Nuts Back Two-Piece Hex Cap Nuts Low Crown Steel, Nickel Finish Castle Nuts Steel, Zinc Plated Hex Coupling Nuts Steel, Zinc Plated Low Carbon Finished Hex Nuts Double Chamfered Steel, Zinc Plated Grade 5 Finished Hex Nuts Steel, Zinc Plated Size Size Size Size Size 6-32 8-32 10-24 10-32 1/4-20 5/16-18 3/8-16 1/2-13 5/8-11 5/8-18 3/4-16 7/8-14 1-14 Nominal Size  A.F. X Length 1/4-20  3/8 X 7/8 5/16-18  1/2 X 1-1/8 3/8-16  9/16 X 1-3/4 1/2-13  11/16 X 1-3/4 5/8-11  13/16 X 2-1/8 3/4-10  1 X 2-1/4 1-8  1 3/8 X 2-3/4 1/4-20 1/4-28 5/16-18 5/16-24 3/8-16 3/8-24 7/16-14 7/16-20 1/2-13 1/2-20 9/16-12 9/16-18 5/8-11 5/8-18 3/4-10 3/4-16 7/8-9 7/8-14 1-8 1-14 1-1/8-7 1-1/8-12 1-1/4-7 1-1/4-12 1-3/8-6 1-3/8-12 1-1/2-6 1-1/2-12 1-5/8-5 1-3/4-5 1-3/4-12 2-4.5 2-12 2-1/4-4.5 2-1/4-12 2-1/2-4 2-1/2-12 2-3/4-4 2-3/4-12 3-4 3-12 All sizes up to and including 1" diameter are domestic. 1/4-20 1/4-28 5/16-18 5/16-24 3/8-16 3/8-24 7/16-14 7/16-20 112-13 1/2-20 9/16-12 9/16-18 5/8-11 5/8-18 3/4-10 3/4-16 7/8-9 7/8-14 1-8 1-14 1-1/8-7 1-1/8-12 1-1/4-7 1-1/4-12 1-1/2-6 1-1/2-12