Online Parts Store › Phillips Machine Screw - Oval Head, 5/16"-18 x 4" Image 1 of 1 Phillips Machine Screw - Oval Head, 5/16"-18 x 4" $34.64 18-8 Stainless Steel. Add To Cart Added! 18-8 Stainless Steel. You Might Also Like Phillips Tapping Screw - Pan Head, #12 x 1-1/4" $23.49 Square Tapping Screw - Oval Head #8 x 1-1/2" $54.12 Flat Washer, 5/16", .062" Thick, OD 7/8" $52.44 Nylon Flat Washer #6, 0.32" Thick, OD 3/8" $17.45 Phillips Tapping Screws - Oval Head, #12 x 3/4" $33.07