... 8 ,6.8,8.8,9.8.... SMALL MACHINE SCREWS,STAINLESS STEEL SCREW,CHIPBOARD SCREW MACHINE SCREW . A good non-standard fastenerS manufacturer for ... "A","AB", Threads for chipboard screw,wood screw,drywall screw;Type "M","UNC","UNF","BSW"threads for Machine threads.Head typesHexagon head,Mushroom head ... quality 1.The material are always use C1022 ,The percent C element is 0.18%-0.23% ,is higher hardness ...