Some of the common head types are: Flat, Flat Undercut, Oval, Oval Undercut, Round, Fillister, Pan, Binding, Truss, Hex, Sems, Hex Washer, Socket Cap, Hex Cap, Elevator, Wood, Dowel, Stud, Slotted Set, Threaded Rod, Socket Set. The head of the screws can be: Socket, Hex, Slotted, One Way, Pozidrive, Phillips, Torx, Square. The most common thread types are American National Standard Machine Screws or Metric. Most screws are available in Steel (conduct’s the magnetic field), Brass (non-magnetic), Stainless Steel, Silicon Bronze and Nylon.