Especially useful in metal-to-metal or where heavy duty fastening is required.00 x 12 mm Phillips Flat Machine Screw, Zinc Plated Steel, 25 PK Commonly used with flat or lockwashers. Machine screws are used in fastening nearly all types of hard materials..
1/2"-13 Socket Head Cap Screw, Plain Steel, 1 in Length, 10 PK A hex key is required to tighten or loosen a socket screw. Socket screws are commonly used in assemblies that do not provide sufficient clearance for a conventional wrench or socket..