Home / Standards / GB/T 1438.4-2008 GB/T 1438.4-2008 Active Taper shank twist drills - Part 4: The types and dimensions extra-long for Morse taper shank twist drills 锥柄麻花钻 第4部分：莫氏锥柄超长麻花钻的型式和尺寸 Standard Type GBT ICS 25.100.30 CCS J41 Status 现行 Issue Date 2008-11-04 Implementation 2009-04-01 Responsible Dept 中国机械工业联合会 Drafting Unit 中国机械工业联合会