Online Parts Store › Nylon Insert Locknut - Stainless 4-40 Image 1 of 1 Nylon Insert Locknut - Stainless 4-40 $21.16 18-8 Stainless Steel. Add To Cart Added! 18-8 Stainless Steel. You Might Also Like Phillips Tapping Screws - Flat Head, #14 x 3" $59.58 Flat Washer, 3/8", .062" Thick, OD 1" $40.34 Phillips Tapping Screws - Flat Head, #14 x 2-1/2" $57.69 Phillips Tapping Screws - Oval Head, #10 x 5/8" $28.59 Square Tapping Screw - Oval Head #10 x 1-1/2" $35.29