McMaster-Carr logo
    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)
    17 Products

    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
    6-32
    		5/32"5/16"11/32"1091855A430000000000000000
    6-32
    		3/16"5/16"9/32"1099022A102000000000000
     
    Black-Oxide 18-8 Stainless Steel
    6-32
    		5/32"5/16"11/32"1091855A121000000000000
     
    Highly Corrosion-Resistant 316 Stainless Steel
    6-32
    		5/32"5/16"11/32"592994A00700000000000000
     
    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
    6-32
    		5/32"5/16"11/32"5091875A110000000000000000000
     
    Black Corrosion-Resistant-Coated Steel
    6-32
    		5/32"5/16"11/32"1098667A110000000000000000
     
    Nickel-Plated Steel
    6-32
    		5/32"5/16"1/4"10090532A1000000000000000
     
    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
    6-32
    		19/64"11/32"-40 to 185
    Black
    ,
    Off-White
    		10094922A305000000000000000000
     
    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
    6-32
    		3/16"5/16"19/64"1091884A213000000000000000000
     
    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
    6-32
    		1/8"5/16"9/32"5092716A007000000000000000000
     
    Nickel-Plated Brass
    6-32
    		1/8"5/16"9/32"2592718A381000000000000
     
    Chrome-Plated Brass
    6-32
    		1/8"5/16"9/32"1092720A681000000000000
     

    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
     

    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.
    Thread
    Size
    Thread
    Dp.
    Wd.
    Ht.
    Pkg.
    Qty.
    Pkg.
    18-8 Stainless Steel
    6-32
    		5/32"5/16"11/32"1090507A210000000
     
    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
    6-32
    		5/32"5/16"11/32"SAE Grade 2
    		5090455A110000000
     

    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
    6-32
    		1/4"5/16"1/4"94301A11000000
     
    back to top