Home / Standards / GB T 31 GB T 31 Hexagon head bolts with holes in shank — Fine pitch thread [1].3-88 六角头螺杆带孔螺栓细牙 [1].3-88 Standard Type GBT ICS N/A CCS N/A Status N/A Issue Date N/A Implementation N/A Responsible Dept N/A Drafting Unit N/A