GB/T 6138.1-1997 攻丝前钻孔用阶梯麻花钻第1部分:直柄阶梯麻花钻的型式和尺寸

标准编号：GB/T 6138.1-1997

标准名称：攻丝前钻孔用阶梯麻花钻第1部分:直柄阶梯麻花钻的型式和尺寸

英文名称：Subland twist drills for holes prior to tapping screw threads--Part 1:The types and dimensions for subland twist drills with parallel shanks