Abstract: A seal edge grinding method for a glass funnel, wherein a glass funnel seal edge and a grinding wheel are pressed against each other, and the seal edge is ground with the grinding wheel, comprising: moving a glass funnel and a grinding wheel by a certain quantity in an relatively approaching direction by a mobile unit under numerical control to grind a seal edge of the glass funnel with the grinding wheel by the use of feed controlled grinding; and relatively pressing the seal edge and the grinding wheel at a certain pressure by a pressing force of a pressing unit to grind the seal edge with the grinding wheel by the use of pressure controlled grinding after completion of the feed controlled grinding.

Abstract: A method of electropolishing and grinding the both surfaces of a circular workpiece comprises polishing and grinding the both surfaces of a circular workpiece with a pair of grindingstones which are so arranged as to oppose the polishing/grinding surfaces, the body material of the polishing/grinding surface of the grindingstones being composed of an electric conductive material wherein the grindingstones are connected to the positive pole of a power source and an electrode located in the vicinity of the grindingstones is connected to the negative pole, and a voltage is applied across the positive and negative poles, whereby a dressing operation to the polishing/grinding surfaces is conducted by the electrolysis of the pair of grindingstones during the polishing and grinding operation.