Online Parts Store › Phillips Machine Screw - Flat Head, 5/16"-18 x 2-1/2" Image 1 of 1 Phillips Machine Screw - Flat Head, 5/16"-18 x 2-1/2" $16.00 18-8 Stainless Steel. Add To Cart Added! 18-8 Stainless Steel. You Might Also Like Phillips Tapping Screw - Truss Head #10 x 1-1/4" $50.76 Phillips Tapping Screws - Oval Head, #12 x 1-1/4" $22.30 Stainless Cotter Pin 5/32" x 1-1/4" $33.25 Phillips Tapping Screw - Pan Head, #8 x 5/8" $18.01 Flat Washer, 3/4", .109" Thick, OD 1-7/8" $47.99