附图是一种专门在圆柱形工件的端面上划中心线的 V 形体。在 V 形体上有两个 V 形槽,一个90°,另一个48°50＇。两个 V 形槽的底点距底面的高度相等(如图中虚线所示)。在48°50＇的 V 形槽下面有一个销钉,外边缘恰好通过这个 V 形槽的中心。划线时,先将 V 形体放在平板上,将工件放在90°的 V 形槽内,把划针盘的划针高度,调整到和工件圆柱面的最高点相等,然后把工件放到48°50＇的 V 形槽里。这时,只要向右移动划针盘,就 The figure is a V-shaped body centered on the end face of a cylindrical workpiece. There are two V-shaped grooves on the V-shaped body, one 90 ° and the other 48 ° 50 ’. The bottoms of the two V-shaped grooves are equal in height to the bottom (as shown by the dotted lines in the figure). Below the 48 ° 50 ’V-groove there is a pin whose outer edge just passes through the center of this V-groove. Marking, the first V-shaped body on the flat, the workpiece on the V-groove 90 °, the needle plank needle stroke height, and the highest point of the cylindrical surface of the workpiece equal, and then put the workpiece 48 ° 50 ’V-groove. At this moment, just move the dial to the right