4(four) jaws self centering Lathe chuck,K12 series. 4 jaws Self-centering chuck. K12 series Four-jaw Self-centering chuck is suitable for batch process of square,eight-square prism accessories and is self centring. Type K12 provides two sets of clutches in different directions.Type K12A provides ISO3442 standard clutches,and Type K12C provides traditional separate clutches. Size: 80mm-500mm.