Abstract: A machine tool comprises a spindle unit for raising a spindle on which a cutting tool is mounted by a magnetic force and supporting the spindle. The spindle unit carries out feedback control so as to maintain the spindle in its target position in the radial direction. A feeder for feeding the cutting tool to a work comprises a servo motor for moving the spindle unit relatively to the work. A feeding controller for controlling a feeding operation of the feeder controls the speed of rotation of the servo motor on the basis of feed speed data stored in a memory. The feed speed data comprises a first feed speed corresponding to the time when the cutting tool cuts through an end surface of the work crossing the direction of feeding and a second feed speed corresponding to the time of normal working and higher than the first feed speed.

Abstract: An edge grinder includes a shaft for supporting a glass sheet template in spaced relationship to one another. The template and glass sheet are rotated about a sheet axis of rotation and a grinding wheel is rotated about a wheel axis of rotation. The grinding wheel and a template follower spaced from the grinding wheel are biased against the glass sheet and template respectively, to shape the glass sheet to a desired contour as defined by the template. As the grinding wheel engages varying edge damage and/or increased peripheral rotational speed of the sheet, the load on the motor powering the grinding wheel varies as indicated by current input to the grinding wheel motor. Variations in the current input are responded to by selectively varying the rotational speed of the sheet. In this manner, a uniform rate of material removal is maintained to eliminate overheating of the glass edge and grinding wheel during shaping of the glass sheet.