Abstract: Machine tool with a workpiece receptacle for receiving a workpiece to be machined and with a tool receptacle for receiving a tool that is needed for machining a workpiece. A hardness measuring device is integrated in the machine tool, and a hardness measurement can be carried out in an automated manner at the workpiece by the hardness measuring device.

Abstract: The invention relates to a device to position and align a rotationally-symmetrical body (28) with respect to a measuring device (19) for the implementation of a measurement on the rotationally-symmetrical body (28), having a basic element (24) which has a contact surface (22) on a pin (23) or is allocated to a contact surface (22) on which the rotationally-symmetrical body (28) is supported for the implementation of the measurement, wherein a positioning element (41) which can be moved relative to the contact surface (22) is provided on the basic element (24), said positioning element (41) comprising a prismatic receiver (64), wherein the contact surface (22) is positioned within the prismatic receiver (64) or abuts on this and a movement path of the positioning element (41) towards the basic element (22) corresponds at least to the height of the prismatic receiver (64).

Abstract: A machine tool including a tool magazine (20) arranged in a storage region adjacent to a working region of a workpiece to store a working tool (31) for working the workpiece and a measurement tool (32) for measuring the workpiece; a spindle (10) to which the working tool and the measurement tool are attached in a detachable manner, the spindle being provided in a movable manner relative to the workpiece; a shutter (40) provided between the working region and the storage region in an openable and closable manner; a transceiver (51) attached to the measurement tool; and a communication module (52) arranged in the storage region to communicate with the transceiver of the measurement tool attached to the spindle.

Abstract: An apparatus for endpoint detection during removal of material from an electronic component includes a mounting plate operable to provide physical and electrical attachment for a device-under-test (DUT), a spindle operable to hold a tip for removing material from the DUT, a signal generator operable to provide an input signal to a first electrode, and a microprocessor connected to use an output signal from a second electrode to terminate the removal of material when an endpoint is reached, the first electrode being one of the tip and the DUT and the second electrode being the opposite one of the tip and the DUT.

Abstract: A shape measurement data is acquired by measuring along a spiral measurement path a lens shape which is machined along a spiral machining path. An interpolated shape measurement data at intersecting points of a radial line passing through a center of the lens shape and the spiral measurement path is acquired by interpolating the shape measurement data, and a compensated machining amount for removing a machining error at each of the intersecting points (the machining points) is calculated from the interpolated shape measurement data by interpolation. Further, a machining point compensated machining amount at each of the machining points on the spiral machining path is calculated from the calculated compensated machining amount, and a compensated machining path is created on the basis of the machining point compensated machining amount.

Abstract: The invention relates to a machine tool having a cutting tool in order to monitor and if necessary to correct the dimensional accuracy of the workpiece during machining. To this end, a sensor (5) for sensing a dimension of the workpiece (10) to be machined during machining is provided.

Abstract: In a method for controlling a tool during machining a work piece using the tool, a first measuring arrangement which has a first ultrasonic probe for emitting ultrasonic waves is used, the first measuring arrangement being arranged ahead of the tool with respect to the relative tool movement direction and being moved relative to the work piece in the relative tool movement direction. The ultrasonic waves emitted by the first ultrasonic probe are transmitted to the work piece, and are transmitted back to the first ultrasonic probe, by a first column of liquid which is created by the first measuring arrangement and situated between the first ultrasonic probe and the work piece for measurement. The measurements are used for automatically adjusting the position of the tool relative to the work piece during machining the work piece.

Abstract: A spindle control system for a milling machine is provided. The milling machine includes a column, an overarm, a spindle for mounting a cutter, a first motor mounted on the column for driving movement of the overarm, and a second motor mounted on the overarm for driving rotation of the spindle. The spindle control system includes a distance sensor and a temperature sensor, each to be mounted on the overarm and to be disposed proximate to the end portion of the spindle. The spindle control system further includes a central control unit for determining a compensation parameter based on the displacement sensed by the distance sensor and the temperature sensed by the temperature sensor, and for controlling movement of the overarm by the first motor through a compensation distance based on the compensation parameter to compensate for at least one of the cutter deformation and the spindle deformation.

Abstract: To increase precision in straightness on a journal thrust surface relative to an outer peripheral surface of a journal in a crankshaft, a control system is provided for controlling movement of a cutter in axial directions by running a control program transferred from an automatic programming apparatus. The automatic programming apparatus corrects machining data on the basis of data for correcting the straightness gained through a comparison between results of a measurement of machining dimensions of the journal thrust surface in the workpiece on which a cutting process has been carried out and target machining dimensions for the journal thrust surface. A control program is prepared on the basis of the corrected machining data after correction of the machining data.

Abstract: A method and apparatus are provided to machine a curved surface such as an inner or outer peripheral surface of a pipe. The pipe is held stationary during machining and a rotatable spindle of a machine head moves along multiple orthogonal axes to align the rotational axis of the spindle with the longitudinal pipe axis. Preferably, the pipe axis is located by using a touch probe to engage the curved surface at multiple spots and the calculating the location of the pipe axis. The cutting tool, which is preferably a cutting tool insert, is rotated by the spindle to machine the curved surface.

Abstract: The present invention provides a high dynamic performance mounting technique that is suitable for mounting sensor elements in adverse environments. According to one aspect, the present invention includes a kinematic mounting technique for a movable secondary mirror in an optical sensor. According to another aspect, the invention includes a mounting structure that provides deterministic alignment of a sensor element over multiple positions. According to another aspect, the invention includes a mounting technique with high dynamic performance yet minimizes sensor obscuration. According to another aspect, the invention includes a mounting technique that decouples actuator stiffness and mounting accuracy from the overall dynamic stiffness and alignment accuracy of a movable secondary mirror in an optical sensor.

Abstract: The invention relates to a method of machining the bearing seats of main and rod bearings (HL, PL) of crankshafts (1), in which the bearing seats (30) of the main and rod bearings (HL, PL), after the primary forming of the crankshaft (1) by forging or casting, are subjected to the following processing operations: forming by machining with a specific cutting edge, deep rolling all fillets or recesses of the main and rod bearings, straightening of the crankshaft (1), precision machining with an end-milling cutter (12) in each case by high-speed roughing-cut turn-milling and finishing-cut turn-milling, smooth rolling of the bearing seats of the crankshaft after the finishing-cut turn milling, wherein the roughing-cut turn-milling and the finishing-cut turn-milling is effected during in each case an essentially complete revolution of the crankshaft (1) without longitudinal feed and without tangential feed of the end-milling cutter (12)

Abstract: A fixture and method is provided for gripping an article, such as a sputtering target. The fixture comprises a base, a first set of contact rollers, and a second set of contact rollers, wherein at least one of the first set and the second set are adjustably positioned relative to the other of the first set and the second set on the base. The contact rollers can be configured as v-grooved wheels that will only touch chamfered portions of an outer diameter of the sputtering target when the contact rollers are clamped against the sputtering target. At least one of the first set and the second set of contact rollers can be pivotally mounted on a slide, with the slide being adjustably positioned on the base of the fixture.

Abstract: In a method for controlling a tool during machining a work piece using the tool, a first measuring arrangement which has a first ultrasonic probe for emitting ultrasonic waves is used, the first measuring arrangement being arranged ahead of the tool with respect to the relative tool movement direction and being moved relative to the work piece in the relative tool movement direction. The ultrasonic waves emitted by the first ultrasonic probe are transmitted to the work piece, and are transmitted back to the first ultrasonic probe, by a first column of liquid which is created by the first measuring arrangement and situated between the first ultrasonic probe and the work piece for measurement. The measurements are used for automatically adjusting the position of the tool relative to the work piece during machining the work piece.

Abstract: A method for processing a screw rotor includes a step of rotating a blade holder 2 while shifting the blade holder 2 in X-axis, Y-axis, and Z-axis directions to form a groove on the outer surface of a rotating cylindrical workpiece 1 with a tool 3 using a processing apparatus having a bed 11; a C-axis shaft supporter 12 disposed on the bed 11; a C-axis shaft 14 held by the C-axis shaft supporter 12, the C-axis shaft 14 for rotating the cylindrical object 1; a column 13 disposed on the bed 11; the blade holder 2 rotatably held by the column 13; and the tool 3 attached to the blade holder 2.

Abstract: In a method of machining a blank from all directions using at least one machine tool, such as a milling machine, production of the ready-to-use, measured component which is controlled and classified with regard to quality, such as a turbine blade, occurs in as few steps and setups as possible with the use of machine tools and milling machines that as far as possible are of identical design. The blank, in a first machining step, is held by at least one first adapter and a first region is given its final partial shape corresponding to the intended use by a machine tool or milling machine. In a second machining step, the partly machined blank is held by at least one second adapter in the first, finally machined region, and the remaining region is given its final overall shape corresponding to the intended use by a machine tool or milling machine.

Abstract: A machine tool comprises: a workpiece spindle (12) having an electromagnetic chuck (18) provided on an upper end thereof for clamping a workpiece (W), and extending along the Z-axis; a tool magazine which accommodates a tool (T) and a centering jig (20); an automatic tool changer (17) for exchanging the tool (T) between the tool magazine and a tool spindle; and a run-out measuring device (19) for measuring a run-out of the workpiece (W) placed on the electromagnetic chuck (18); wherein a workpiece correction distance is calculated on the basis of the run-out of the workpiece (W) measured by the run-out measuring device (19) before the workpiece (W) is clamped by the electromagnetic chuck (18), and a workpiece centering operation is automatically performed by the centering jig (20) attached to the tool spindle until the run-out of the workpiece (W) falls within an allowable range.

Abstract: A portion (14a, 14b) of a chip remover (14) is defined to be vibratory to give an NC machine tool (MT 1) a vibration transferable onto a surface (FS) of a work (13) under a finishing by the NC machine tool (MT1), a decision is made whether the NC machine tool (MT1) enters the finishing, and vibration of the vibratory portion (14a, 14b) is controlled, as the decision is true. A chip removal method and an NC machine tool equipped with a spiral chip remover (113) as a chip remover have various chip removal rules for determining permission/prohibition of the operation of the spiral chip remover (113). This spiral chip remover (113) operates based on commands described in a machining program. When a command in the machining program is executed, the permission/prohibition of the operation of the spiral chip remover (113) is controlled according to the chip removal rules.

Abstract: In a finishing apparatus, a plurality of works are retained at distances from each other in a direction of an X-axis. A single spindle is disposed on a table movable in the direction of the X-axis, the spindle has an axis parallel to an axis of each of bores to be finished, and is capable of being advanced and retracted axially. A measuring device is provided that measures an inside diameter of each finished bore and which is advanced and retracted independently from the spindle in a direction along the axis of each finished bore. A combination tool is mounted at a tip end of the spindle and finishes an inner surface of any of the bores to be finished, even if the position of insertion of the combination tool into each of the bores is changed.

Abstract: A process for edge-machining an optical (spectacle) lens including preliminary machining of an edge of the lens rotatable in controlled manner about a rotational axis of a workpiece by a first edge-machining tool adjustable radially relative to the rotational axis of the workpiece, whereby the lens is given a circumferential contour which corresponds to the circumferential contour of a lens holder apart from a slight degree of oversizing, contactless measurement of the preliminarily machined lens edge, and finish-machining of the lens edge, taking account of the detected edge data of the preliminarily machined lens, by means of a second edge-machining tool adjustable radially relative to the rotational axis of the workpiece, whereby the lens is provided with a circumferential contour substantially complementary to the circumferential contour of the lens holder.

Abstract: A method and system for machining a cylinder head include loading a cylinder head into a first five axis computer numerically controlled (CNC) machine. A first fixture of the first CNC machine is then located against a top surface of the cylinder head such that the cylinder head is in a horizontal position. The first CNC machine then machines the cylinder head in the horizontal position. A second fixture of the first CNC machine is then located against a bottom surface of the cylinder head such that the cylinder head is in a vertical position. The first CNC machine then machines the cylinder head in the vertical position. The cylinder head is then moved into a second five axis CNC machine. A fixture of the second CNC machine is then located against a bottom surface of the cylinder head. The second CNC machine then machines the cylinder head.

Abstract: An arrangement performs a contact pattern test of bevel gears when they are produced. The arrangement includes a testing unit in connection with a machining apparatus, to which testing unit a finished bevel gear can be fastened to rotate around its axis so that the finished bevel gear and the other bevel gear which is being finished can be arranged into a rotating contact with each other so as to allow the contact pattern of the cogs to be checked.

Abstract: In a plural-roll rolling mill having a pass line arranged by the respective sets of rolls, each having a caliber formed on the outside peripheral surface thereof, the outside peripheral surfaces being disposed close to each other, the calibers of the rolls being cut with a cutting tool of a three-dimensionally (forward and rearward, rightward and leftward and upward and downward) movable cutting machine. The rolling mill, which has a reference column disposed on the outside surface thereof at a position spaced apart from the pass line by a predetermined distance, is removed from a rolling line and fixed, and the positional alignment of the cutting tool is carried out by causing a contact sensor disposed on the cutting machine at a position spaced apart from the cutting tool by a predetermined distance to come into contact with the reference column. With this arrangement, there are provided a method and apparatus capable of cutting the rolls of the plural-roll rolling mill while mounted on the rolling mill.

Abstract: A modular vehicle includes a plurality of modular members arranged on a base. The modular members collectively approximate the contour of a vehicle interior or exterior. The modular members are arranged on the base in a close fitting, removable fashion. Each of the modular members has a contoured surface which closely approximates a corresponding portion of a contour of a vehicle interior or exterior. The model vehicle can be reconfigured by simply removing the modular members affected by a design change, reconfiguring the removed modular members and replacing the removed modular members. In another feature, the model vehicle assembly includes a plurality of floor section modular members, wherein one of these floor modular members has a hole defining a reference point. A digitizer which measures the contour of the interior is mounted in the hole. A method of assembling a model for a vehicle is also disclosed.

Abstract: A mounting device for a telescopic ball-bar has a hexagonal shank retained in jaws of a chuck on a spindle of a lathe. A supporting bracket extending from the shank carries a magnetic socket in one of a plurality of locations, and receivably mounts one end of the ball-bar for universal pivotal motion. The configuration of the bracket, the spacing between the socket and the shank, and the orientation of the socket, are such that the other end of the ball-bar, which is universally pivotally mounted to the tool post of the lathe, may execute a circular trajectory of greater than 180.degree., which trajectory intersects the axis of rotation of the lathe.

Abstract: A lathe capable of performing both usual machining and balance correction machining of a workpiece. In a combined machining lathe having a drilling and/or milling machine, vibration sensor(s) are attached to a headstock and/or a tailstock and a sensor for detecting a rotation angle of a main spindle is provided. After the usual machining, the workpiece is rotated at a predetermined rotating speed on the same lathe and an amount of imbalance and phase are calculated by a imbalance arithmetic unit. An NC machining program for balancing the workpiece is automatically produced by a balance correction machining program producer within a numerical controller and balance correction machining of the workpiece is carried out using a rotary tool such as a drill or the like.

Abstract: A method for measuring the contour of a machined part with a contour gage apparatus, having a probe assembly including a probe tip for providing a measure of linear displacement of the tip on the surface of the part. The contour gage apparatus may be moved into and out of position for measuring the part while the part is still carried on the machining apparatus. Relative positions between the part and the probe tip may be changed, and a scanning operation is performed on the machined part by sweeping the part with the probe tip, whereby data points representing linear positions of the probe tip at prescribed rotation intervals in the position changes between the part and the probe tip are recorded. The method further allows real-time adjustment of the apparatus machining the part, including real-time adjustment of the machining apparatus in response to wear of the tool that occurs during machining.

Abstract: A connecting device for connecting a shank 16 to a measuring probe 18 is disclosed, to enable the probe 18 to be incorporated on a machine tool for the purpose of tracing a contour of a model. The device includes first and second parts (20,22) connected to the shank and the probe respectively, retained together by a connecting bolt 50 which is spring-loaded by means of Belville washers 56. An arm 60 extends from the second part to engage the housing 14 of the spindle 10, and thereby prevent rotation of the spindle shaft 12. In the event of accidental spindle start-up the two parts 20,22 may rotate relative to each other (the shank rotating with the shaft 12); a thrust bearing 42 enabling sliding of the two parts.

Abstract: The invention relates to a sensor-system for metal workpieces, especially cast components (casting cleansing), and a cutting sensor for its implementation, and is intended to improve deburring quality rationally and effectively. To this end, relatively coarse burrs are cut off to a predetermined height and the remaining burrs and also the relatively small ones are removed by sensor control in a single pass by a combined tool having sensor cutter and a burr pre-cutter.

Abstract: A method and an apparatus for balancing a rotor, in which compensation points are distributed symmetrically on the rotor's circumference about the axis of the rotation, which compensation points are suitable for an imbalance compensation by means of a component revolving with the rotor and on its circumference having scannable structural elements, pulses are generated that provide information for the respective rotational angle position of the rotor for determining the imbalance angular position and for indexing the rotor after the imbalance measuring run into the compensation angle position, and this component may be embodied as a gear wheel or fan wheel.

Abstract: A probe device (10) for a machine tool includes a part sensing device (28) attached to the end of a piston rod (26), movable along a cylinder (12) mounted on the machine tool spindle head (14). The rod (26) is attached to a piston (42) that is air actuated to extend or retract the rod (26) to respectively move the sensing device (28) to a part measurement position outside the cylinder (12), or to a protected position within the cylinder. When the device (28) is in its measurement position the spindle had (14) is selectively moved to bring device (28) into contact with a machined part to determine the accuracy of machining.

Abstract: Methods and apparatus are provided for measuring cylinder head combustion chambers and for providing inputs to machines which can perform operations to assure that all combustion chambers are of a correct volume. Apparatus is provided for matching volumes in gear assemblies as well as for providing precise machining of gears, turbine blades and other parts. Measurements are probably made using electro-optical sensors, particularly of the traingulating type.

Abstract: A method is described for assuring concentricity of a gear's pitch circle with its axis, the pitch circle having a non-constant radius about the axis. The method comprises the steps of: determining the gear's pitch circle and its position of maximum radial offset from the gears axis; positioning the gear in a chuck having a plurality of simultaneously movable jaws, the chuck having an axis which is continually concentric with respect to its jaws as they move, the position of maximum radial offset being positioned adjacent a chuck jaw so that when the jaws are moved to grip the gear, the axis of the gear is offset from the chuck axis by action of the jaws on the gear; placing the chuck and gripped gear in a machine tool adapted to machine the gear concentrically with the chuck's axis; and operating the machine tool to remove sufficient material from the gripped gear to bring the gear's axis into concentricity with the gear's pitch circle.

Abstract: This invention relates to a machining center including a machine tool and a three-dimensional measuring machine. The machining center machines a workpiece and then measures the shape of the machined workpiece. The measuring machine includes a probe unit for measuring the shape of the machined workpiece on a table of the machining center. For effecting measurement, relative motion between the probe unit and the machined workpiece is achieved by the first to third drive means.

Abstract: A spark plug grinding machine is equipped with force sensors to measure grinding forces and other forces attendant to a grinding operation. Ceramic spark plug insulators are carried by spindles on a Ferris wheel into a grinding station. A control wheel engages and spins each part as a grinding wheel grinds the surface of the insulator. A three axis transducer on one of the spindles measures force components along the axis of the spindle, parallel to a tangent of the grinding wheel and in a radial direction. A torque sensor on the control wheel measures the torque as the wheel rotates each insulator. Either or both of the sensors may be used. They are coupled through slip rings to a recorder.

Abstract: The device, which controls operation of the loading magazine in an automatic machine tool and is capable of measuring the handling diameter of single workpieces fed into the machine, comprises a set of jaws located between the magazine and the automatic feed facility, and a transducer which monitors the distance separating the jaws when encompassing the workpiece and relays a corresponding information signal back to the unit which controls the operation of the machine tool as a whole.

Abstract: An apparatus and method for balancing a workpiece in which material is removed by advancing a drill, mill or the like into contact with the workpiece and thereafter removing material therefrom. A force transducer is coupled to the workpiece or tool holder to produce an electrical signal in response to the force resulting from contact between the tool and the workpiece to reliably and accurately indicate contact for zero depth reference of the material removing operation.

Abstract: The present invention relates to a method and apparatus for adjusting the weight of workpiece by twice machining a weight-adjustment portion formed on the workpiece. In the present invention, the same cutting tool is used for machining the weight-adjustment portion and the feeding position for the second machining of the weight-adjustment portion is determined in response to the weight of the workpiece after the first machining. According to the present invention, even if the tips of the cutting tool should wear because of prolonged machining operations and, as a result, the amount of the first machining is insufficient, the said insufficiency is compensated for by the second machining.

Abstract: A method and apparatus for the automatic balancing of workpiece having diverse surface geometry is disclosed. The balancing machine of the present invention provides for computer numerical controls in the balancing and material removal operations. The processes provide for alternative methods of material removal and further provides for the balancing operation to be self-calibrating and self-programming.

Abstract: Various techniques are disclosed for controlling the operation of a workpiece inspection procedure using a battery operated probe to contact the workpiece and transmit information back to a controller in a machine tool system. In one embodiment, battery power is applied to the probe transmission circuitry in response to a flash of infrared radiation. In another embodiment, the probe is turned on by touching the probe against a reference surface. In both embodiments, a timer is provided to automatically disconnect the batteries after a predetermined time period. In such manner battery life is prolonged.

Abstract: An apparatus and method for first drilling a hole in a workpiece by utilizing a locating jig, and then inspecting the hole to insure it is drilled to the proper diameter. There is an inspection device having an inspection probe that is pivotally mounted about a universal mounting device so that the lower inspection end of the probe is able to deflect laterally to fit in the drilled hole so as to be centered therein. This arrangement compensates for any misalignment in the positioning of the inspection apparatus relative to the earlier alignment of the drilling apparatus.

Abstract: A hardness tester for pipes comprising a positioning mechanism that presents the pipe to a multiple purpose testing head having a pre-programmed proportional control configuration that independently engages the pipe and determines the pipes relative position to that of the program controlled testing head which contains independent pre-programmed testing heads. The pipe is prepared for testing by cleaning a small test portion of the pipe, engagement of a load cell assembly to the clean pipe portion determining material hardness.

Abstract: An integrated factory system affords precision machining and inspection of aircraft turbine blades, as well as other metal parts having two generally opposite principal surfaces. It uses only two stages of chucking by the meltable matrix method. After embedding one of the surfaces in the first chuck, which positions the blank relative to a plane of reference, the other surface is machined and inspected according to programs relative to that plane. Without release from the first chuck, the part is transferred to a second chuck for embedding the machined principal surface relative to a second parallel plane of reference a precise distance from that of the first chuck. Machining and inspection is now completed relative to this second plane of reference. Improved matrix chucks are provided, as well as new chucking apparatus which establishes the planes of reference.

Abstract: A method of and apparatus for balancing a rotary body is disclosed. The apparatus includes an unbalance detection unit which rotates the body in first and second spaced bearings, the location of the first and second bearings defining first and second bearing planes, respectively. The forces developed by rotation of the body are sensed at the first and second bearing planes and the forces about the first bearing plane are summed to determine the weight and angular location of a mass compensation which, if effected, would substantially statically balance the body. An iterative technique is utilized which determines the axial location of the mass to be removed or added which would reduce to a minimum the dynamic unbalance of the body. The body is then passed to an unbalance correction unit which removes or adds the mass at the determined angular and axial locations to minimize the static and dynamic unbalances.

Abstract: A turret lathe having a part gaging probe at one position on the turret. The lathe has a probe cover supported in a holder when the probe is in use. The numerically-controlled lathe mechanism enables the turret to carry the probe over the cover to apply or remove the cover during the cycle of operations.

Abstract: Method and apparatus for measuring cylinder head combustion chambers and provide inputs to machines which can perform operations to assure that all combustion chambers are at a correct volume. Also disclosed are means for matching volumes of engine assemblies as well as precise machining of gears, turbine blades and other parts. Measurements are ideally made via electro-optical sensors, particularly triangulating types.

Abstract: A method and an apparatus for correcting the unbalance present in a rotor in one or several correction steps by adding or removing material only to or from given points on the rotating body on which only a limited quantity of material is available for correction, with the unbalance being resolved into components as given by the design of the rotor, with correction being carried out in one of several given components, and with the unbalance determined being eliminated in the given components as to the possibility permitting the least quantity of material to be added or removed in a minimum number of correction runs, so that finally an uninterrupted sequence of correction points is available on the rotor.

Abstract: A conditioning line for steel pipes in which steel pipes are transversely transferred to effect the end processing thread cutting, thread inspection, hydrostatic testing, etc., on the steel pipes. With a view to increasing the efficiency of the conditioning operations, a reprocessing line is arranged to run parallel to a main line such that the steel pipes rejected on the main line are automatically transferred to the reprocessing line where the rejected steel pipes are reprocessed and automatically transferred back to the main line.

Abstract: An improved grinding method and apparatus is advantageously used to sequentially grind the pins of a crankshaft. During the grinding of each crankpin, the pin is supported by a steadyrest. During an initial grinding operation, the crankpins are measured or gauged to determine if they are out-of-round by an amount which is greater than the tolerances for the finished crankshaft and less than a maximum amount. If a crankpin is out-of-round by an amount which is equal to or greater than a maximum amount, the crankshaft is rejected. However, if a crankpin is out-of-round by an amount which is less than the maximum amount and more than the tolerance for a finished pin, a second grinding operation is initiated after the initial grinding operation has been completed. During the initial and second grinding operations, a main drive motor is effective to press the steadyrest against the crankpins.