Abstract: The cylindrical peripheral surface of a rotating workpiece is ground by a first section of a rotating grinding wheel while a second section of the grinding wheel is used to simultaneously grind a thread into the peripheral surface so that the reduction of the diameter of the peripheral surface and the forming of a thread therein take place in one and the same operation. The two sections can constitute integral parts of a one-piece grinding wheel or two discrete spaced-apart components of a composite grinding wheel. The diameters of the freshly ground portions of the peripheral surface are monitored by a measuring head which transmits appropriate signals to a computer for regulation of the controls of the grinding machine so as to change the position of the grinding wheel relative to the rotating workpiece if the diameter of the ground portion of the peripheral surface deviates from a preselected value. The same measuring head can be used to ascertain radial deviations of the rotating workpiece.

Abstract: The internal thread of a rotary workpiece, especially a ball thread, is ground with a CBN grinding wheel whose axis makes with the axis of the workpiece a grinding angle smaller than the lead angle of the thread to be ground. The profile of the grinding wheel is thereupon corrected by a diamond profiling roll whose axis makes with the axes of the grinding wheel an angle larger than the lead angle.

Abstract: A profiling and dressing tool for grinding wheels which are used for the cutting of external threads has a diamond roll with a first circumferentially extending rib at one axial end and a second circumferentially extending rib at the other axial end. One of the ribs is used for preliminary profiling of the grinding wheel, and the other rib is used for final profiling and dressing. The tool can be used for the profiling and dressing of a wide range of grinding wheels having different diameters and grooves of different depths. One of the ribs is idle when the other rib is in use, and vice versa. If the grinding wheel is to be formed with a series of grooves alternating with ribs, each of the selected ribs of the diamond roll is moved radially of and toward the periphery of the grinding wheel, is thereupon extracted, moved axially of the grinding wheel, caused to plunge again into the material of the grinding wheel, and so forth until the profiling is completed.

Abstract: Poppets of lift valves are ground in a grinding machine wherein the chuck clamps the stem midway between the head and the foot of the poppet and is indexible through 180.degree. so as to place the foot into the range of a first portion of the working surface of a grinding wheel in one of its positions and to place the head into the range of another portion of the working surface of the same grinding wheel in the other of its positions. The entire working surface of the grinding wheel is dressed during grinding of the head, and the carriage for the spindle of the grinding wheel is moved in response to signals which denote the final position of the grinding wheel upon completed grinding of the foot. The chuck is indexible in a rotary work holder whose axis coincides with the axis of the clamped poppet and is normal to the axis about which the chuck is indexed by a rack-and-pinion drive.

Abstract: A method and apparatus for measuring the abrasion depth of an outer surface of a substantially stationary body such as a tool which rests in working position against a rotating body such as a shaft to be ground. A measurement pin is inserted in a first direction into a measurement sleeve arranged in the stationary body, displaceably in the sleeve by action of one end of the pin against the shaft. During the grinding operation as a result of the abrasion on the surface of the stationary body the measurement pin is gradually inserted further into the sleeve and upon exceeding a distance of insertion corresponding to a predetermined abrasion on the surface of the stationary body which requires replacement of the stationary body the other end of the measurement pin contracts against an electric contact disposed inside the sleeve so as to provide an alarm via an electric circuit of an indicating device. In a path detection system a desired reference length of an end length of the measurement pin is stored.

Abstract: The disclosure relates to a process for the continuous, automatic feed of at least one jaw of a steady for supporting a workpiece, for example a shaft or crank shaft with its axis in the desired position on grinding the workpiece outer face and is more specially with respect to a process in which a workpiece freely supported between two support units, as for example two centers, is acted upon by its own sagging force, the radial force of the tool, for example a grinding wheel, and other forces produced on machining the workpiece, which may be radial or tangential with respect to the axis. The disclosure is furthermore with respect to an apparatus for undertaking the process.