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 Flat Washer, 1/2", .078" Thick, OD 1-3/8" $74.51 Nylon Insert Locknut - Stainless 5/8-11 $35.08 Phillips Tapping Screw - Pan Head, #8 x 1-1/4" $27.71 Phillips Tapping Screws - Flat Head, #8 x 1-1/4" $19.34 Seachoice 01008 Lock Washer, #12 $16.44