Online Parts Store › Phillips Machine Screw - Flat Head, 5/16"-18 x 3" Image 1 of 1 Phillips Machine Screw - Flat Head, 5/16"-18 x 3" $18.14 18-8 Stainless Steel. Add To Cart Added! 18-8 Stainless Steel. You Might Also Like Phillips Tapping Screw - Pan Head, #10 x 2-1/2" $37.66 Square Tapping Screw - Oval Head #10 x 1-1/4" $57.05 Phillips Tapping Screw - Pan Head, #10 x 1-1/4" $32.56 Blind Rivet, 1/8" x 1/4" $43.39 Square Tapping Screw - Oval Head #8 x 1-1/2" $54.12