GB/T 13806.1-1992
Cross recessed raised countersunk head screws for precision -Table3
GB/T 820-1985
Cross recessed raised countersunk head screws-type H
GB/T 820-1985
Cross recessed raised countersunk head screws-type Z
GB/T 820-2000
Cross recessed raised countersunk head screws-type H
GB/T 820-2000
Cross recessed raised countersunk head screws-type Z
GB/T 820-2015
Cross recessed raised countersunk head screws-type H
GB/T 820-2015
Cross recessed raised countersunk head screws-type Z
GB 974-1976
120°Countersunk raised head screws with type H cross recess