Phillips, Truss, Thread Rolling Screws. Thread Rolling Taptite thread for drilled, punched or cored holes in all ductile metals and punch extruded metals. Eliminates chips, requires low drive torque and is resistant to vibrational loosening. Truss head screws are weaker than pan or round heads but preferred in applications where minimal clearance exists above the head. Modified truss heads offer low clearance and an extra large bearing surface. Commonly used to attach metal lathe to metal studs.