Home / Standards / GB 9074.21-88 GB 9074.21-88 Cross-recessed hexagon head tapping screws with indentation and large plain washers — Assemblies 十字槽凹穴六角头自攻螺钉和大平垫圈组合件 Standard Type GB ICS N/A CCS N/A Status N/A Issue Date N/A Implementation N/A Responsible Dept N/A Drafting Unit N/A