标准摘要
[中文适用范围]： 本国际标准规定了无保护倒角的中心孔用中心钻（A型）的尺寸。它仅涵盖公制尺寸，未来将被视为此类钻头的唯一推荐尺寸。螺旋 flute 可以由制造商自行决定。除非另有说明，否则这些钻头将是右旋切削的。 [外文原描述]： ISO 866:2016 specifies the dimensions of centre drills for centre holes without protecting chamfers (Type A). It covers only metric dimensions, which are regarded as the only recommended dimensions in the future for this type of drill. The flutes may be straight or spiral, depending on the manufacturer's discretion. Unless otherwise indicated, these drills will be right-hand cutting. Recommended dimensions for Type A centre holes, which can be obtained by a rational use of the centre drills listed in this International Standard, are given in Annex A.
英文名称Centre drills for centre holes without protecting chamfers — Type A