This standard specifies the types and dimensions of straight shank long twist drills. This standard applies to straight shank long twist drills with a diameter of 1.00 mm to 31.50 mm.
GB/T 6135.4-1996 history
2008GB/T 6135.3-2008 Parallel shank twist drills.Part3:The types and dimensions for parallel shank long series twist drills
1996GB/T 6135.4-1996 Parallel shank twist drills--Part 4: The types and dimensions for parallel shank long series twist drills
GB/T 6135.4-1996 Parallel shank twist drills--Part 4: The types and dimensions for parallel shank long series twist drills was changed to GB/T 6135.3-2008 Parallel shank twist drills.Part3:The types and dimensions for parallel shank long series twist drills.