Thread Diameter 0.3125" Head Diameter 0.597" Head Height 0.290" Phillips Drive Size #4 18-8 Stainless Steel provides strength and offers good corrosion resistance in many environments. Oval heads have a low dome and are tapered for counterinking. Machine Screws are a straight shanked fastener designed to be used in a hole that is pre tapped or a clear hole with a nut on the opposite side. Stainless Steel Machine Screws are used in applications which require general atmospheric corrosion resistance, refridgeration quipment, and food processing machinery. These screws have an approximate Rockwell hardness of B85 - B95 and a minimum Tensile Strength of 80,000 PSI