目前测量如图1所示工件的φD一般只能用卡尺,但很难测量得准确。我们制作一套量具如图2,解决了这一问题。量具是由百分表、表座和测头三部分组成(见图2),测头的锥顶角做成126°52＇,其原因为:假定测头在位置1处所测直径为D_1,下降h后,在位置2处所测直径为D_2(见图3),则:这就是说,百分表指示值的变化反映被测直 The current measurement shown in Figure 1, the workpiece φD generally only caliper, but difficult to measure accurately. We make a set of measuring tools as shown in Figure 2, to solve this problem. Gauge is composed of dial indicator, watch holder and probe three parts (see Figure 2), the cone angle of the probe made 126 ° 52 ’, the reason is: Assuming the probe measured at position 1 diameter D_1 , After falling h, the measured diameter at position 2 D_2 (see Figure 3), then: This means that the change in indicator indicates the measured straight