Online Parts Store › Phillips Machine Screw - Pan Head. 5/16"-18 x 2-1/2" Image 1 of 1 Phillips Machine Screw - Pan Head. 5/16"-18 x 2-1/2" $21.73 18-8 Stainless Steel. Add To Cart Added! 18-8 Stainless Steel. You Might Also Like Seachoice 18-8 Stainless Steel Wing Nuts, 1/4-20 Size, Pack of 100 $110.41 Stainless Fender Washer 5/16", .078" Thick, OD 1-1/2 $54.04 Seachoice 01006 Lock Washer, #8 $15.43 Phillips Tapping Screw - Truss Head #10 x 1" $33.32 Stainless External Tooth Lock Washer 5/16" $19.48