Self-centring chucks for machine tools with two-piece jaws (tongue and groove type) — Sizes for interchangeability and acceptance test specifications
带两件式钳口(舌型和槽型)的机床用自定心卡盘.互换性尺寸和验收试验规范
Defines precision classes as follows: class I, corresponding to precision chucks; class II, corresponding to normal accuracy chucks. This second edition cancels and replaces the first edition (1975).