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    28 Products

    Cap Nut Profile

    Cap Nut Profile

    Performance

    Cap Nuts

    Conceal and protect protruding screw threads while fastening parts together. These nuts help prevent damage to surrounding materials and reduce injuries. Also known as acorn nuts, they have a smooth, rounded head that creates a finished look.
    Stainless Steel
    Image of Product. Front orientation. Cap Nuts. Cap 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.
    Black-Oxide 18-8 Stainless Steel—Typically chosen for their appearance, these nuts have a dark, matte coating. They resist rust in wet and outdoor environments but won't hold up to the harsh chemicals that 316 stainless steel can.
    Highly Corrosion-Resistant 316 Stainless Steel—Our most corrosion-resistant cap nuts, these hold up in just about any environment. They won't degrade from exposure to weather, salt water, and most chemicals.
    Pkg.
    Thread
    Size
    Thread
    Dp.
    Wd.
    Ht.
    Pkg.
    Qty.
    1-9
    10-49
    50-Up
    18-8 Stainless Steel
    5/16"-18
    		9/32"9/16"7/16"599022A108000000000000000
    5/16"-18
    		5/16"1/2"17/32"1091855A540000000000000000
     
    Black-Oxide 18-8 Stainless Steel
    5/16"-18
    		5/16"1/2"17/32"591855A126000000000000
     
    Highly Corrosion-Resistant 316 Stainless Steel
    5/16"-18
    		5/16"1/2"17/32"192994A030000000000000
     
    Low-Strength Steel
    Image of Product. Front orientation. Cap Nuts. Cap Nuts.
    Rated Grade 2, Class 6, or lower, these nuts are about half as strong as medium-strength steel 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.
    Black Corrosion-Resistant-Coated Steel—Combines a finished appearance with the rust resistance of stainless steel. The coating has been tested to extreme standards, including 1,000 hours of salt spray resistance, to hold up in wet and outdoor environments. Also known as black luster.
    Nickel-Plated Steel—This plating resists salt water and chemicals better than zinc plating and is less likely to wear off. It also has a bright, polished appearance.
    Pkg.
    Thread
    Size
    Thread
    Dp.
    Wd.
    Ht.
    Pkg.
    Qty.
    1-9
    10-49
    50-Up
    Zinc-Plated Steel
    5/16"-18
    		5/16"1/2"17/32"2591875A140000000000000000000
     
    Black Corrosion-Resistant-Coated Steel
    5/16"-18
    		5/16"1/2"17/32"598667A2300000000000000
     
    Nickel-Plated Steel
    5/16"-18
    		5/16"9/16"15/32"5090532A225000000000000000
     
    Medium-Strength Steel
    Image of Product. Front orientation. Cap Nuts. Cap Nuts.
    About twice as strong as low-strength steel, these Grade 5 nuts fasten 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.
    Black Corrosion-Resistant-Coated Steel—Combines a finished appearance with the rust resistance of stainless steel. The coating has been tested to extreme standards, including 1,000 hours of salt spray resistance, to hold up in wet and outdoor environments. Also known as black luster.
    Pkg.
    Thread
    Size
    Thread
    Dp.
    Wd.
    Ht.
    Fastener Strength
    Grade/Class
    Pkg.
    Qty.
    1-9
    10-49
    50-Up
    Zinc-Plated Steel
    5/16"-18
    		5/16"1/2"17/32"SAE Grade 5
    		1098858A1020000000000000000
     
    Black Corrosion-Resistant-Coated Steel
    5/16"-18
    		5/16"1/2"17/32"SAE Grade 5
    		198858A570000000000000
     
    High-Strength Steel
    Image of Product. Front orientation. Cap Nuts. Cap Nuts.
    Rated Grade 8 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-Plated Steel—A step up from plain steel, the zinc plating withstands occasional exposure to moisture.
    Black Corrosion-Resistant-Coated Steel—Combines a finished appearance with the rust resistance of stainless steel. The coating has been tested to extreme standards, including 1,000 hours of salt spray resistance, to hold up in wet and outdoor environments. Also known as black luster.
    Pkg.
    Thread
    Size
    Thread
    Dp.
    Wd.
    Ht.
    Fastener Strength
    Grade/Class
    Pkg.
    Qty.
    1-9
    10-49
    50-Up
    Zinc-Plated Steel
    5/16"-18
    		5/16"1/2"17/32"SAE Grade 8
    		1090100A102000000000000000000
     
    Black Corrosion-Resistant-Coated Steel
    5/16"-18
    		5/16"1/2"17/32"SAE Grade 8
    		190767A112000000000000
     
    Plastic
    Image of Product. Front orientation. Cap Nuts. Cap Nuts.
    Nylon 6/6—Slippery and abrasion resistant, these nuts thread on smoothly and stand up to daily wear and tear. Nylon will swell and weaken when exposed to moisture, so it's best for dry environments.
    Pkg.
    Thread
    Size
    Wd.
    Ht.
    Temp. Range,
    ° F
    Choose a Color
    Pkg.
    Qty.
    1-9
    10-49
    50-Up
    Nylon 6/6
    5/16"-18
    		1/2"17/32"-40 to 185Black, Off-White5094922A335000000000000000000
     
    Lightweight Aluminum
    Image of Product. Front orientation. Cap Nuts. Cap Nuts.
    2011 Aluminum—One-third the weight of steel, these nuts are commonly used in robotics, automation, and other applications that have weight limitations. They're an alternative to stainless steel for rust resistance but are not as strong.
    Pkg.
    Thread
    Size
    Thread
    Dp.
    Wd.
    Ht.
    Pkg.
    Qty.
    1-9
    10-49
    50-Up
    2011 Aluminum
    5/16"-18
    		7/32"9/16"7/16"1091884A227000000000000000
     
    Brass
    Image of Product. Front orientation. Cap Nuts. Cap Nuts.
    Brass—Conductive and nonmagnetic, brass nuts are commonly used to secure electrical equipment, such as circuit board assemblies and mounting brackets, inside enclosures. They're also softer than most metals, so they won't damage other fastening components.
    Nickel-Plated Brass—In addition to creating a polished appearance, the nickel plating offers better corrosion resistance than plain brass to stand up to solvents and mild chemicals.
    Chrome-Plated Brass—The brightest, shiniest finish we offer, this plating has a mirror-like appearance that's often used in decorative applications. It has better corrosion resistance than plain brass to stand up to solvents and mild chemicals.
    Pkg.
    Thread
    Size
    Thread
    Dp.
    Wd.
    Ht.
    Pkg.
    Qty.
    1-9
    10-49
    50-Up
    Brass
    5/16"-18
    		7/32"9/16"7/16"1092716A610000000000000000
     
    Nickel-Plated Brass
    5/16"-18
    		7/32"9/16"7/16"1092718A44100000000000000
     
    Chrome-Plated Brass
    5/16"-18
    		7/32"9/16"7/16"1092720A740000000000000
     

    Sanitary Cap Nuts

    With extremely smooth sides and rounded edges, these nuts are free of crevices where bacteria can grow. Use them to cover and protect exposed threads while fastening parts together. Nuts are certified by EHEDG to meet sanitary design standards. They have a Buna-N seal on the base that keeps liquid, debris, and other contaminants off the threads. The seal is made with metal and chemical additives, so you can find it with a metal detector or X-ray machine if it falls into your line. Also known as acorn nuts, these have a domed head to create a finished look.
    Stainless Steel
    Image of Product. Front orientation. Cap Nuts. Sanitary Cap Nuts.
    Highly Corrosion-Resistant 316 Stainless Steel—Won't corrode from frequent washdowns and can stand up to the harshest cleaners and detergents.
    Thread
    Size
    Thread
    Dp.
    Wd.
    Ht.
    Seal
    Material
    Certification
    Food Industry Std.
    Each
    Highly Corrosion-Resistant 316 Stainless Steel
    5/16"-18
    		9/32"1/2"25/64"Buna-N
    		EHEDG Certified
    		FDA Compliant 21 CFR 177.2600
    		97511A17000000
     

    High-Heavy-Profile Cap Nuts

    Image of Product. Bottom orientation. Cap Nuts. High-Heavy-Profile Cap Nuts.
    20% wider and taller than standard cap nuts, these have high, flat sides so your wrench won't slip off as you tighten. They cover screws to protect the threads and to prevent damage to surrounding materials. Also known as acorn nuts, they have a smooth, rounded head to create a finished look.
    Stainless Steel
    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
    Thread
    Dp.
    Wd.
    Ht.
    Each
    18-8 Stainless Steel
    5/16"-18
    		3/8"5/8"5/8"92040A11000000
     
    Steel
    Black-Oxide Steel—Typically chosen for their appearance, these nuts have a dark, matte coating. They offer minimal corrosion resistance, so they're best for dry environments.
    Thread
    Size
    Thread
    Dp.
    Wd.
    Ht.
    Each
    Black-Oxide Steel
    5/16"-18
    		3/8"5/8"5/8"90790A18500000
     

    Cap Nut Assortments

    Image of Product. Front orientation. Cap Nuts. Cap Nut Assortments.
    Image of Product. Front orientation. ZoomedIn view. Cap Nuts. Cap Nut Assortments.
    With a range of sizes on hand, you can use these assortments to conceal and protect protruding screw threads while fastening a variety of parts. Also known as acorn nuts, they have a smooth, rounded head that creates a finished look.
    Nickel-Plated Steel—This plating resists salt water and chemicals better than zinc plating and is less likely to wear off. It also has a bright, polished appearance.
    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
    No. of
    Pieces
    Container
    Type
    Each
    Nickel-Plated Steel
    6-32, 8-32, 10-32, 1/4"-20, 5/16"-18, 3/8"-16
    		200Plastic Box91987A300000000
     
    18-8 Stainless Steel
    6-32, 8-32, 10-32, 1/4"-20, 5/16"-18, 3/8"-16
    		200Plastic Box91987A800000000
     

    Cap Nuts with Threadlocker

    Image of Product. Front orientation. Contains Annotated, Border. Cap Nuts. Cap Nuts with Threadlocker.
    These nuts not only conceal and protect protruding screw threads, they also resist loosening from mild vibration. They have a nylon patch bonded to their threads that grips screws for a tighter hold than standard cap nuts. They’re reusable a handful of times, but the patch’s holding power decreases with each use. Also known as acorn nuts, they have a smooth, rounded head that creates a finished look.
    Stainless Steel
    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.
    Highly Corrosion-Resistant 316 Stainless Steel—Our most corrosion-resistant cap nuts, these hold up in just about any environment. They won't degrade from exposure to weather, salt water, and most chemicals.
    Thread
    Size
    Thread
    Dp.
    Wd.
    Ht.
    Pkg.
    Qty.
    Pkg.
    18-8 Stainless Steel
    5/16"-18
    		19/64"1/2"17/32"590421A160000000
     
    Highly Corrosion-Resistant 316 Stainless Steel
    5/16"-18
    		5/16"1/2"17/32"193052A1400000
     

    Nylon-Insert Cap Nuts

    Image of Product. Bottom orientation. Cap Nuts. Nylon-Insert Cap Nuts.
    Get the protection of a cap nut with the vibration resistance of a locknut. These nuts not only conceal protruding screw threads, they also have a nylon insert that grips the screw to prevent loosening from moderate vibration. However, the insert may become brittle if exposed to high temperatures. Nuts are reusable a handful of times, but their holding power decreases with each use.
    Low-Strength Steel
    Rated Grade 2, Class 6, or lower, these nuts 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.
    Nylon 6/6 Cap—The nylon cap on these nuts is softer than metal, so it's less likely to scratch surrounding surfaces or parts.
    Thread
    Size
    Thread
    Dp.
    Wd.
    Ht.
    Fastener Strength
    Grade/Class
    Insert Max.
    Temp., ° F
    Pkg.
    Qty.
    Pkg.
    Zinc-Plated Steel with Nylon 6/6 Cap
    5/16"-18
    		1/4"1/2"1/2"SAE Grade 2
    		2501098190A21000000
     

    Open-End Cap Nuts

    Image of Product. Front orientation. Cap Nuts. Open-End Cap Nuts.
    The open top allows threads to stick out slightly, so you don't have to worry about picking the wrong thread depth. These nuts also engage more threads than standard nuts for a tighter hold. The smooth, curved head creates a finished look, while still partially concealing and protecting the sides of the screw from damage.
    Stainless Steel
    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
    Thread
    Dp.
    Wd.
    Ht.
    Each
    18-8 Stainless Steel
    5/16"-18
    		5/16"9/16"5/16"94301A13500000
     

    Distorted-Thread Cap Nuts

    Image of Product. Bottom orientation. Cap Nuts. Distorted-Thread Cap Nuts.
    For a stronger hold than nylon-insert cap nuts, these have irregularly shaped threads that grip the screw to resist loosening. The threads prevent the nut from backing out in high-vibration applications, but they also increase the effort to install and remove. To get these nuts off, you may need special tools, such as an impact wrench or propane torch. They have a smooth, rounded head that conceals and protects protruding screw threads while creating a finished look. Nuts are not reusable.
    Stainless Steel
    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.
    Highly Corrosion-Resistant 316 Stainless Steel—Our most corrosion-resistant cap nuts, these hold up in just about any environment. They won't degrade from exposure to weather, salt water, and most chemicals.
    Thread
    Size
    Thread
    Dp.
    Wd.
    Ht.
    Pkg.
    Qty.
    Pkg.
    18-8 Stainless Steel
    5/16"-18
    		5/16"1/2"17/32"590507A240000000
     
    Highly Corrosion-Resistant 316 Stainless Steel
    5/16"-18
    		5/16"1/2"17/32"190431A1500000
     
    Low-Strength Steel
    Rated Grade 2, Class 6, or lower, these nuts 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
    Thread
    Dp.
    Wd.
    Ht.
    Fastener Strength
    Grade/Class
    Pkg.
    Qty.
    Pkg.
    Zinc-Plated Steel
    5/16"-18
    		23/64"1/2"17/32"SAE Grade 2
    		2590455A170000000
     
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