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 Tee Nut - Stainless 5/16"-18 $26.64 Seachoice 01533 Hex Nut, 1/2-13 $66.78 Square Tapping Screw - Flat Head,#8 x 1-1/4" $28.68 Nylon Flat Washer #6, 0.32" Thick, OD 3/8" $17.45 Nylon Insert Locknut - Stainless 3/4-10 $53.60