Copper MACHINE SCREW 1.ISO,ANSI,JIS,DIN,BS& non- ... 4.8 ,6.8,8.8,9.8... ..... Copper MACHINE SCREW, brass shoulder bolt screw ,BRASS ALLEN SCREW. A ... drywall screw;Type "M","UNC","UNF","BSW"threads for Machine threads.Head typesHexagon head,Mushroom head,Pan head,Countersunk ... are used in most of places such as drywall,concrete,chipboard,machine,wood...2) Main export market:North America,South America ...