The GR-7500 is used to sharpen the needles of a nozzle and other rotating bodies. The machine is controlled by PWM regulators. The rotation speed of the spindle and the honed body is displayed. The maximum spindle rotation speed is 7500 rpm. The maximum rotation speed of the sharpened body is 1200 rpm. A grinding wheel is a fine-grained electrocorundum. The grinding machine is used with the DL-UNI20025 kit, which includes: an electronic industrial microscope, a holder, a backlight and a monitor.