon, for use with a tool to horizontally work a material by the vertical milling machine.

Abstract: A horizontal cutting type-tapping machine has a vertically extending drive shaft and a pair of detachably engaged surface gears. The surface gears have a curved upper surface gear, fixedly connected to the drive shaft, and a lower surface gear. A gearbox is connected to the lower surface gear and converts a horizontal rotating force of the drive shaft to a vertical rotating force. An externally threaded shaft is horizontally mounted to a vertically rotating gear of the gearbox. An internally threaded sleeve is disposed in the gear housing of the gear box and engages the externally threaded shaft so as to be horizontally moved by rotation. A saw part is fixed to a front end of the internally threaded sleeve. An internal tube, mounted around the drive shaft, has a thread at its upper portion and a lower portion with a diameter smaller than that of the upper portion. A vertically moving sleeve is slidably mounted around the lower portion of the drive shaft.

Abstract: An adjustment and/or alignment arrangement positions a toolholder (10) relative to a toolholder mounting (12) in machine tools in a pivot movement. An adjustment part (30) cooperates with a setting part (32). The setting part (32) is provided with a mounting housing (40), in which, counter to the effect of an accumulator (34), a guiding part (36) for the adjustment part (30) is guided longitudinally slidably. The guiding part (36) can be controlled by an operation part (38). The adjustment and/or alignment arrangement is of simple construction, and consequently, is of low cost, while to a great extent facilitates the desired adjustment simply and operationally securely.

Abstract: An angle spindle attachment includes a spindle shaft 21 for mounting a tool detachably, a housing 20 for mounting the spindle shaft rotatably such that the spindle shaft is oriented to a different direction with respect to the drive shaft 3 of the spindle unit, a gear train for transmitting the drive power of the spindle unit to the spindle shaft of the angle spindle attachment. a collet means 29 for retaining and releasing the tool that is movable between a position for retaining the tool and a position for releasing the tool so as to interlock the rotation of the spindle shaft, and a switching means 24,16 for switching the collet means between a operative condition to permit the tool to be retained and released and an inoperative condition for mounting the tool undetachably.

Abstract: A woodworking machine, in particular a trimming machine, of working elongate workpieces such as timbers, beams, boards and the like is proposed, the workpiece resting on a support and a longitudinally movable coupling element guiding the workpiece to working units. In this machine there is provided a guiding element which is likewise longitudinally movable and can be positioned in such a manner at a working unit that, on the one hand, optimal workpiece guidance is achieved and, on the other hand, the coupling element and the guiding element remain outside the operative region of the working unit.

Abstract: A structure for detachably mounting a horizontal drill head 5 on a drill head 4 including a driving spindle 10 rotatably driven by a driving means, a head case 2 for holding the driving spindle 10 above a work table 26 on which a work or works “W” are placed, and an advancing/retracting means for moving the driving spindle 10 toward and from the work table 26. The horizontal drill head 5 has a driving shaft 1 that is connected to the driving spindle 10 and horizontal drills 29 which are arranged substantially perpendicular to the axial direction of the driving shaft 1. The horizontal drill head 5 is mounted on the drill head 4 via a guide pin 7 slidable within a bearing 6 that is mounted on a sidewall of the head case 2 along a direction parallel to the advancing/retracting direction of the driving shaft 1.

Abstract: A machine tool comprises a base with an upstanding column, a vertical spindle axis tool driving unit symmetrically located and vertically movable on the front of the column, a frontwards oriented horizontal spindle axis tool driving unit symmetrically located and vertically movable extending through the column, and a pair of guiding rails to extend vertically thereon and horizontally spaced apart from each other for guiding the upward and downward movement of the tool driving units. Symmetrically disposed counterbalance weights for both tool driving units are located within the column. Independent leadscrew driving means provide vertical upward and downward movement of the tool driving units.

Abstract: A CNC milling machine comprises a main transmission shaft driven by a motor, an upright shaft provided with a transmission wheel set that is actuated by the main transmission shaft, an engagement device having a main shaft which is provided with a connection member which is in turn provided with an engagement wheel set engaged with the main transmission shaft, and a horizontal shaft provided with a gear set mounted thereon such that the gear set is engageable with the main shaft of the engagement device. The upright shaft is actuated to turn via the transmission wheel set so as to enable an upright milling cutter of the upright shaft to carry out the longitudinal cutting of a workpiece. The horizontal shaft is actuated to turn via the engagement wheel set so as to enable a horizontal milling cutter of the horizontal shaft to carry out the horizontal cutting of the workpiece without having to transfer the workpiece.

Abstract: A working machine includes a base having a working table for supporting a work piece and having a tool disposed on top for moving downward to machine the work piece. A block is secured to the base and has another tool for being selectively rotated to machine the side portion of the work piece. The another tool may be selectively driven by a motor which may drive the tool for moving downward to machine the work piece. The block has a screw driven slide to engage with the track and includes two followers for allowing the block to be secured to different vertical tracks.

Abstract: An angle spindle attachment for a vertically movable spindle unit is provided for rotating a cutting tool in a generally horizontal orientation. The attachment includes a spindle assembly having a drive train that is mechanically independent from the drive train of the vertically movable spindle unit, and a connector block for detachably connecting the spindle assembly at a transverse angle with respect to the vertically movable spindle unit. The connector block may include an angular adjustment mechanism that allows the spindle assembly to be oriented at an angle above or below the horizontal, as well as a rotational adjustment assembly that allows the spindle assembly to be pivotally adjusted about the axis of rotation of the vertically movable spindle unit.

Abstract: A machine tool to machine a workpiece including linear slide blocks supported one by the other on a pedestal to present a mounting surface for supporting a workpiece, a support head including a rotary indexing table that in turn supports an elongated cutter bar the support head to define an outwardly projecting cantilever end portion that is in turn supported by an outboard support, a cutter tool supported for rotary movement about an axis transverse to the extended length of the cutter bar, a drive means extends along the cutter bar for rotating the cutter tool and a collet chuck for engaging the cutter tool located remote to bearing seats to prevent radial distortion of such bearings when the cutter tool is engaged.

Abstract: A machine tool extension joins a machine tool to a spindle on a milling mine. The machine tool extension has an extension collar with a cavity therethrough and a mouth at either end for joining the collar to the milling machine and the machine tool. An extension shaft is disposed within the extension collar for mounting on the spindle. The shaft has a bar aperture extending axially therethrough. A draw bar is disposed within the bar aperture for holding the machine tool against the extension collar and shaft. The machine tool extension allows machining of parts with deep cavities.

Abstract: The tool holder of modular construction of driven tools for use on lathes consists at least of one base holder and various tool heads connectable interchangeably therewith. The base holder has a fixing shank, an attachment flange connected thereto, as well as a drive shaft rotatably mounted therein. Each tool head has at least one rotatable tool receptacle in a housing and a drivable shaft connected thereto. On the mutually facing ends of the drive shaft and the driven shaft there are provided coupling parts which can couple without relative rotation therebetween. The driven shaft is provided on the input side with a support pin freely projecting beyond the associated coupling part. The drive shaft is provided in the region of the attachment flange with a coaxial support bore, into which is received the support pin of the tool head.

Abstract: A machine tool to machine a workpiece includes linear slide blocks supported one by the other on a pedestal to present a mounting surface for supporting a workpiece, a support head includes a rotary indexing table that in turn supports an elongated cutter bar the support head to define an outwardly projecting cantilever end portion that is in turn supported by an outboard support, a cutter tool is supported for rotary movement about an axis transverse to the extended length of the cutter bar, a drive means extends along the cutter bar for rotating a cutter tool. The drive to rotate the tool in one embodiment takes the form of a belt extending between pulleys one of which drives the tool and the other is coupled to the electric motor in the drive head. A hydraulic motor is mounted in the cutter bar to rotate a tool according to a second embodiment.

Abstract: A method of and apparatus for forming a through bore or recess in a turbine blade, for a lacing wire hole for example, includes a machine capable of approaching the area to be machined in a first direction during which an initial machining operation may take place and them moving in a second direction completing the machining operation. Support means are provided to ensure the blade is held firmly. The method and apparatus permit of accurate machining of blades when they are in an array of blades still secured to the rotor.

Abstract: Disclosed is a structure of a turret head provided with turning tool mounting mechanisms and revolving tool mounting mechanisms on the turret, wherein a turning tool can be mounted on the revolving tool mounting mechanism rotatably mounted on the turret. The turning tool is mounted on the turret at a holder of the tool for positioning and at the same time is tightly affixed to the revolving tool mounting mechanism at the tapered portion of the tool.Also provided is an engaging and disengaging mechanism for engaging and disengaging a gear of a unit drive shaft relative to a gear of a revolving tool mounting mechanism in preparation for mounting a revolving tool different in direction.This feature enables a revolving tool different in direction to be driven.Another feature is a provision of a lock gear. Locking the lock gear allows the revolving tool mounting mechanism to be employed for turning tools. The revolving tool mounting mechanism can be used for revolving tools when the lock gear is unlocked.

Abstract: An apparatus is provided for transmitting rotation about and translation along a first axis from a driver to a toolholder with a spindle along an axis non-parallel from the first axis. A shaft is rotatably mounted within a sleeve which is slidably mounted within a bore along the first axis. The sleeve has an inclined surface at one end which when the sleeve is translated engages an interface member to provide displacement.

Abstract: A quick change right angle drill head incorporates mechanism rotating components within the drill head housing thereby resulting in a more compact package which facilitates use in space-limited locations. A single push button release enlarges a chuck opening to receive a cutting tool. An internally located compression spring becomes operative when reverse thrust forces are exerted against a cutting tool. The design of the present invention may be constructed to either lock the cutting tool into the drill head chuck or release it, upon exertion of the reverse thrust forces.

Abstract: A right-angle drive for a vertical milling machine to enable an operator to perform delicate horizontal work including a housing for attachment to a vertical milling machine with the housing including a horizontally displaceable rotating drive shaft to permit horizontal movement of the drive shaft instead of the bed of the milling machine during horizontal machining operations on the vertical milling machine.

Abstract: This invention relates to a universal tool rest for a milling planer and in particular to one mainly including two housings which may be rotated with respect to each other and three transmission shafts whereby the milling cutter thereon may be rotated in position with the tool rest so as to permit cutting of an inclined surface.

Abstract: A drive unit for a rotary tool, which unit includes a housing, a drive shaft mounted in the housing for transferring rotational drive force from a rotary drive to the tool, and a clamping mechanism mounted in the housing for generating a tool clamping movement along the axis of the drive shaft. The drive shaft is a hollow shaft, the clamping mechanism includes a pull rod mounted in the drive shaft and coaxially positioned relative to the drive shaft, the pull rod being mounted to be axially displaceable and fixed against rotation relative to the drive shaft, and the unit further includes a blocking device operative between the drive shaft and the housing for permitting the drive shaft to rotate relative to the housing only when the drive shaft is coupled to the rotary drive.

Abstract: A milling and drilling head for a machine tool has an input shaft housed in a stationary case also incorporating a control means drivingly connected to a ring gear which is fast with a moving case portion accommodating at least one tool holding spindle driven off the master spindle of the machine tool and being set at an angle to the X-axis thereof.

Abstract: An apparatus for connection to a machine tool having a rotating head and a fixed part is capable of automatically moving a cutting tool radially while a spindle carrying the cutting tool rotates. The apparatus includes a body which is engageable to the tool machine so as to remain fixed with respect to a central axis. A spindle is rotatably mounted to the body and is connected to the head of the tool machine for rotation. A slide holder is fixed to the spindle and carries a toolholder for sliding movement in a radial direction with respect to the central axis. An electric motor is mounted in the non-rotating body and drives a gear train which can radially move the toolholder while the spindle, slide holder and toolholder rotate. A position transducer is engaged with the electric motor for determining its position and thus the position of the toolholder on the spindle.

Abstract: The tool head of the cross slide of a lathe comprises a tool head housing, which is mounted in a body of the cross slide and angularly adjustable relative to said body, and a tool spindle, which is rotatably mounted in said housing and operatively connected to a drive spindle by an angle drive. To increase the range of operations by which a workpiece can be machined, the tool head housing is mounted in said body so as to be angularly adjustable on the axis of the drive spindle, which is at right angles to the longitudinal axis of the lathe, and the tool head housing is adapted to be coupled to the drive spindle or to the tool spindle.

Abstract: A horizontal drilling and milling machine having a horizontal, rotatable work table and an angle-cutting milling head with a milling spindle and a drive shaft which is driven by the drilling spindle of the headstock. The milling head is rotatable about the axis of the drilling spindle, and can be pivoted into a tool exchanging position about an axis which extends at right angles to the axis of the drilling spindle.

Abstract: The head of a plano-milling machine has two jointly rotatable, perpendicularly-related collet spindles journalled on bearings in a box-like housing which can be mounted on the slide of the machine so as to be indexable about the axis of the vertical collet spindle to present the horizontal collet spindle to different vertical faces of a workpiece.The head is journalled to the slide by a combined indexing means and hydrostatic bearing which includes means to lock the head in a chosen angular position. Provision is made for numerical control and automatic tool changing.

Abstract: A spindle which may be connected to machine tools, taking power from a rotating power shaft of the machine for advancing and retracting a rotating tool at right angles to the power shaft of the machine. The spindle has a rearward uniform diameter screw which projects through a feed nut and into a hollow headstock. The feed nut has threads engaging the threads of the screw, together with an adjacent hollow section which seats an annular thrust bearing, as well as a rear collar of the headstock which constrains the headstock to move with the feed nut. Power is transferred to the headstock by means of a rotating quill, coaxial with the screw, but axially constrained within a housing. The quill is provided with a lengthwise keyway which is colinear with a similar, but much longer keyway in the headstock. The headstock is able to axially slide back and forth through the quill as the headstock is pushed and pulled by the feed nut moving on the screw.

Abstract: For facilitating the rotating of a tool-receiving device, in particular an angled milling head, an elongated bushing which is concentric with respect to the milling spindle axis is secured in the milling spindle carriage. The bushing has at its free (lower) end a conical receiving opening. A support sleeve is rotatably supported in the bushing by means of radial and axial bearings. The support sleeve has at its free (lower) end a fastening flange for the tool-receiving device. Above the fastening flange is provided a centering cone conforming in shape to and fitting into the conical receiving opening. An oil film is interpositioned between the opening and the centering cone to provide a uniform support for the support sleeve. The milling spindle is supported in the support sleeve. By means of a ring gear, which is driven by a servomotor, it is possible to rotate the tool-receiving device about the axis of the milling spindle into predetermined angular positions.

Abstract: A swivel head swivels on its support along a plane face that is perpendicular to the axis of rotation. The face has the shape of a movable disk that slides on a stationary disk. The movable disk is rotated by means that ensure centering with a predetermined clearance. The stationary disk is pierced by two diametrically opposite bores and the movable disk is pierced by at least one pair of diametrically opposite bores with the same diameter and with the same distance between centers, and located at the same distance from the center, within the clearance. The positions of a pair of bores may be generated from those of another pair, by rotation of predetermined angle. The support features means for inserting, across the two disks, two expandable rings, for expanding them, and for retracting them.

Abstract: An adaptor for a tooling attachment employs a hydraulically actuated sleeve clamp which secures an adaptor sleeve to the spindle housing of a machine tool, the attachment being affixed to the sleeve. A coupling assembly permits locking the adaptor sleeve at selected angular positions relative to the spindle housing, indexing of the sleeve being accomplished through the use of a pinion drive and an indexing gear. Indexing of the adaptor sleeve is permitted by a clamp mechanism which engages a circumferentially extending slot of the adaptor sleeve and which causes engagement and disengagement of the coupling assembly.

Abstract: A machine tool having an automatic tool changer for transferring tools between a tool magazine and a horizontal tool spindle rotatably mounted in a spindle head and which includes a vertical head which rotatably carries a vertical tool spindle and a horizontal drive shaft connected thereto is removably mounted on a vertical head support. In advance of a machining operation on a top surface of a workpiece, relative movement between the vertical head support and the spindle head is effected in a vertical direction and first and second horizontal directions, so that the vertical head is mounted on the spindle head, with the drive shaft being drivingly connected with the horizontal tool spindle. A tool support station mounted on the vertical head support is provided with two tool grippers each for vertically holding a tool.

Abstract: A machining center for machining the interior of an elongate tubular workpiece includes a bed on which a rotatably indexable member is slidably mounted for movement on the bed along a first axis. Removably fastened on the indexable member in spaced parallelism are a first and second hollow bore spindles each engaging the exterior surface of a tubular workpiece whose interior is to be machined. The first spindle is rotatably driven to rotate the tubular workpiece about its axis responsive to machine tool control system commands slidably mounted on the bed for movement thereon along a path perpendicular to the path of member movement in an upright. Extending from the upright parallel to the axis of upright movement for insertion into the workpiece bore is an arm which is movable along the upright along a vertical direction. At the distal end of the arm is a right angle, high speed rotary driven cutting tool carrying spindle.

Abstract: An apparatus for centering and indexing of milling machine parts, in particular angle milling heads on a spindle carriage of a milling machine. Cooperating indexing elements are arranged on the angle milling head and on the spindle carriage, which elements are simultaneously also the centering elements. These are constructed as four similarly constructed aligning units which are arranged offset to one another each at 90.degree. in peripheral direction. Each aligning unit consists of an aligning tab arranged on the one milling machine part, preferably the angle milling head and a fixing piece provided on the other milling machine part and has a groove therein. The angle milling head can be fixed in predetermined angular positions relative to the spindle carriage through the aligning units.

Abstract: A drilling machine comprises a ram movable up and down on a carriage slidably mounted on a horizontal crossrail. A toolhead is mounted on the bottom end of the ram for pivotal movement about a horizontal axis at right angles with the crossrail and is pivoted to a desired angular position by a first drive shaft within the ram via bevel gearing. Rotatably mounted in the toolhead for rotation about an axis lying in a vertical plane is a toolholder which rigidly supports a drill and which is driven from a second drive shaft within the ram via bevel gearings. Preferably, the machine further comprises a rack-and-pinion mechanism driven from the second drive shaft for securely but releasably locking a turning tool at the bottom end of the ram, so that the machine can be used also for turning operation as a workpiece is rotated on a turntable. This turntable is of course held stationary during drilling operation.