Online Parts Store › Phillips Machine Screw - Flat Head, 3/8"-16 x 4" Image 1 of 1 Phillips Machine Screw - Flat Head, 3/8"-16 x 4" $47.17 18-8 Stainless Steel. Add To Cart Added! 18-8 Stainless Steel. You Might Also Like Flat Washer, 3/8", .062" Thick, OD 1" $40.34 Phillips Tapping Screws - Flat Head, #14 x 3/4" $44.09 Stainless Fender Washer 5/8", .109" Thick, OD 2" $37.03 Phillips Tapping Screws - Flat Head, #14 x 1-3/4" $36.21 Nylon Insert Locknut - Stainless 5/8-11 $35.08