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)
    29 Products

    Left-Hand-Thread Thin-Profile Hex Nuts
    3D CAD models available

    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.
    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.
    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
    6-32
    		5/16"3/32"100000000000000
     
    Super-Corrosion-Resistant 316 Stainless Steel
    6-32
    		5/16"3/32"10000000000000
     
    Brass
    Image of Product. Front orientation. Contains Annotated, MultipleImages. Hex Nuts. Left-Hand-Thread Thin-Profile Hex 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.
    Thread
    Size
    Wd.
    Ht.
    Each
    Brass
    6-32
    		5/16"3/32"00000000000000
     

    Mil. Spec. Narrow-Profile Hex Nuts
    3D CAD models available

    These nuts are manufactured and tested to strict U.S. military standards for material and construction. They are about 20% narrower to fit in tight spots where standard-profile nuts won't fit. Also known as small-pattern hex nuts.
    Corrosion-Resistant Stainless Steel
    Image of Product. Bottom orientation. Hex Nuts. Mil. Spec. Narrow-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
    6-32
    		1/4"3/32"Fed. Spec. FF-N-836, NAS671C610000000000000000
     

    Thin-Profile Nylon-Insert Locknuts
    3D CAD models available

    About half the height of standard-profile locknuts, these fit in spaces with low clearance. You can also use them as jam nuts by threading them against a hex nut to hold it in place. 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.
    Low-Strength Steel
    Image of Product. Front orientation. Locknuts. Thin-Profile Nylon-Insert Locknuts.
    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.
    Black Zinc-Plated Steel—The dark zinc plating withstands occasional exposure to moisture while creating a finished look.
    Black Corrosion-Resistant-Coated Steel—These nuts combine 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.
    Thread
    Size
    Wd.
    Ht.
    Insert Max.
    Temp., ° F
    Pkg.
    Qty.
    Pkg.
    Zinc-Plated Steel
    6-32
    		5/16"1/8"220100000000000000000
     
    Black Zinc-Plated Steel
    6-32
    		5/16"1/8"220250000000000000
     
    Black Corrosion-Resistant-Coated Steel
    6-32
    		5/16"1/8"22050000000000000
     
    Corrosion-Resistant Stainless Steel
    Image of Product. Front orientation. Locknuts. Thin-Profile Nylon-Insert Locknuts.
    18-8 Stainless Steel—The choice for wet and outdoor environments, these locknuts 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 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.
    Thread
    Size
    Wd.
    Ht.
    Insert Max.
    Temp., ° F
    Pkg.
    Qty.
    Pkg.
    18-8 Stainless Steel
    6-32
    		5/16"1/8"22010000000000000000
     
    Black-Oxide 18-8 Stainless Steel
    6-32
    		5/16"1/8"22010000000000000000
     

    Mil. Spec. Thin-Profile Nylon-Insert Locknuts
    3D CAD models available

    These locknuts are manufactured and tested to strict U.S. military standards for material and construction. They are about half the height of standard-profile locknuts to fit in spaces with low clearance. You can also use them as jam nuts by threading them against a hex nut to hold it in place. 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.
    Low-Strength Steel
    Image of Product. Front orientation. Locknuts. Mil. Spec. Thin-Profile Nylon-Insert Locknuts.
    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.
    Cadmium Yellow-Chromate-Plated Steel—These locknuts have good lubricity to thread on smoothly and ease installation. The plating also creates a barrier against rust that's comparable to zinc yellow-chromate plating.
    Thread
    Size
    Wd.
    Ht.
    Mil. Specs.
    Met
    Insert Max.
    Temp., ° F
    Specs.
    Met
    Pkg.
    Qty.
    Pkg.
    Cadmium Yellow-Chromate-Plated Steel
    6-32
    		5/16"9/64"MS21083N06250NASM2108310000000000000000
     
    Corrosion-Resistant Stainless Steel
    Image of Product. Front orientation. Locknuts. Mil. Spec. Thin-Profile Nylon-Insert Locknuts.
    18-8 Stainless Steel—The choice for wet and outdoor environments, these locknuts resist rust. However, they won't hold up to the harsh chemicals that 316 stainless steel can.
    Thread
    Size
    Wd.
    Ht.
    Mil. Specs.
    Met
    Insert Max.
    Temp., ° F
    Specs.
    Met
    Pkg.
    Qty.
    Pkg.
    18-8 Stainless Steel
    6-32
    		5/16"9/64"MS21083C06250NASM2108310000000000000000
     

    Thin-Profile Flex-Top Locknuts for Heavy Vibration
    3D CAD models available

    About two-thirds the height of standard flex-top nuts, these fit in spaces with low clearance. You can also use them as jam nuts by threading them against a hex nut to hold it in place. The top section expands to grip the screw on all sides for a stronger hold than both nylon-insert and distorted-thread locknuts. As a result, they're suitable for use in equipment with constant, vigorous vibration, such as engines. These locknuts are reusable a handful of times, but the holding power decreases with each use.
    Steel
    Image of Product. Front orientation. Locknuts. Thin-Profile Flex-Top Locknuts for Heavy Vibration.
    These locknuts have equivalent strength to Grade 8 and Class 10 steel nuts. To avoid stripped threads during installation, make sure your screw has a comparable strength rating.
    Cadmium-Plated Steel—These locknuts have good lubricity to thread on smoothly and ease installation. The plating also creates a barrier against rust that's comparable to zinc yellow-chromate plating.
    Steel—Best for dry environments since moisture will cause these nuts to rust.
    Thread
    Size
    Wd.
    Ht.
    Pkg.
    Qty.
    Pkg.
    Cadmium-Plated Steel
    6-32
    		5/16"9/64"25000000000000000
     
    Steel
    6-32
    		5/16"9/64"100000000000000
     
    Corrosion-Resistant Stainless Steel
    Image of Product. Front orientation. Locknuts. Thin-Profile Flex-Top Locknuts for Heavy Vibration.
    18-8 Stainless Steel—The choice for wet and outdoor environments, these locknuts resist rust. However, they won't hold up to the harsh chemicals that 316 stainless steel can.
    Thread
    Size
    Wd.
    Ht.
    Pkg.
    Qty.
    Pkg.
    18-8 Stainless Steel
    6-32
    		5/16"9/64"10000000000000000
     

    Knurled-Head Thumb Nuts
    3D CAD models available

    Image of Attribute. Front orientation. Contains Annotated. Thumb Nuts. Knurled-Head Thumb Nuts.
    Get a good grip on these nuts, even with oily fingers. They have a raised, slip-resistant head, so you can tighten them by hand and make controlled adjustments. Knurled-head nuts have a smaller profile than wing nuts, so they fit in tighter spots.
    Corrosion-Resistant 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.
    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 316 Stainless Steel—Our most corrosion-resistant thumb nuts, these hold up in just about any environment. They won't degrade from exposure to weather, salt water, and most chemicals.
    Collar
    Thread
    Size
    Dia.
    Ht.
    Head
    Dia.
    Ht.
    Threading
    Thread
    Dp.
    Pkg.
    Qty.
    Pkg.
    18-8 Stainless Steel
    6-32
    		1/4"1/4"1/2"3/8"Partially Threaded9/32"100000000000000
    6-32
    		1/4"1/4"3/4"3/8"Partially Threaded9/32"10000000000000
    6-32
    		1/4"1/2"1/2"5/8"Partially Threaded11/32"10000000000000
    6-32
    		1/4"1/2"3/4"5/8"Fully Threaded__10000000000000
     
    Black-Oxide 18-8 Stainless Steel
    6-32
    		1/4"1/4"1/2"3/8"Partially Threaded3/32"10000000000000
     
    Super-Corrosion-Resistant 316 Stainless Steel
    6-32
    		1/4"1/4"3/4"3/8"Fully Threaded__10000000000000
     
    Plastic
    Reinforced Acetal—The best plastic for damp and wet environments, acetal won't swell or lose strength if exposed to moisture. These nuts are reinforced with an aluminum threaded insert, so they can handle more torque than other plastic nuts and won't crack during installation.
    Nylon—These nuts thread on smoothly and resist abrasion to stand up to scratches and bumps. Nylon will swell and weaken when exposed to moisture, so it's best for dry environments.
    Collar
    Thread
    Size
    Dia.
    Ht.
    Head
    Dia.
    Ht.
    Color
    Threading
    Insert
    Material
    Pkg.
    Qty.
    Pkg.
    Reinforced Acetal
    6-32
    		23/64"3/64"3/8"7/32"BlackFully ThreadedAluminum
    		1000000000000000
     
    Nylon
    6-32
    		1/4"1/4"1/2"3/8"BlackFully Threaded__10000000000000
    6-32
    		1/4"1/4"3/4"3/8"BlackFully Threaded__10000000000000
     

    Flanged Knurled-Head Thumb Nuts
    3D CAD models available

    Image of Attribute. Front orientation. Contains Annotated. Thumb Nuts. Flanged Knurled-Head Thumb Nuts.
    The slip-resistant head is easy to grip, while the flange distributes pressure evenly across the mounting surface without the need for a separate washer. These nuts are often used to secure screws in oversized or irregularly shaped holes since the flange covers a larger area than standard nuts.
    Corrosion-Resistant 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.
    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 316 Stainless Steel—Our most corrosion-resistant thumb nuts, these hold up in just about any environment. They won't degrade from exposure to weather, salt water, and most chemicals.
    Collar
    Thread
    Size
    Dia.
    Ht.
    Head
    Dia.
    Ht.
    Threading
    Pkg.
    Qty.
    Pkg.
    18-8 Stainless Steel
    6-32
    		11/32"5/32"3/8"9/32"Fully Threaded100000000000000
     
    Black-Oxide 18-8 Stainless Steel
    6-32
    		11/32"5/32"3/8"9/32"Fully Threaded10000000000000
     
    Passivated 18-8 Stainless Steel
    6-32
    		11/32"5/32"3/8"9/32"Fully Threaded10000000000000
     
    Super-Corrosion-Resistant 316 Stainless Steel
    6-32
    		11/32"5/32"3/8"9/32"Fully Threaded100000000000000
     
    Brass
    Brass—With a warm, polished look, these nuts are often chosen for their appearance. Similar to 18-8 stainless steel, brass is corrosion resistant enough to stand up to wet environments. It is also softer than other metals, so it's easier to thread together.
    Collar
    Thread
    Size
    Dia.
    Ht.
    Head
    Dia.
    Ht.
    Threading
    Pkg.
    Qty.
    Pkg.
    Brass
    6-32
    		5/16"9/64"3/8"1/4"Fully Threaded25000000000000000
     

    Hex-Head Thumb Nuts
    3D CAD models available

    Apply extra torque to these nuts to prevent accidental loosening. Twist them on by hand, then crank with a wrench for a tight fit. The flange distributes pressure evenly across the mounting surface without the need for a separate washer. These nuts are often used to secure screws in oversized or irregularly shaped holes since the flange covers a larger area than standard nuts.
    Corrosion-Resistant Stainless Steel
    Image of Product. Front orientation. Contains Annotated. Thumb Nuts. Hex-Head Thumb 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.
    Collar
    Thread
    Size
    Dia.
    Ht.
    Wd.
    Ht.
    Pkg.
    Qty.
    Pkg.
    18-8 Stainless Steel
    6-32
    		11/32"5/32"3/8"9/32"100000000000000
     
    back to top