1 3/8-12 x 6 1/2 Socket Cap Screw Alloy

6-lobe drive prevents driver bit cam-out and stripping in recess

Nuts are made from a low-carbon steel which conforms to the following chemical composition requirements: Carbon-0

1/2-13 x 8 1/2 Socket Cap Screw Alloy

Socket Cap Screws in 18-8 (A2) Stainless Steel by Brighton Best

4-40 x 5/16 Phillips Flat 82 Undercut Machine Screw Black Zinc Plated (10,000) Nylon Insert Locknuts Zinc Plated 1 3/8-12 x 6 1/24 40 x 5 16 Phillips Flat 82 Undercut Machine Screw Black Zinc Plated (10,000) . Black Zinc is an acidic, low temperature powdered product developed to impart a black conversion coating of zinc die casting, galvanized stock and electroplated zinc parts. The black coating serves as a base for organic coatings (lacquers, paints, waxes and oils) and also provides an esthetic appeal.