图1刊登的螺旋测微计(千分尺)是一种具有多种测量用途的精密量具。对常用的各种千分尺难以测量的工件,如管壁、圆桶壁的厚度,内孔到外壁的距离,槽子与端面间的尺寸,以及圆头螺钉半球形钉头的高度等,都能够准确和迅速地测量出来(见图2)。这种千分尺的构造与普通外径千分尺稍有不同。螺旋及刻度部分是与外径千分尺一样的。外径千分尺尺身的一端有一小段固定测砧,以 The micrometer (Micrometer), published in Figure 1, is a precision gauge with a wide range of measurement applications. Workpieces that are difficult to measure, such as tube wall, drum wall thickness, distance from the hole to the outer wall, the size of the groove between the end face and the height of the dome-shaped hemispherical nail head, can be accurately And quickly measured (see Figure 2). The construction of the micrometer is slightly different from the ordinary micrometer. Spiral and scale part is the same as the outer diameter micrometer. Outer diameter micrometer foot end of a small fixed measuring anvil