... Machine threads.Head typesHexagon head,Mushroom head,Pan head,Countersunk head,Bugle head,Oval head,Hex flange head,Round head,Ball head,Button head...Socket typesPhillip ... 20 years experiences in screw,bolt,nut,washer,rivet, stud, pin,wrench and so on .2 ... % ,is higher hardness than other.2.Fasteners' Head is much thicker ,it is strong not break ... any query ! Torx Socket Pan Head Self Tapping Screw