GB/T 20330-2006
攻丝前钻孔用麻花钻直径
Drill diameter for use prior to tapping screw threads
2006-07-20
GB/T 6138-2023
攻丝前钻孔用阶梯麻花钻
Subland twist drills for holes prior to tapping screw threads
2023-09-07
DIN 8378
Subland twist drills with parallel shank for holes prior to tapping screw threads
攻丝螺纹前用于钻孔的直柄小带麻花钻
2006-11-01
DIN 8379
Subland twist drills with Morse taper shanks for holes prior to tapping screw threads
攻丝螺纹前孔用莫氏锥柄小带麻花钻
2006-11-01