Online Parts Store › Phillips Machine Screw - Pan Head. 5/16"-18 x 4" Image 1 of 1 Phillips Machine Screw - Pan Head. 5/16"-18 x 4" $36.28 18-8 Stainless Steel. Add To Cart Added! 18-8 Stainless Steel. You Might Also Like Stainless Cotter Pin 1/16" x 1/2" $9.76 Stainless Fender Washer 1/4", .062" Thick1/4", OD1-1/4" $59.33 Seachoice 18-8 Stainless Steel Wing Nuts, 1/4-20 Size, Pack of 100 $110.41 Seachoice 01007 Lock Washer, #10 $10.77 Stainless Cotter Pin 3/32" x 1-1/4" $54.48