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    101 Products

    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 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.
    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.
    Steel—Best for dry environments since moisture will cause these nuts to rust.
    Material Certificate Icon
    Certificates with a traceable lot number are available for these products. Download certificates from ORDER HISTORY after your order ships.
    Small Pack
    Thread
    Size
    Wd.
    Ht.
    Fastener Strength
    Grade/Class
    Insert Max.
    Temp., ° F
    Certificate Type
    Pkg.
    Qty.
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    Zinc-Yellow-Chromate-Plated Steel
    5/16"-18
    		1/2"11/32"SAE Grade 8
    		185Material Certificate
    		2097135A22000000
     
    Black-Oxide Steel
    5/16"-18
    		1/2"11/32"SAE Grade 8
    		185Material Certificate
    		2097135A4160000
     
    Steel
    5/16"-18
    		1/2"11/32"SAE Grade 8
    		185Material Certificate
    		2090630A1150000
     
    Medium-Strength Steel
    Image of Product. Front orientation. Locknuts. Nylon-Insert Locknuts.
    These Grade 5, Grade C, 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.
    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.
    Small Pack
    Thread
    Size
    Wd.
    Ht.
    Fastener Strength
    Grade/Class
    Insert Max.
    Temp., ° F
    Certificate Type
    Pkg.
    Qty.
    Pkg.
    Zinc-Plated Steel
    5/16"-18
    		1/2"11/32"SAE Grade 5
    		185Material Certificate
    		10095615A160000000
     
    Black-Oxide Steel
    5/16"-18
    		1/2"11/32"SAE Grade 5
    		185—10095615A10300000
     
    Low-Strength Steel
    Image of Product. Front orientation. Locknuts. 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-Corrosion-Resistant-Coated 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
    Certificate Type
    Pkg.
    Qty.
    Pkg.
    Zinc-Plated Steel
    5/16"-18
    		1/2"11/32"185Material Certificate
    		10090640A13000000
     
    Black-Corrosion-Resistant-Coated Steel
    5/16"-18
    		1/2"11/32"185—591333A1600000
     
    Corrosion-Resistant Stainless Steel
    Image of Product. Front orientation. Locknuts. 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.
    316 Stainless Steel—Our most corrosion-resistant nuts, these hold up in just about any environment. They won't degrade from exposure to weather, salt water, and most chemicals.
    Large Pack—Priced at least 30% lower per locknut than small packs.
    Small Pack
    Large Pack
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    Pkg.
    Qty.
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    18-8 Stainless Steel
    5/16"-18
    		1/2"11/32"185—5091831A030000000————0
    5/16"-18
    		1/2"11/32"185Material Certificate
    		————01,00091831A0080000000
     
    Black-Oxide 18-8 Stainless Steel
    5/16"-18
    		1/2"11/32"185Material Certificate
    		5094407A10500000————0
     
    316 Stainless Steel
    5/16"-18
    		1/2"11/32"185Material Certificate
    		5090715A135000001,00090715A046000000
     
    High-Strength Lightweight Titanium
    Image of Product. Front orientation. Locknuts. Nylon-Insert Locknuts.
    Grade 5 Titanium—The best of both worlds, these locknuts are lightweight like aluminum and as corrosion-resistant as 316 stainless steel. They're ideal for use in chemical-processing and water-treatment facilities since they stand up to strong acids and other harsh chemicals. Grade 5 is the strongest of all the titanium alloys due to its higher aluminum and vanadium content.
    Thread
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    Temp.
    Pkg.
    Qty.
    Pkg.
    Grade 5 Titanium
    5/16"-18
    		1/2"11/32"Not Rated194528A11800000
     
    Lightweight Aluminum
    Image of Product. Front orientation. Locknuts. Nylon-Insert Locknuts.
    6061 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.
    Material Certificate Icon
    Certificates with a traceable lot number are available for these products. Download certificates from ORDER HISTORY after your order ships.
    Small Pack
    Thread
    Size
    Wd.
    Ht.
    Insert Max.
    Temp., ° F
    Certificate Type
    Pkg.
    Qty.
    Pkg.
    6061 Aluminum
    5/16"-18
    		1/2"11/32"185Material Certificate
    		2595856A25500000
     
    Brass
    Image of Product. Front orientation. Locknuts. Nylon-Insert Locknuts.
    Brass—Conductive and nonmagnetic, brass locknuts are typically 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.
    Insert Max.
    Temp., ° F
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    Brass
    5/16"-18
    		1/2"11/32"1851092092A030000000
     

    Serrated Flange Nuts

    Serrations bite into material for mild vibration resistance while the flange eliminates the need for a separate washer. These nuts are ideal for securing screws in oversized or irregularly shaped holes since the flange covers a larger area than standard nuts. You can use them again and again without sacrificing strength. However, the serrations may mar the surface of your material. Also known as collar nuts.
    Medium-Strength Steel
    Image of Product. Bottom orientation. Flange Nuts. Serrated Flange Nuts.
    Rated Grade 5, Grade F, or Class 8, these 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.
    Black-Oxide Steel—Typically chosen for their appearance, these nuts have a dark, matte coating that creates a finished look. They offer minimal corrosion resistance, so they're best for dry environments.
    Flange
    Thread
    Size
    Wd.
    Ht.
    Dia.
    Thk.
    Fastener Strength
    Grade/Class
    Certificate Type
    Pkg.
    Qty.
    Pkg.
    Zinc-Plated Steel
    5/16"-18
    		1/2"9/32"11/16"0.04"SAE Grade 5
    		Material Certificate
    		10099904A102000000
     
    Black-Oxide Steel
    5/16"-18
    		1/2"9/32"43/64"0.04"SAE Grade 5
    		—10099904A21200000
     
    High-Strength Steel
    Image of Product. Bottom orientation. Flange Nuts. Serrated Flange Nuts.
    Rated Grade 8, Grade G, or Class 10, these are about 25% stronger than medium-strength steel nuts. They are commonly used to fasten components in valves, pumps, and motors. 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 Phosphate-Coated Steel—The dark coating creates both a finished appearance and a barrier against rust that withstands occasional exposure to moisture.
    Steel—Best for dry environments since moisture will cause these nuts to rust.
    Flange
    Thread
    Size
    Wd.
    Ht.
    Dia.
    Thk.
    Fastener Strength
    Grade/Class
    Certificate Type
    Pkg.
    Qty.
    Pkg.
    Zinc-Plated Steel
    5/16"-18
    		1/2"9/32"11/16"0.04"SAE Grade 8
    		Material Certificate
    		10096282A102000000
     
    Black Phosphate-Coated Steel
    5/16"-18
    		1/2"9/32"11/16"0.04"SAE Grade 8
    		—2595922A1120000
     
    Steel
    5/16"-18
    		1/2"9/32"43/64"0.04"SAE Grade 8
    		—10095922A12000000
     
    Low-Strength Steel
    Image of Product. Bottom orientation. Flange Nuts. Serrated Flange Nuts.
    About half the strength of medium-strength steel nuts, these 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-Oxide Steel—Typically chosen for their appearance, these nuts have a dark, matte coating that creates 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.
    Flange
    Thread
    Size
    Wd.
    Ht.
    Dia.
    Thk.
    Certificate Type
    Pkg.
    Qty.
    Pkg.
    Zinc-Plated Steel
    5/16"-18
    		1/2"9/32"43/64"0.04"Material Certificate
    		10094831A03000000
    5/16"-18
    		1/2"23/64"13/16"0.04"Material Certificate
    		10090659A10200000
     
    Black-Oxide Steel
    5/16"-18
    		1/2"9/32"11/16"0.04"—5093083A1060000
     
    Zinc-Flake-Coated Steel
    5/16"-18
    		1/2"9/32"43/64"0.04"Material Certificate
    		1092058A1700000
     
    Corrosion-Resistant Stainless Steel
    Image of Product. Bottom orientation. Flange Nuts. Serrated Flange 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.
    Highly Corrosion-Resistant 316 Stainless Steel—Our most corrosion-resistant flange nuts, these hold up in just about any environment, including harsh weather, salt water, and most chemicals.
    Material Certificate Icon
    Certificates with a traceable lot number are available for these products. Download certificates from ORDER HISTORY after your order ships.
    Flange
    Thread
    Size
    Wd.
    Ht.
    Dia.
    Thk.
    Certificate Type
    Pkg.
    Qty.
    Pkg.
    18-8 Stainless Steel
    5/16"-18
    		1/2"9/32"43/64"0.11"Material Certificate
    		2593776A44100000
     
    Highly Corrosion-Resistant 316 Stainless Steel
    5/16"-18
    		1/2"9/32"11/16"0.04"Material Certificate
    		1091343A2000000
     
    Brass
    Image of Product. Bottom orientation. Flange Nuts. Serrated Flange 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.
    Flange
    Thread
    Size
    Wd.
    Ht.
    Dia.
    Thk.
    Pkg.
    Qty.
    Pkg.
    Brass
    5/16"-18
    		1/2"9/32"43/64"0.04"593051A120000000
     

    Thin-Profile Nylon-Insert Locknuts

    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.
    High-Strength Steel
    Image of Product. Front orientation. Locknuts. Thin-Profile Nylon-Insert Locknuts.
    Rated Grade 8 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.
    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.
    Material Certificate Icon
    Certificates with a traceable lot number are available for these products. Download certificates from ORDER HISTORY after your order ships.
    Thread
    Size
    Wd.
    Ht.
    Fastener Strength
    Grade/Class
    Insert Max.
    Temp.
    Certificate Type
    Pkg.
    Qty.
    Pkg.
    Zinc-Yellow-Chromate-Plated Steel
    5/16"-18
    		1/2"1/4"SAE Grade 8
    		Not RatedMaterial Certificate
    		10094945A213000000
     
    Black-Oxide Steel
    5/16"-18
    		1/2"1/4"SAE Grade 8
    		250° FMaterial Certificate
    		2594945A13300000
     
    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—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
    Certificate Type
    Pkg.
    Qty.
    Pkg.
    Zinc-Plated Steel
    5/16"-18
    		1/2"1/4"220Material Certificate
    		10090566A03000000
     
    Black-Zinc-Plated Steel
    5/16"-18
    		1/2"1/4"220—1094627A1700000
     
    Black-Corrosion-Resistant-Coated Steel
    5/16"-18
    		1/2"1/4"220—591581A3650000
     
    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.
    316 Stainless Steel—Our most corrosion-resistant nuts, these hold up in just about any environment. They won't degrade from exposure to weather, salt water, and most chemicals.
    Thread
    Size
    Wd.
    Ht.
    Insert Max.
    Temp., ° F
    Certificate Type
    Pkg.
    Qty.
    Pkg.
    18-8 Stainless Steel
    5/16"-18
    		1/2"1/4"220Material Certificate
    		5090101A237000000
     
    Black-Oxide 18-8 Stainless Steel
    5/16"-18
    		1/2"1/4"220—5090101A12200000
     
    316 Stainless Steel
    5/16"-18
    		1/2"1/4"220—2597367A11400000
     

    Nylon-Insert Flange Nuts

    A nylon insert grips the screw for a stronger hold than a serrated flange, without damaging threads or marring the surface of your material. However, the insert may become brittle if exposed to high temperatures. These nuts have a flange that distributes pressure evenly across the mounting surface, so you don't need a separate washer. They are ideal for securing screws in oversized or irregularly shaped holes since the flange covers a larger area than standard nuts. You can reuse them a handful of times, but their holding power will decrease with each use. Also known as collar nuts.
    Medium-Strength Steel
    Image of Product. Front orientation. Flange Nuts. Nylon-Insert Flange Nuts.
    Rated Grade 5, Grade F, or Class 8, these 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.
    Black-Oxide Steel—Typically chosen for their appearance, these nuts have a dark, matte coating that creates a finished look. They offer minimal corrosion resistance, so they're best for dry environments.
    Material Certificate Icon
    Certificates with a traceable lot number are available for these products. Download certificates from ORDER HISTORY after your order ships.
    Flange
    Thread
    Size
    Wd.
    Ht.
    Dia.
    Thk.
    Fastener Strength
    Grade/Class
    Certificate Type
    Insert Max.
    Temp., ° F
    Pkg.
    Qty.
    Pkg.
    Zinc-Plated Steel
    5/16"-18
    		1/2"11/32"0.68"0.05"ASME Grade F
    		Material Certificate
    		2505093298A12000000
     
    Black-Oxide Steel
    5/16"-18
    		1/2"11/32"0.68"0.05"ASME Grade F
    		Material Certificate
    		2505093298A20400000
     
    High-Strength Steel
    Image of Product. Front orientation. Flange Nuts. Nylon-Insert Flange Nuts.
    Rated Grade 8, Grade G, or Class 10, these are about 25% stronger than medium-strength steel nuts. They are commonly used to fasten components in valves, pumps, and motors. 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 that creates a finished look. They offer minimal corrosion resistance, so they're best for dry environments.
    Flange
    Thread
    Size
    Wd.
    Ht.
    Dia.
    Thk.
    Fastener Strength
    Grade/Class
    Certificate Type
    Insert Max.
    Temp., ° F
    Pkg.
    Qty.
    Pkg.
    Zinc-Yellow-Chromate-Plated Steel
    5/16"-18
    		1/2"11/32"0.68"0.05"ASME Grade G
    		—2505092018A32000000
     
    Black-Oxide Steel
    5/16"-18
    		1/2"23/64"0.68"0.05"ASME Grade G
    		Material Certificate
    		25010092018A11400000
     
    Corrosion-Resistant Stainless Steel
    Image of Product. Front orientation. Flange Nuts. Nylon-Insert Flange 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 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.
    Flange
    Thread
    Size
    Wd.
    Ht.
    Dia.
    Thk.
    Certificate Type
    Insert Max.
    Temp., ° F
    Pkg.
    Qty.
    Pkg.
    18-8 Stainless Steel
    5/16"-18
    		1/2"11/32"0.68"0.05"Material Certificate
    		2502594238A102000000
     
    Black-Oxide 18-8 Stainless Steel
    5/16"-18
    		1/2"3/8"0.675"0.1"—250194238A3300000
     

    Top-Lock Distorted-Thread Locknuts

    Image of Product. Front orientation. Locknuts. Top-Lock Distorted-Thread Locknuts.
    Irregularly shaped threads at the top of these locknuts grip the screw for a stronger hold than nylon-insert locknuts. Although the threads prevent the nut from backing out due to vibration, 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. Nuts are not reusable.
    Extreme-Strength Steel
    About 20% stronger than high-strength steel locknuts, these Grade 9 nuts are the strongest we offer. Make sure to use them with Grade 9 screws to avoid stripped threads during installation.
    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.
    Thread
    Size
    Wd.
    Ht.
    Fastener Strength
    Grade/Class
    Pkg.
    Qty.
    Pkg.
    Cadmium-Plated Steel
    5/16"-18
    		1/2"21/64"SAE Grade 9
    		2593591A200000000
     
    Medium-Strength Steel
    These Grade 5, Grade C, 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-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.
    Zinc-Plated Steel—A step up from plain steel, the zinc plating withstands occasional exposure to moisture.
    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, this multilayer finish resists wear for long-term rust protection. However, similar to zinc-yellow-chromate plating, it won't hold up to harsh chemicals like stainless steel can.
    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.
    Fastener Strength
    Grade/Class
    Certificate Type
    Pkg.
    Qty.
    Pkg.
    Zinc-Yellow-Chromate-Plated Steel
    5/16"-18
    		1/2"17/64"ASTM Grade C
    		—5099291A12000000
     
    Zinc-Plated Steel
    5/16"-18
    		1/2"17/64"ASTM Grade C
    		—10092501A52300000
    5/16"-18
    		1/2"19/64"SAE Grade 5
    		Material Certificate
    		5095065A16000000
     
    Black-Oxide Steel
    5/16"-18
    		1/2"17/64"ASTM Grade C
    		—5099291A34000000
    5/16"-18
    		1/2"19/64"SAE Grade 5
    		—5090673A10200000
     
    Zinc-Flake-Coated Steel
    5/16"-18
    		1/2"17/64"ASTM Grade C
    		—1099291A5600000
     
    Cadmium-Plated Steel
    5/16"-18
    		1/2"17/64"ASTM Grade C
    		—10092501A03000000
     
    Steel
    5/16"-18
    		1/2"17/64"ASTM Grade C
    		—10092501A5030000
     
    Low-Strength Steel
    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.
    Fastener Strength
    Grade/Class
    Pkg.
    Qty.
    Pkg.
    Zinc-Plated Steel
    5/16"-18
    		1/2"17/64"SAE Grade 2
    		10091837A030000000
     
    Corrosion-Resistant Stainless Steel
    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.
    316 Stainless Steel—Our most corrosion-resistant nuts, these hold up in just about any environment. They won't degrade from exposure to weather, salt water, and most chemicals.
    Thread
    Size
    Wd.
    Ht.
    Pkg.
    Qty.
    Pkg.
    18-8 Stainless Steel
    5/16"-18
    		1/2"17/64"2590045A45300000
     
    316 Stainless Steel
    5/16"-18
    		1/2"17/64"1095885A4300000
     

    Distorted-Thread Flange Nuts

    Image of Product. Bottom orientation. Flange Nuts. Distorted-Thread Flange Nuts.
    The strongest hold of all the flange nuts we offer, these have irregularly shaped threads that grip the screw to resist loosening. The threads prevent the nut from backing out due to high vibration, 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, so they are not reusable. Nuts have a flange that distributes pressure evenly across the mounting surface without the need for a separate washer. They are ideal for securing screws in oversized or irregularly shaped holes since the flange covers a larger area than standard nuts. Also known as collar nuts.
    Medium-Strength Steel
    Rated Grade 5, Grade F, or Class 8, these 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.
    Black Phosphate-Coated Steel—The dark coating creates both a finished appearance and a barrier against rust that withstands occasional exposure to moisture.
    Flange
    Thread
    Size
    Wd.
    Ht.
    Dia.
    Thk.
    Fastener Strength
    Grade/Class
    Pkg.
    Qty.
    Pkg.
    Zinc-Plated Steel
    5/16"-18
    		1/2"9/32"11/16"0.05"SAE Grade 5
    		10090426A33000000
     
    Black Phosphate-Coated Steel
    5/16"-18
    		1/2"9/32"11/16"0.05"SAE Grade 5
    		10090426A2200000
     
    High-Strength Steel
    Rated Grade 8, Grade G, or Class 10, these are about 25% stronger than medium-strength steel nuts. They are commonly used to fasten components in valves, pumps, and motors. 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 that creates a finished look. They offer minimal corrosion resistance, so they're best for dry environments.
    Black Phosphate-Coated Steel—The dark coating creates both a finished appearance and a barrier against rust that withstands occasional exposure to moisture.
    Flange
    Thread
    Size
    Wd.
    Ht.
    Dia.
    Thk.
    Fastener Strength
    Grade/Class
    Pkg.
    Qty.
    Pkg.
    Zinc-Yellow-Chromate-Plated Steel
    5/16"-18
    		1/2"23/64"11/16"0.05"ASME Grade G
    		2590949A214000000
     
    Black-Oxide Steel
    5/16"-18
    		1/2"23/64"11/16"0.05"ASME Grade G
    		2590949A22600000
     
    Black Phosphate-Coated Steel
    5/16"-18
    		1/2"23/64"11/16"0.05"ASME Grade G
    		10090949A02500000
     
    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.
    Flange
    Thread
    Size
    Wd.
    Ht.
    Dia.
    Thk.
    Pkg.
    Qty.
    Pkg.
    18-8 Stainless Steel
    5/16"-18
    		1/2"9/32"0.68"0.04"1098892A13200000
     

    Center-Lock Distorted-Thread Locknuts

    Image of Product. Front orientation. Locknuts. Center-Lock Distorted-Thread Locknuts.
    Also known as reversible locknuts, these thread on from either side, so you don't have to worry about fastening them incorrectly and damaging your screw. The irregularly shaped threads in the middle grip the screw for a stronger hold than nylon-insert locknuts. Although the threads prevent the nut from backing out due to vibration, 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. Nuts are not reusable.
    High-Strength Steel
    Rated Grade 8 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.
    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, this multilayer finish resists wear for long-term rust protection. However, similar to zinc-yellow-chromate plating, it won't hold up to harsh chemicals like stainless steel can.
    Thread
    Size
    Wd.
    Ht.
    Fastener Strength
    Grade/Class
    Certificate Type
    Pkg.
    Qty.
    Pkg.
    Zinc-Yellow-Chromate-Plated Steel
    5/16"-18
    		1/2"17/64"SAE Grade 8
    		Material Certificate
    		5090636A043000000
     
    Black-Oxide Steel
    5/16"-18
    		1/2"17/64"SAE Grade 8
    		—1090636A1130000
     
    Zinc-Flake-Coated Steel
    5/16"-18
    		1/2"17/64"SAE Grade 8
    		—1090636A12200000
     
    Low-Strength Steel
    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.
    Fastener Strength
    Grade/Class
    Pkg.
    Qty.
    Pkg.
    Zinc-Plated Steel
    5/16"-18
    		1/2"17/64"SAE Grade 2
    		10090040A030000000
     
    Corrosion-Resistant Stainless Steel
    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.
    316 Stainless Steel—Our most corrosion-resistant nuts, these hold up in just about any environment. They won't degrade from exposure to weather, salt water, and most chemicals.
    Thread
    Size
    Wd.
    Ht.
    Pkg.
    Qty.
    Pkg.
    18-8 Stainless Steel
    5/16"-18
    		1/2"17/64"5090047A115000000
     
    316 Stainless Steel
    5/16"-18
    		1/2"17/64"1095878A3100000
     

    Locknuts with External-Tooth Lock Washer

    Image of Product. Front orientation. ZoomedIn view. Locknuts. Locknuts with External-Tooth Lock Washer.
    To save on assembly time, these locknuts combine a hex nut with a free-spinning lock washer, so you can twist them into place by hand. Once the nut is against your material surface, tighten it down with a wrench or socket to get the teeth to bite. Although these nuts install more quickly than nylon-insert locknuts, they don't hold up as well against vibration and can mar your material. As long as the washer stays intact, you can reuse them. Also known as Keps and K-lock nuts.
    Material Certificate Icon
    Certificates with a traceable lot number are available for these products. Download certificates from ORDER HISTORY after your order ships.
    Low-Strength Steel
    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.
    Washer
    OD
    Certificate Type
    Pkg.
    Qty.
    Pkg.
    Zinc-Plated Steel
    5/16"-18
    		1/2"21/64"0.578"Material Certificate
    		10090675A030000000
     
    Corrosion-Resistant Stainless Steel
    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.
    Washer
    OD
    Certificate Type
    Pkg.
    Qty.
    Pkg.
    18-8 Stainless Steel
    5/16"-18
    		1/2"21/64"0.578"Material Certificate
    		2596278A519000000
     

    Flex-Top Locknuts for Heavy Vibration

    Image of Product. Front orientation. Locknuts. Flex-Top Locknuts for Heavy Vibration.
    The top section of these nuts expands to grip the screw on all sides for a stronger hold than both nylon-insert and distorted-thread locknuts. They’re often used 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
    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.
    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.
    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.
    Thread
    Size
    Wd.
    Ht.
    Pkg.
    Qty.
    Pkg.
    Black-Oxide Steel
    5/16"-18
    		1/2"23/64"594820A39000000
     
    Cadmium-Plated Steel
    5/16"-18
    		1/2"23/64"1094820A2370000
     
    Corrosion-Resistant Stainless Steel
    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
    5/16"-18
    		1/2"23/64"191839A12700000
     

    Mil. Spec. Nylon-Insert Locknuts

    These locknuts are manufactured and tested to strict U.S. military standards for material and construction. 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.
    Material Certificate Icon
    Certificates with a traceable lot number are available for these products. Download certificates from ORDER HISTORY after your order ships.
    Corrosion-Resistant Stainless Steel
    Image of Product. Front orientation. Locknuts. Mil. Spec. 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. Spec.
    Insert Max.
    Temp., ° F
    Certificate Type
    Pkg.
    Qty.
    Pkg.
    18-8 Stainless Steel
    5/16"-18
    		1/2"11/32"MS17830-5C, NASM17830250Material Certificate
    		596345A310000000
     

    Thin-Heavy-Profile Nylon-Insert Locknuts

    Image of Product. Front orientation. Locknuts. Thin-Heavy-Profile Nylon-Insert Locknuts.
    About half the height of standard-profile locknuts 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 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
    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-Corrosion-Resistant-Coated 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
    5/16"-18
    		9/16"5/16"25010090652A030000000
     
    Black-Corrosion-Resistant-Coated Steel
    5/16"-18
    		9/16"5/16"250590652A8200000
     
    Corrosion-Resistant Stainless Steel
    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.
    Insert Max.
    Temp., ° F
    Pkg.
    Qty.
    Pkg.
    18-8 Stainless Steel
    5/16"-18
    		9/16"5/16"2502090098A115000000
     

    Heavy-Profile Nylon-Insert Locknuts

    Image of Product. Front orientation. Locknuts. Heavy-Profile Nylon-Insert Locknuts.
    About 10% wider and taller than standard-profile locknuts, these handle heavier loads by distributing them over a larger area. 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
    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.
    Insert Max.
    Temp., ° F
    Pkg.
    Qty.
    Pkg.
    Zinc-Plated Steel
    5/16"-18
    		9/16"7/16"25010090648A030000000
     
    Corrosion-Resistant Stainless Steel
    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.
    Insert Max.
    Temp., ° F
    Pkg.
    Qty.
    Pkg.
    18-8 Stainless Steel
    5/16"-18
    		9/16"7/16"250590099A03000000
     

    Thin-Profile Flex-Top Locknuts for Heavy Vibration

    Image of Product. Front orientation. Locknuts. Thin-Profile Flex-Top Locknuts for Heavy Vibration.
    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
    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
    5/16"-18
    		1/2"17/64"1094830A52000000
     
    Steel
    5/16"-18
    		1/2"17/64"594830A1300000
     
    Corrosion-Resistant Stainless Steel
    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.
    Material Certificate Icon
    Certificates with a traceable lot number are available for these products. Download certificates from ORDER HISTORY after your order ships.
    Thread
    Size
    Wd.
    Ht.
    Certificate Type
    Pkg.
    Qty.
    Pkg.
    18-8 Stainless Steel
    5/16"-18
    		1/2"17/64"Material Certificate
    		194140A13900000
     

    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
     

    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
    Image of Product. Front orientation. Contains Annotated, Border. Cap Nuts. Cap Nuts with Threadlocker.
    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.
    Certificate Type
    Pkg.
    Qty.
    Pkg.
    18-8 Stainless Steel
    5/16"-18
    		19/64"1/2"17/32"Material Certificate
    		590421A160000000
     
    Highly Corrosion-Resistant 316 Stainless Steel
    5/16"-18
    		5/16"1/2"17/32"—193052A1400000
     

    Nylon-Insert Wing Nuts

    Image of Product. Front orientation. Thumb Nuts. Nylon-Insert Wing Nuts.
    The strongest hold of all our thumb nuts. The wings give you extra leverage for a tight fit, while a nylon insert grips the screw to prevent loosening from vibration. However, the insert may become brittle if exposed to high temperatures. You can reuse these nuts a handful of times, but their holding power will decrease with each use.
    Material Certificate Icon
    Certificates with a traceable lot number are available for these products. Download certificates from ORDER HISTORY after your order ships.
    Zinc Alloy
    Zinc—Zinc alloy nuts have better corrosion resistance than steel to withstand occasional exposure to moisture. However, they're not as strong.
    Thread
    Size
    Wd.
    Ht.
    Base
    Dia.
    Insert Max.
    Temp., ° F
    Pkg.
    Qty.
    Pkg.
    Zinc
    5/16"-18
    		1 1/2"23/32"9/16"2251098520A140000000
     

    Locknuts for use with Cotter Pins

    Image of ProductInUse. Front orientation. Locknuts. Locknuts for use with Cotter Pins.
    Image of Product. Front orientation. Locknuts. 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.
    Medium-Strength Steel
    These Grade 5, Grade C, 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.
    Thread
    Size
    Wd.
    Ht.
    Fastener Strength
    Grade/Class
    For Cotter
    Pin Dia.
    Pkg.
    Qty.
    Pkg.
    Zinc-Plated Steel
    5/16"-18
    		1/2"17/64"SAE Grade 5
    		5/64"2597190A010000000
     
    Low-Strength Steel
    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
    5/16"-18
    		1/2"17/64"5/64"2595030A13000000
     
    Corrosion-Resistant Stainless Steel
    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.
    For Cotter
    Pin Dia.
    Pkg.
    Qty.
    Pkg.
    18-8 Stainless Steel
    5/16"-18
    		1/2"21/64"5/64"591853A030000000
     

    Serrated Locknuts

    Image of Product. Front orientation. Locknuts. Serrated Locknuts.
    Since these nuts twist on by hand and don't require much torque, they're the easiest locknuts to install. The serrated edge grips surfaces to secure equipment that experiences mild vibration, such as panel covers and small electric motors. You can reuse these locknuts over and over again, but the serrations may mar your surface.
    Low-Strength Steel
    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.
    Pkg.
    Qty.
    Pkg.
    Zinc-Plated Steel
    5/16"-18
    		1/2"17/64"5091762A150000000
     

    Weld Locknuts

    Image of Product. Bottom orientation. Weld Nuts. Weld Locknuts.
    Image of Product. Bottom orientation. Weld Nuts. Weld Locknuts.
    Prevent screws from backing out under heavy vibration. These nuts have distorted threads that grip screws tightly. Three evenly spaced projections concentrate heat away from the threads to prevent them from deforming and create consistent welds. These nuts also have a collar pilot that guides the nut into the hole, holds it in place while welding, and protects the threads from weld spatter.
    Use Grade 2 or Class 6 screws to avoid stripping threads during installation. Distorted threads require high torque for fastening and unfastening, so you may need an impact wrench to remove screws.
    Steel—Best for dry environments since moisture will cause them to rust. Made of uncoated steel, these nuts require minimal prep. Weld them to uncoated steel surfaces.
    Collar
    Thread
    Size
    Wd.
    Ht.
    Dia.
    Ht.
    For Hole
    Dia.
    Pkg.
    Qty.
    Pkg.
    Steel
    5/16"-18
    		35/64"13/64"15/32"0.04"31/64"10090744A250000000
    5/16"-18
    		9/16"7/32"15/32"0.085"31/64"1090744A3500000
     

    Thick-Wall Highly Twist-Resistant Rivet Locknuts

    Image of Product. Bottom orientation. Rivet Nuts. Thick-Wall Highly Twist-Resistant Rivet Locknuts.
    Image of Attribute. Front orientation. Contains Annotated. Rivet Nuts. Thick-Wall Highly Twist-Resistant Rivet Locknuts.
    Keep screws locked in place with nuts that won't budge. Irregularly shaped threads stop screws from loosening under vibration and the hex-shaped body holds the nut in place when turning screws. With thick walls that distribute heavy loads better than standard walls, these nuts are strong enough for heavy machinery such as forklifts. The screw-locking threads require high torque, so you may need an impact wrench to remove screws.
    Install these nuts in a drilled or punched round hole using a rivet nut tool. Choose an air- or battery-powered tool for faster installation or to install many different nut sizes. Length is measured from under the flange.
    Zinc-Plated Steel—A step up from plain steel, the plating withstands occasional exposure to moisture.
    Flange
    Thread
    Size
    Wd. Across
    Flats
    For Material
    Thk.
    Body
    Dia.
    Lg.
    Installed
    Lg.
    Dia.
    Thk.
    Pkg.
    Qty.
    Pkg.
    Zinc-Plated Steel
    5/16"-18
    		7/16"0.031" to 0.157"0.432"0.771"0.535"0.63"0.059"1092009A14000000
    5/16"-18
    		7/16"0.157" to 0.276"0.432"0.897"0.535"0.63"0.059"1092009A1500000
     

    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.
    Certificate Type
    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"Material Certificate
    		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
     

    Serrated-Edge-Drive Tamper-Resistant Nuts

    Image of Product. Front orientation. Tamper-Resistant Nuts. Serrated-Edge-Drive Tamper-Resistant Nuts.
    These nuts have serrations that dig into the material surface to resist loosening and are narrow to fit in tight spaces. They must be installed with a nutdriver (sold separately). Use them to reduce the risk of unwanted removal for objects in public spaces such as signs, lighting fixtures, and displays.
    Aluminum—Aluminum nuts are lightweight, corrosion resistant in wet environments, and nonmagnetic.
    Nuts
    Serrated-Edge
    Nutdrivers
    Thread
    Size
    Dia.
    Ht.
    Pkg.
    Qty.
    Pkg.
    Each
    Aluminum
    5/16"-18
    		1/2"3/16"1098577A1300000098577A200000000
     

    Heavy-Profile Flex-Top Locknuts for Heavy Vibration

    Image of Product. Front orientation. Locknuts. Heavy-Profile Flex-Top Locknuts for Heavy Vibration.
    About 10% wider and taller than standard flex-top nuts, these handle heavier loads by distributing them over a larger area. 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
    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.
    Thread
    Size
    Wd.
    Ht.
    Pkg.
    Qty.
    Pkg.
    Cadmium-Plated Steel
    5/16"-18
    		9/16"21/64"1094827A120000000
     
    Corrosion-Resistant Stainless Steel
    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
    5/16"-18
    		9/16"21/64"195070A310000000
     

    Thin-Heavy-Profile Flex-Top Locknuts for Heavy Vibration

    Image of Product. Front orientation. Locknuts. Thin-Heavy-Profile Flex-Top Locknuts for Heavy Vibration.
    About two-thirds the height of standard flex-top nuts and 10% wider, these fit in spaces with low clearance and handle heavier loads by distributing them over a larger area. Because of the thin profile, 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
    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.
    Thread
    Size
    Wd.
    Ht.
    Pkg.
    Qty.
    Pkg.
    Cadmium-Plated Steel
    5/16"-18
    		9/16"17/64"1094828A420000000
     

    Steel Serrated-Flange Hex Head Screw and Nut Assortments

    Image of Product. Front orientation. Hex Head Screws. Steel Serrated-Flange Hex Head Screw and Nut Assortments.
    Image of Specification. Front orientation. SAE Grade 5. Serrated Locking.

    SAE

    Grade 5

    Stock up on fasteners in various sizes to create vibration-resistant joints. The screws and nuts in these assortments both have a flange with a serrated edge that grips your material to keep screws in place. The screws have a head with six flat sides to keep wrenches and sockets from slipping and rounding off the drive.
    Head height includes the flange. Length is measured from under the flange.
    Medium-Strength Fastener—Your go-to screws for fastening most machinery and equipment. They have tensile strengths from 90,000 to 120,000 psi.
    Zinc-Plated Steel—A common choice for areas with occasional exposure to moisture.
    No. of
    Pieces
    Serrated-Flange Hex Head Screws Included
    Serrated Flange Nuts Included
    Fastener Strength
    Grade/Class
    Container
    Type
    Each
    Medium-Strength Zinc-Plated Steel
    4901/4"-20 Thread: 1/2", 3/4", 1", 1 1/2", and 2" Lg. (140 Pieces)
    5/16"-18 Thread: 3/4", 1", 1 1/2", and 2" Lg. (100 Pieces)
    3/8"-16 Thread: 3/4", 1", 1 1/2", and 2" Lg. (70 Pieces)    		1/4"-20 Thread (80 Pieces)
    5/16"-18 Thread (60 Pieces)
    3/8"-16 Thread (40 Pieces)    		SAE Grade 5
    		Metal Box91638A1130000000
     

    Stainless Steel Serrated-Flange Hex Head Screw and Nut Assortments

    Image of Product. Front orientation. Hex Head Screws. Stainless Steel Serrated-Flange Hex Head Screw and Nut Assortments.
    Keep assorted corrosion-resistant fasteners on hand to create vibration-resistant joints. The screws and nuts in these assortments both have a flange with a serrated edge that grips your material to keep screws in place. The screws have a head with six flat sides to keep wrenches and sockets from slipping and rounding off the drive.
    Head height includes the flange. Length is measured from under the flange.
    18-8 Stainless Steel—The choice for wet and outdoor environments, these screws won't rust. However, they don't hold up to the harsh chemicals that 316 stainless steel screws can.
    No. of
    Pieces
    Serrated-Flange Hex Head Screws Included
    Serrated Flange Nuts Included
    Container
    Type
    Each
    18-8 Stainless Steel
    4901/4"-20 Thread: 1/2", 3/4", 1", 1 1/2", and 2" Lg. (140 Pieces)
    5/16"-18 Thread: 3/4", 1", 1 1/2", and 2" Lg. (100 Pieces)
    3/8"-16 Thread: 3/4", 1", 1 1/2", and 2" Lg. (70 Pieces)    		1/4"-20 Thread (80 Pieces)
    5/16"-18 Thread (60 Pieces)
    3/8"-16 Thread (40 Pieces)    		Metal Box91638A1120000000
     
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