ISO 2541:2016规定了带半径中心孔的中心钻的尺寸？R型。 它只涵盖公制尺寸，被认为是未来此类钻机的唯一推荐尺寸。 凹槽可以是直的或螺旋的，由制造商选择。 除非另有说明，这些钻头都是右手切削。 附录A给出了R型中心孔的建议尺寸，可通过合理使用本国际标准中列出的中心钻获得。

ISO 2541:2016 specifies the dimensions of centre drills for centre holes with radius?Type R. It covers only metric dimensions, regarded as the only recommended dimensions in the future for this type of drills. The flutes can be straight or spiral at the option of manufacturer. Unless otherwise stated, these drills are right-hand cutting. Annex A gives the recommended dimensions for the centre holes, Type R, which can be obtained by a rational use of the centre drills listed in this International Standard.