久久综合亚洲欧美成人_超碰人人干人人_夜夜爱av_国产成人8x视频一区二区_国产精品亚洲国产三区_操操插插

The machine is designed to grind four straight grooves of equal angle, equal width, equal depth and equal length on the grinding wheel surface. The operating cycle is controlled by automatic program, and all the slotting actions can be completed by pressing one button.