Machine Screw Head Type Round Material Steel Finish Zinc Plated Drive Slotted Thread Size 1/4 In.-20 Fastener Length 2 1/2 in Head Width 0.477 in Head Height 0.472 in Tensile Strength 60 000 psi Dimensional Standards ASME B18.6.3 Pack Size Small Minimum Thread Length Not Applicable Type Standard Machine Screw Washer Outside Diameter Not Applicable Washer Thickness Not Applicable Maximum Head Width 0.477 in Minimum Head Width 0.442 in Maximum Head Height 0.472 in