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About Hex Head Screws and Bolts
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Choose a hex head fastener with the right threading, thread size, material, and strength for your equipment.
High-Pressure Steel Heavy Hex Head Screws
 |
Fully Threaded |
 |
Partially Threaded |
Meet ASTM standards for use in high-pressure and high-temperature applications. Also known as pressure bolts, these screws are often used to secure pressure tanks, valves, and flanges. With a head that's about 10% wider than standard hex head screws, they handle heavier loads by distributing them over a larger area. The head also has six flat sides to keep wrenches and sockets from slipping and rounding off the drive.
Length is measured from under the head.
High-Strength Fastener—Commonly used to fasten components in valves, pumps, motors, and other high-stress applications. These screws have a tensile strength of 125,000 to 160,000 psi.
ASTM Grade L7—In addition to handling high heat, these screws stay strong in freezing temperatures without cracking. They're frequently used in industrial refrigeration systems, cold-storage facilities, and pipelines for oil and gas.
Steel—Unfinished steel screws are best for dry environments, since moisture will cause them to rust. They require little surface prep before applying a finish, so you can apply your own paint or coating.
Grip Length—Screws with a grip length have a precisely measured unthreaded section under the head, called a grip. It's stronger than the threaded section, so you can place it in joints exposed to sideways forces.
Head | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Lg. | Grip Lg. | Wd. | Ht. | Threading | Thread Spacing | Tensile Strength, psi | Specs. Met | Each | |||
High-Strength ASTM Grade L7 Steel | |||||||||||
5/8"-11 | |||||||||||
| 1 1/2" | — | 1 1/16" | 27/64" | Fully Threaded | Coarse | 125,000 | ASME B18.2.1 ASTM A320 ASTM A962 | 97777A101 | 00000 | ||
| 1 3/4" | — | 1 1/16" | 27/64" | Fully Threaded | Coarse | 125,000 | ASME B18.2.1 ASTM A320 ASTM A962 | 97777A102 | 0000 | ||
| 2" | — | 1 1/16" | 27/64" | Fully Threaded | Coarse | 125,000 | ASME B18.2.1 ASTM A320 ASTM A962 | 97777A103 | 0000 | ||
| 2 1/4" | 3/4" | 1 1/16" | 27/64" | Partially Threaded | Coarse | 125,000 | ASME B18.2.1 ASTM A320 ASTM A962 | 97777A104 | 0000 | ||
| 2 1/2" | 1" | 1 1/16" | 27/64" | Partially Threaded | Coarse | 125,000 | ASME B18.2.1 ASTM A320 ASTM A962 | 97777A105 | 0000 | ||
| 2 3/4" | 1 1/4" | 1 1/16" | 27/64" | Partially Threaded | Coarse | 125,000 | ASME B18.2.1 ASTM A320 ASTM A962 | 97777A106 | 0000 | ||
| 3" | 1 1/2" | 1 1/16" | 27/64" | Partially Threaded | Coarse | 125,000 | ASME B18.2.1 ASTM A320 ASTM A962 | 97777A107 | 0000 | ||
| 3 1/4" | 1 3/4" | 1 1/16" | 27/64" | Partially Threaded | Coarse | 125,000 | ASME B18.2.1 ASTM A320 ASTM A962 | 97777A108 | 0000 | ||
| 3 1/2" | 2" | 1 1/16" | 27/64" | Partially Threaded | Coarse | 125,000 | ASME B18.2.1 ASTM A320 ASTM A962 | 97777A109 | 0000 | ||
| 4" | 2 1/2" | 1 1/16" | 27/64" | Partially Threaded | Coarse | 125,000 | ASME B18.2.1 ASTM A320 ASTM A962 | 97777A111 | 0000 | ||
3/4"-10 | |||||||||||
| 2" | — | 1 1/4" | 1/2" | Fully Threaded | Coarse | 125,000 | ASME B18.2.1 ASTM A320 ASTM A962 | 97777A112 | 0000 | ||
| 2 1/4" | — | 1 1/4" | 1/2" | Fully Threaded | Coarse | 125,000 | ASME B18.2.1 ASTM A320 ASTM A962 | 97777A113 | 0000 | ||
| 2 1/2" | 3/4" | 1 1/4" | 1/2" | Partially Threaded | Coarse | 125,000 | ASME B18.2.1 ASTM A320 ASTM A962 | 97777A114 | 0000 | ||
| 2 3/4" | 1" | 1 1/4" | 1/2" | Partially Threaded | Coarse | 125,000 | ASME B18.2.1 ASTM A320 ASTM A962 | 97777A115 | 0000 | ||
| 3" | 1 1/4" | 1 1/4" | 1/2" | Partially Threaded | Coarse | 125,000 | ASME B18.2.1 ASTM A320 ASTM A962 | 97777A116 | 0000 | ||
| 3 1/4" | 1 1/2" | 1 1/4" | 1/2" | Partially Threaded | Coarse | 125,000 | ASME B18.2.1 ASTM A320 ASTM A962 | 97777A117 | 0000 | ||
| 3 1/2" | 1 3/4" | 1 1/4" | 1/2" | Partially Threaded | Coarse | 125,000 | ASME B18.2.1 ASTM A320 ASTM A962 | 97777A118 | 0000 | ||
| 3 3/4" | 2" | 1 1/4" | 1/2" | Partially Threaded | Coarse | 125,000 | ASME B18.2.1 ASTM A320 ASTM A962 | 97777A119 | 0000 | ||
| 4" | 2 1/4" | 1 1/4" | 1/2" | Partially Threaded | Coarse | 125,000 | ASME B18.2.1 ASTM A320 ASTM A962 | 97777A121 | 0000 | ||
| 4 1/4" | 2 1/2" | 1 1/4" | 1/2" | Partially Threaded | Coarse | 125,000 | ASME B18.2.1 ASTM A320 ASTM A962 | 97777A122 | 0000 | ||
| 4 1/2" | 2 3/4" | 1 1/4" | 1/2" | Partially Threaded | Coarse | 125,000 | ASME B18.2.1 ASTM A320 ASTM A962 | 97777A123 | 0000 | ||
| 4 3/4" | 3" | 1 1/4" | 1/2" | Partially Threaded | Coarse | 125,000 | ASME B18.2.1 ASTM A320 ASTM A962 | 97777A124 | 00000 | ||
| 5" | 3 1/4" | 1 1/4" | 1/2" | Partially Threaded | Coarse | 125,000 | ASME B18.2.1 ASTM A320 ASTM A962 | 97777A125 | 00000 | ||
| 5 1/2" | 3 3/4" | 1 1/4" | 1/2" | Partially Threaded | Coarse | 125,000 | ASME B18.2.1 ASTM A320 ASTM A962 | 97777A126 | 00000 | ||
| 6" | 4 1/4" | 1 1/4" | 1/2" | Partially Threaded | Coarse | 125,000 | ASME B18.2.1 ASTM A320 ASTM A962 | 97777A127 | 00000 | ||
7/8"-9 | |||||||||||
| 3" | 1" | 1 7/16" | 37/64" | Partially Threaded | Coarse | 125,000 | ASME B18.2.1 ASTM A320 ASTM A962 | 97777A128 | 00000 | ||
| 3 1/2" | 1 1/2" | 1 7/16" | 37/64" | Partially Threaded | Coarse | 125,000 | ASME B18.2.1 ASTM A320 ASTM A962 | 97777A129 | 00000 | ||
| 4" | 2" | 1 7/16" | 37/64" | Partially Threaded | Coarse | 125,000 | ASME B18.2.1 ASTM A320 ASTM A962 | 97777A131 | 00000 | ||
| 4 1/2" | 2 1/2" | 1 7/16" | 37/64" | Partially Threaded | Coarse | 125,000 | ASME B18.2.1 ASTM A320 ASTM A962 | 97777A132 | 00000 | ||
| 4 3/4" | 2 3/4" | 1 7/16" | 37/64" | Partially Threaded | Coarse | 125,000 | ASME B18.2.1 ASTM A320 ASTM A962 | 97777A133 | 00000 | ||
| 5" | 3" | 1 7/16" | 37/64" | Partially Threaded | Coarse | 125,000 | ASME B18.2.1 ASTM A320 ASTM A962 | 97777A134 | 00000 | ||
1"-8 | |||||||||||
| 3" | 3/4" | 1 5/8" | 43/64" | Partially Threaded | Coarse | 125,000 | ASME B18.2.1 ASTM A320 ASTM A962 | 97777A135 | 00000 | ||
| 3 1/4" | 1" | 1 5/8" | 43/64" | Partially Threaded | Coarse | 125,000 | ASME B18.2.1 ASTM A320 ASTM A962 | 97777A136 | 00000 | ||
| 3 1/2" | 1 1/4" | 1 5/8" | 43/64" | Partially Threaded | Coarse | 125,000 | ASME B18.2.1 ASTM A320 ASTM A962 | 97777A137 | 00000 | ||
| 3 3/4" | 1 1/2" | 1 5/8" | 43/64" | Partially Threaded | Coarse | 125,000 | ASME B18.2.1 ASTM A320 ASTM A962 | 97777A138 | 00000 | ||
| 4" | 1 3/4" | 1 5/8" | 43/64" | Partially Threaded | Coarse | 125,000 | ASME B18.2.1 ASTM A320 ASTM A962 | 97777A139 | 00000 | ||
| 4 1/2" | 2 1/4" | 1 5/8" | 43/64" | Partially Threaded | Coarse | 125,000 | ASME B18.2.1 ASTM A320 ASTM A962 | 97777A141 | 00000 | ||
| 5" | 2 3/4" | 1 5/8" | 43/64" | Partially Threaded | Coarse | 125,000 | ASME B18.2.1 ASTM A320 ASTM A962 | 97777A142 | 00000 | ||
| 5 1/2" | 3 1/4" | 1 5/8" | 43/64" | Partially Threaded | Coarse | 125,000 | ASME B18.2.1 ASTM A320 ASTM A962 | 97777A143 | 00000 | ||
| 6" | 3 3/4" | 1 5/8" | 43/64" | Partially Threaded | Coarse | 125,000 | ASME B18.2.1 ASTM A320 ASTM A962 | 97777A144 | 00000 | ||
Steel Heavy Hex Head Screw Kits for Metal Pipe Flanges
 |  |
Shown Installed |
All the hardware you need to join steel or cast iron pipe flanges. These kits come with screws and nuts in the right size and number to match your flange's bolt holes. With screw heads and nuts that are about 10% wider than standard, these kits handle heavier loads by distributing them over a larger area. The head also gives you six, flat contact points, so wrenches and sockets won't slip and round off the drive.
Screw length is measured from under the head. For a tight seal, you’ll also need a gasket between the flanges.
ASTM Grade L7—In addition to handling high heat, these screws stay strong in freezing temperatures without cracking. They're frequently used in industrial refrigeration systems, cold-storage facilities, and pipelines for oil and gas.
Steel—Unfinished steel screws are best for dry environments, since moisture will cause them to rust. They require little surface prep before applying a finish, so you can apply your own paint or coating.
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Certificates with a traceable lot number are available for these products. Download certificates from ORDER HISTORY after your order ships.
Screw | Nut | Steel Screws and Nuts | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
For Pipe Size | Thread Size | Lg. | Head Wd. | Head Ht. | Threading | Thread Spacing | Tensile Strength, psi | Wd. | Ht. | Includes | Each | |||
ASTM Grade L7 for Class 125/150 Flanges | ||||||||||||||
| 1, 1 1/4 | 1/2"-13 | 2 1/4" | 7/8" | 11/32" | Partially Threaded | Coarse | 125,000 | 7/8" | 31/64" | 4 Heavy Hex Head Screws 4 Heavy Hex Nuts | 97771A128 | 000000 | ||
| 1 1/2 | 1/2"-13 | 2 1/2" | 7/8" | 11/32" | Partially Threaded | Coarse | 125,000 | 7/8" | 31/64" | 4 Heavy Hex Head Screws 4 Heavy Hex Nuts | 97771A129 | 00000 | ||
| 2 | 5/8"-11 | 2 3/4" | 1 1/16" | 27/64" | Partially Threaded | Coarse | 125,000 | 1 1/16" | 39/64" | 4 Heavy Hex Head Screws 4 Heavy Hex Nuts | 97771A131 | 00000 | ||
| 2 1/2, 3 | 5/8"-11 | 3" | 1 1/16" | 27/64" | Partially Threaded | Coarse | 125,000 | 1 1/16" | 39/64" | 4 Heavy Hex Head Screws 4 Heavy Hex Nuts | 97771A132 | 00000 | ||
| 3 1/2, 4 | 5/8"-11 | 3" | 1 1/16" | 27/64" | Partially Threaded | Coarse | 125,000 | 1 1/16" | 39/64" | 8 Heavy Hex Head Screws 8 Heavy Hex Nuts | 97771A133 | 00000 | ||
| 5, 6 | 3/4"-10 | 3 1/4" | 1 1/4" | 1/2" | Partially Threaded | Coarse | 125,000 | 1 1/4" | 47/64" | 8 Heavy Hex Head Screws 8 Heavy Hex Nuts | 97771A134 | 00000 | ||
