McMaster-Carr logo
    Filter by
    System of Measurement
    Thread Size
    Industrial Info Compare
    Thread Direction
    Industrial Info Compare
    Thread Type
    Thread Spacing
    Industrial Info Snippet
    Specifications Met
    Fastener Strength Rating
    Military Specification
    DFARS Specialty Metals
    Industrial Info Compare
    Export Control Classification Number (ECCN)
    Drive Style
    Industrial Info Snippet
    Coupling Nut Profile
    Industrial Info Compare
    Forward
    Enter e-mail addresses in the fields below
    Message
    Cancel
    Print
    How can we improve?
    Comments
    E-mail address (if you would like a response)
    34 Products

    Hex Nuts

    The most commonly used hex nuts, these are suitable for fastening most machinery and equipment.
    Medium-Strength Steel
    Image of Product. Front orientation. Hex Nuts. Hex Nuts.
    These Grade 5 or Class 8 nuts are your go-to for fastening most machinery and equipment. To avoid stripped threads during installation, make sure your screw has a comparable strength rating.
    Zinc-Plated Steel—A step up from plain steel, the zinc plating withstands occasional exposure to moisture.
    Steel—Best for dry environments since moisture will cause these nuts to rust.
    Thread
    Size
    Wd.
    Ht.
    Fastener Strength
    Grade/Class
    Specs. Met
    Pkg.
    Qty.
    Pkg.
    Zinc-Plated Steel
    2"-4 1/2
    		3"1 23/32"SAE Grade 5
    		ASME B18.2.21000000000000000
     
    Steel
    2"-4 1/2
    		3"1 23/32"SAE Grade 5
    		ASME B18.2.2100000000000000
     
    High-Strength Steel
    Image of Product. Front orientation. Hex Nuts. Hex Nuts.
    Rated Grade 8, Grade C, or Class 10, these nuts are about 25% stronger than medium-strength steel nuts. They are commonly used to fasten components in valves, pumps, motors, and other high-stress applications. To avoid stripped threads during installation, make sure your screw has a comparable strength rating.
    Zinc-Yellow-Chromate-Plated Steel—With a more durable finish than clear zinc plating, these nuts are suitable for most wet and outdoor environments. However, they won't hold up to the harsh chemicals that stainless steel can.
    Black-Oxide Steel—Typically chosen for their appearance, these nuts have a dark, matte coating to create a finished look. They offer minimal corrosion resistance, so they're best for dry environments.
    Zinc-Flake-Coated Steel—The most durable zinc coating, zinc flake is a multilayer finish that resists wear for long-term rust protection. Similar to zinc yellow-chromate, it won't hold up to harsh chemicals like stainless steel can.
    Steel—Best for dry environments since moisture will cause these nuts to rust.
    Thread
    Size
    Wd.
    Ht.
    Fastener Strength
    Grade/Class
    Pkg.
    Qty.
    Pkg.
    Zinc-Yellow-Chromate-Plated Steel
    2"-4 1/2
    		3"1 23/32"SAE Grade 8
    		1000000000000000
     
    Black-Oxide Steel
    2"-4 1/2
    		3"1 23/32"SAE Grade 8
    		100000000000000
     
    Zinc-Flake-Coated Steel
    2"-4 1/2
    		3"1 23/32"SAE Grade 8
    		100000000000000
     
    Steel
    2"-4 1/2
    		3"1 23/32"SAE Grade 8
    		100000000000000
     
    Corrosion-Resistant Stainless Steel
    Image of Product. Front orientation. Hex Nuts. Hex Nuts.
    18-8 Stainless Steel—The choice for wet and outdoor environments, these nuts resist rust. However, they won't hold up to the harsh chemicals that 316 stainless steel can.
    Super-Corrosion-Resistant 316 Stainless Steel—Superior to 18-8 stainless steel, these nuts won't degrade when exposed to harsh weather, salt water, and most chemicals.
    Thread
    Size
    Wd.
    Ht.
    Pkg.
    Qty.
    Pkg.
    18-8 Stainless Steel
    2"-4 1/2
    		3"1 23/32"1000000000000000
     
    Super-Corrosion-Resistant 316 Stainless Steel
    2"-4 1/2
    		3"1 23/32"100000000000000
     
    Corrosion-Resistant Stainless Steel with Material Certificate
    Image of Product. Front orientation. Hex Nuts. Hex Nuts.
    Black-Oxide 18-8 Stainless Steel—Typically chosen for their appearance, these nuts have a dark, matte coating to create a finished look. They resist rust in wet and outdoor environments, but won't hold up to the harsh chemicals that 316 stainless steel can.
    Super-Corrosion-Resistant Black-Oxide 316 Stainless Steel—Combines a finished appearance with the rust resistance of 316 stainless steel. Even if the coating wears off, these nuts will hold up in just about any environment, including salt water and most chemicals.
    Certificates with a traceable lot number are available for these products. Download certificates from ORDER HISTORY after your order ships.
    Thread
    Size
    Wd.
    Ht.
    Pkg.
    Qty.
    Pkg.
    Black-Oxide 18-8 Stainless Steel
    2"-4 1/2
    		3"1 23/32"1000000000000000
     
    Super-Corrosion-Resistant Black-Oxide 316 Stainless Steel
    2"-4 1/2
    		3"1 23/32"100000000000000
     

    Mil. Spec. Hex Nuts

    These nuts are manufactured and tested to strict U.S. military standards for material and construction.
    Low-Strength Steel
    Image of Product. Front orientation. Hex Nuts. Mil. Spec. Hex Nuts.
    Rated Grade 2, Class 6, or lower, these nuts are about half as strong as medium-strength nuts. They are suitable for light duty fastening applications, such as securing access panels. Use them with screws that have a similar strength rating to avoid stripping threads during installation.
    Steel—Best for dry environments since moisture will cause these nuts to rust.
    Thread
    Size
    Wd.
    Ht.
    Mil. Spec.
    Fastener Strength
    Grade/Class
    Pkg.
    Qty.
    Pkg.
    Steel
    2"-4 1/2
    		3"1 23/32"MIL-DTL-1222SAE Grade 2
    		1000000000000000
     

    Thin-Profile Hex Nuts

    About half the height of standard-profile nuts, these fit in spaces with low clearance. You can also use them as jam nuts by threading them against another hex nut to hold it in place.
    Medium-Strength Steel
    Image of Product. Front orientation. Hex Nuts. Thin-Profile Hex Nuts.
    These Grade 5 or Class 04 nuts are your go-to for fastening most machinery and equipment. To avoid stripped threads during installation, make sure your screw has a comparable strength rating.
    Zinc-Plated Steel—A step up from plain steel, the zinc plating withstands occasional exposure to moisture.
    Thread
    Size
    Wd.
    Ht.
    Fastener Strength
    Grade/Class
    Specs. Met
    Pkg.
    Qty.
    Pkg.
    Zinc-Plated Steel
    2"-4 1/2
    		3"1 3/32"SAE Grade 5
    		ASME B18.2.21000000000000000
     
    High-Strength Steel
    Image of Product. Front orientation. Hex Nuts. Thin-Profile Hex Nuts.
    Rated Grade 8, Grade C, or Class 10, these nuts are about 25% stronger than medium-strength steel nuts. They are commonly used to fasten components in valves, pumps, motors, and other high-stress applications. To avoid stripped threads during installation, make sure your screw has a comparable strength rating.
    Zinc-Yellow-Chromate-Plated Steel—With a more durable finish than clear zinc plating, these nuts are suitable for most wet and outdoor environments. However, they won't hold up to the harsh chemicals that stainless steel can.
    Steel—Best for dry environments since moisture will cause these nuts to rust.
    Thread
    Size
    Wd.
    Ht.
    Fastener Strength
    Grade/Class
    Specs. Met
    Pkg.
    Qty.
    Pkg.
    Zinc-Yellow-Chromate-Plated Steel
    2"-4 1/2
    		3"1 3/32"SAE Grade 8
    		ASME B18.2.21000000000000000
     
    Steel
    2"-4 1/2
    		3"1 3/32"SAE Grade 8
    		ASME B18.2.2100000000000000
     
    Low-Strength Steel
    Image of Product. Front orientation. Hex Nuts. Thin-Profile Hex Nuts.
    Rated Grade 2, Class 6, or lower, these nuts are about half as strong as medium-strength nuts. They are suitable for light duty fastening applications, such as securing access panels. Use them with screws that have a similar strength rating to avoid stripping threads during installation.
    Steel—Best for dry environments since moisture will cause these nuts to rust.
    Thread
    Size
    Wd.
    Ht.
    Fastener Strength
    Grade/Class
    Pkg.
    Qty.
    Pkg.
    Steel
    2"-4 1/2
    		3"1 3/32"SAE Grade 2
    		1000000000000000
     
    Corrosion-Resistant Stainless Steel
    Image of Product. Front orientation. Hex Nuts. Thin-Profile Hex Nuts.
    18-8 Stainless Steel—The choice for wet and outdoor environments, these nuts resist rust. However, they won't hold up to the harsh chemicals that 316 stainless steel can.
    Super-Corrosion-Resistant 316 Stainless Steel—Superior to 18-8 stainless steel, these nuts won't degrade when exposed to harsh weather, salt water, and most chemicals.
    Thread
    Size
    Wd.
    Ht.
    Pkg.
    Qty.
    Pkg.
    18-8 Stainless Steel
    2"-4 1/2
    		3"1 3/32"1000000000000000
     
    Super-Corrosion-Resistant 316 Stainless Steel
    2"-4 1/2
    		3"1 3/32"100000000000000
     

    Left-Hand-Thread Thin-Profile Hex Nuts

    These nuts tighten when turned to the left. Use them with left-hand rods and screws to prevent counterclockwise-moving parts from loosening. About half the height of standard-profile nuts, these fit in spaces with low clearance. You can also use them as jam nuts by threading them against another hex nut to hold it in place.
    Low-Strength Steel
    Image of Product. Front orientation. Contains Annotated, MultipleImages. Hex Nuts. Left-Hand-Thread Thin-Profile Hex Nuts.
    Rated Grade 2, Class 6, or lower, these nuts are about half as strong as medium-strength nuts. They are suitable for light duty fastening applications, such as securing access panels. Use them with screws that have a similar strength rating to avoid stripping threads during installation.
    Black-Oxide Steel—Typically chosen for their appearance, these nuts have a dark, matte coating to create a finished look. They offer minimal corrosion resistance, so they're best for dry environments.
    Thread
    Size
    Wd.
    Ht.
    Fastener Strength
    Grade/Class
    Specs.
    Met
    Pkg.
    Qty.
    Pkg.
    Black-Oxide Steel
    2"-4 1/2
    		3"1 3/32"SAE Grade 2
    		ASTM A1081000000000000000
     
    Corrosion-Resistant Stainless Steel
    Image of Product. Front orientation. Contains Annotated, MultipleImages. Hex Nuts. Left-Hand-Thread Thin-Profile Hex Nuts.
    18-8 Stainless Steel—The choice for wet and outdoor environments, these nuts resist rust. However, they won't hold up to the harsh chemicals that 316 stainless steel can.
    Thread
    Size
    Wd.
    Ht.
    Specs. Met
    Pkg.
    Qty.
    Pkg.
    18-8 Stainless Steel
    2"-4 1/2
    		3"1 3/32"ASME B18.2.21000000000000000
     

    Heavy-Profile Hex Nuts

    About 10% wider and taller than standard-profile hex nuts, these handle heavier loads by distributing them over a larger area.
    Medium-Strength Steel
    Image of Product. Front orientation. Hex Nuts. Heavy-Profile Hex Nuts.
    These Grade 5 or Class 8 nuts are your go-to for fastening most machinery and equipment. To avoid stripped threads during installation, make sure your screw has a comparable strength rating.
    Steel—Best for dry environments since moisture will cause these nuts to rust.
    Thread
    Size
    Wd.
    Ht.
    Fastener Strength
    Grade/Class
    Pkg.
    Qty.
    Pkg.
    Steel
    2"-4 1/2
    		3 1/8"1 31/32"SAE Grade 5
    		1000000000000000
     
    Extreme-Strength Steel
    Image of Product. Front orientation. Hex Nuts. Heavy-Profile Hex Nuts.
    These nuts are about 20% stronger than high-strength steel nuts. To avoid stripped threads during installation, make sure your screw has a comparable strength rating.
    Hot-Dipped Galvanized Steel—Combines the strength of steel with the rust resistance of stainless steel. These nuts are an economical alternative to 18-8 stainless steel in wet and outdoor environments, but they won't hold up to salt water and chemicals. The galvanized finish is thicker than other types of coatings, so the threads may be more likely to stick during installation. Use with other hot-dipped galvanized fasteners.
    Steel—Best for dry environments since moisture will cause these nuts to rust.
    Thread
    Size
    Wd.
    Ht.
    Fastener Strength
    Grade/Class
    Specs.
    Met
    Pkg.
    Qty.
    Pkg.
    Hot-Dipped Galvanized Steel
    2"-4 1/2
    		3 1/8"1 31/32"ASTM Grade 2H
    		ASTM A194
    		1000000000000000
     
    Steel
    2"-4 1/2
    		3 1/8"1 31/32"ASTM Grade 2H
    		ASTM A194
    		100000000000000
     
    Low-Strength Steel
    Image of Product. Front orientation. Hex Nuts. Heavy-Profile Hex Nuts.
    Rated Grade 2, Class 6, or lower, these nuts are about half as strong as medium-strength nuts. They are suitable for light duty fastening applications, such as securing access panels. Use them with screws that have a similar strength rating to avoid stripping threads during installation.
    Zinc-Plated Steel—A step up from plain steel, the zinc plating withstands occasional exposure to moisture.
    Steel—Best for dry environments since moisture will cause these nuts to rust.
    Thread
    Size
    Wd.
    Ht.
    Specs. Met
    Pkg.
    Qty.
    Pkg.
    Zinc-Plated Steel
    2"-4 1/2
    		3 1/8"1 31/32"ASME B18.2.21000000000000000
     
    Steel
    2"-4 1/2
    		3 1/8"1 31/32"ASME B18.2.2100000000000000
     
    Corrosion-Resistant Stainless Steel
    Image of Product. Front orientation. Hex Nuts. Heavy-Profile Hex Nuts.
    18-8 Stainless Steel—The choice for wet and outdoor environments, these nuts resist rust. However, they won't hold up to the harsh chemicals that 316 stainless steel can.
    Super-Corrosion-Resistant 316 Stainless Steel—Superior to 18-8 stainless steel, these nuts won't degrade when exposed to harsh weather, salt water, and most chemicals.
    Thread
    Size
    Wd.
    Ht.
    Pkg.
    Qty.
    Pkg.
    18-8 Stainless Steel
    2"-4 1/2
    		3 1/8"1 31/32"1000000000000000
     
    Super-Corrosion-Resistant 316 Stainless Steel
    2"-4 1/2
    		3 1/8"1 31/32"100000000000000
     

    Thin-Heavy-Profile Hex Nuts

    About half the height of standard-profile hex nuts and 10% wider, these fit in spaces with low clearance and handle heavier loads by distributing them over a larger area. You can also use them as jam nuts by threading them against another hex nut to hold it in place.
    Extreme-Strength Steel
    Image of Product. Front orientation. Hex Nuts. Thin-Heavy-Profile Hex Nuts.
    These nuts are about 20% stronger than high-strength steel nuts. To avoid stripped threads during installation, make sure your screw has a comparable strength rating.
    Steel—Best for dry environments since moisture will cause these nuts to rust.
    Thread
    Size
    Wd.
    Ht.
    Fastener Strength
    Grade/Class
    Specs. Met
    Pkg.
    Qty.
    Pkg.
    Steel
    2"-4 1/2
    		3 1/8"1 3/32"ASTM Grade 2H
    		ASME B18.2.2, ASTM A1941000000000000000
     
    Low-Strength Steel
    Image of Product. Front orientation. Hex Nuts. Thin-Heavy-Profile Hex Nuts.
    Rated Grade 2, Class 6, or lower, these nuts are about half as strong as medium-strength nuts. They are suitable for light duty fastening applications, such as securing access panels. Use them with screws that have a similar strength rating to avoid stripping threads during installation.
    Steel—Best for dry environments since moisture will cause these nuts to rust.
    Thread
    Size
    Wd.
    Ht.
    Fastener Strength
    Grade/Class
    Pkg.
    Qty.
    Pkg.
    Steel
    2"-4 1/2
    		3 1/8"1 3/32"SAE Grade 2
    		1000000000000000
     

    Nylon-Insert Locknuts

    Versatile yet economical, these are the most commonly used locknuts. The nylon insert grips the screw to prevent loosening from moderate vibration without damaging threads. However, the insert may become brittle if exposed to high temperatures. These locknuts are reusable a handful of times, but the holding power decreases with each use.
    High-Strength Steel
    Image of Product. Front orientation. Locknuts. Nylon-Insert Locknuts.
    Rated Grade 8, Grade C, or Class 10, these locknuts are about 25% stronger than medium-strength steel nuts. To avoid stripped threads during installation, make sure your screw has a comparable strength rating.
    Zinc-Yellow-Chromate-Plated Steel—With a more durable finish than clear zinc plating, these nuts are suitable for most wet and outdoor environments. However, they won't hold up to the harsh chemicals that stainless steel can.
    Thread
    Size
    Wd.
    Ht.
    Fastener Strength
    Grade/Class
    Insert Max.
    Temp., ° F
    Pkg.
    Qty.
    Pkg.
    Zinc-Yellow-Chromate-Plated Steel
    2"-4 1/2
    		3 9/64"2 13/32"SAE Grade 8
    		2201000000000000000
     

    Locknuts for use with Cotter Pins

    Use these locknuts to secure rotating parts subjected to mild vibration, such as the wheels on carts and hand trucks. They’re not recommended for use on parts exposed to high vibration because the pin can shear under prolonged stress. These nuts are reusable, but you'll need a new cotter pin (not included) with each use.
    Low-Strength Steel
    Image of ProductInUse. Front orientation. Locknuts. Locknuts for use with Cotter Pins.
    Image of Product. Front orientation. Locknuts. Locknuts for use with Cotter Pins.
    Rated Grade 2, Class 6, or lower, these locknuts are about half as strong as medium-strength steel nuts. Use them with screws that have a similar strength rating to avoid stripping threads during installation.
    Zinc-Plated Steel—A step up from plain steel, the zinc plating withstands occasional exposure to moisture.
    Thread
    Size
    Wd.
    Ht.
    For Cotter
    Pin Dia.
    Pkg.
    Qty.
    Pkg.
    Zinc-Plated Steel
    2"-4 1/2
    		3"1 23/32"3/8"1000000000000000
     

    Coupling Nuts

    Also known as extension nuts, these are commonly used to connect lengths of threaded rod and join threaded parts.
    Low-Strength Steel
    Image of Product. Front orientation. Coupling Nuts. Coupling Nuts.
    Rated Grade 2 or lower, these are about half as strong as medium-strength steel coupling nuts. Use them with threaded rods that have a comparable strength rating to avoid stripping threads during installation.
    Zinc-Plated Steel—A step up from plain steel, the zinc plating withstands occasional exposure to moisture.
    Steel—Best for dry environments since moisture will cause these nuts to rust.
    Each
    Thread
    Size
    Lg.
    Wd.
    Threading
    Min. Thread
    Lg.
    1-9
    10-Up
    Zinc-Plated Steel
    2"-4 1/2
    		4 1/2"2 3/4"Fully Threaded—000000000000000000000
     
    Steel
    2"-4 1/2
    		9"3 1/4"Partially Threaded4 3/8"000000000000000000000
     
    Corrosion-Resistant Stainless Steel
    Image of Product. Front orientation. Coupling Nuts. Coupling Nuts.
    18-8 Stainless Steel—The choice for wet and outdoor environments, these nuts resist rust. However, they won't hold up to the harsh chemicals that 316 stainless steel can.
    Each
    Thread
    Size
    Lg.
    Wd.
    Threading
    1-9
    10-Up
    18-8 Stainless Steel
    2"-4 1/2
    		6"3 1/8"Fully Threaded00000000000000000000000
     

    Eye Nuts—For Lifting

    Image of Product. Front orientation. Eye Nuts. Eye Nuts—For Lifting, Style B.

    Style B

    Create your own lifting eye by adding an eye nut to a stud or bolt.
    Note: Capacity applies to the eye nut only. The stud or bolt you use will affect the overall capacity. Eye nuts are for vertical lifting only.
    Warning: Never use to lift people or items over people.
    Fully Threaded
    Image of Product. Front orientation. Eye Nuts. Eye Nuts—For Lifting, Style B.

    Style B

    Galvanized Steel—Galvanized steel eye nuts have a hot-dipped finish for more corrosion resistance than zinc-plated steel.
    Style
    Thread
    Size
    Overall
    Lg.
    Eye
    Dia.
    Vert. Cap.,
    lb.
    Each
    Galvanized Steel
     
    Closed Eye Nuts
    B2"-4 1/2
    		9 15/16"4 1/8"40,00000000000000000
     
    back to top