直柄回转刀具 柄直径和传动方头的尺寸

[中文适用范围]： 适用于铰刀、丝锥等。 有两个系列的尺寸。 完整的直径范围分为一定数量的直径级。 在公制表中，正方形的对边尺寸和优选直径按照R20系列优选数字进行缩放。 在英制表中，这些值是相应公制值的精确转换。 [外文原描述]： Applies to reamers, screwing taps, etc. It comprise two series of dimensions. The complete range of diameters is divided into a certain number of diameter steps. In the metric tables, the values of the across flats of the squares and the preferred diameters are scaled in accordance with the R20 series of preferred numbers. In the inch tables, these values are exact conversions of the corresponding metric values.