Abstract: An apparatus for measuring the roundness and waviness of workpiece surfaces comprises a first peak-to-peak detector for detecting the absolute peak-to-peak value of the sum of a signal representative of the roundness error of the workpiece and a signal representative of the eccentric center of the workpiece. A low-pass filter passes only the low frequency eccentricity signal which is applied to a second peak-to-peak detector for detecting the absolute peak-to-peak value thereof. The outputs from both detecting devices are fed to an arithmetic means for effecting subtraction of the absolute value of the output signal from the second peak-to-peak detector from that of the first peak-to-peak detector thereby obtaining a signal representative of the peak or maximum amount of waviness of the workpiece surface at or near the point of maximum eccentricity error and unaffected by any eccentricity error.

Abstract: In a grinding machine, either the revolutional speed of the workpiece or of the grinding wheel is controlled and further the infeed speed of the wheel to the workpiece is controlled so that the optimum grinding condition, having a suitable ratio of the workpiece surface speed to the grinding wheel surface speed and a suitable ratio of the infeed speed to the workpiece revolutional speed, is obtained. The former ratio is maintained despite the wheel diameter decrease caused by wheel dressings.

Abstract: Grinding method and apparatus in which metal removal rate of workpieces is controlled to predetermined values at least during fine grinding. The metal removal is measured out by an in-process size detector, which measures the workpiece diameter under grinding, and is compared with one of the predetermined values directly or indirectly after being converted into metal removal-to-time rate. The deviation of metal removal from the predetermined value effects to control the infeed movement of an infeed table which displaces the grinding wheel to infeed relative to the workpiece.