THE HYDROGEN SULPHIDE (H2S) PAPER-STRIP TEST

Disclosed is a blade cover in a cutting apparatus comprising a chuck table for holding a workpiece to be cut and cutting means for cutting the workpiece, which comprises a spindle having a rotary blade detachably attached thereto and a spindle housing for rotatably holding the spindle. The blade cover is fixed to the spindle housing on its front side, and it comprises: a rear nozzle assembly for flushing water to the rotary blade on its rear side; a front nozzle assembly for flushing water to the rotary blade on its front side; and blade detecting means for detecting the condition of the rotary blade. The front nozzle assembly is adapted to be put selectively in operative or inoperative position, and the blade detecting means is adapted to be put selectively in operative or inoperative position in unison with the front nozzle assembly. With this arrangement the rotary blade can be changed readily.