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Choose a hex head fastener with the right threading, thread size, material, and strength for your equipment.
About Nuts, Materials, and Finishes
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18-8 Stainless Steel Heavy Hex Head Screws for High-Pressure Applications
Made of 18-8 stainless steel, these Grade B8 screws resist corrosion from mild chemicals and water. They may be mildly magnetic. Also known as pressure bolts, these screws meet the high-pressure and high-temperature regulations of ASTM A193. They’re often used to secure pressure tanks, valves, and flanges. Length is measured from under the head. Use these screws with ASTM A194 Grade 8 nuts (sold separately).
Partially threaded screws 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 subjected to sideways force.
Screws | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Head | Nuts | ||||||||||||
| Lg. | Threading | Thread Spacing  | Thread Lg. | Grip Lg. | Wd. | Ht. | Tensile Strength, psi | Specifications Met | Each | Pkg. Qty. | Pkg. | ||
ASTM Grade B8 18-8 Stainless Steel | |||||||||||||
1 1/8"-8 | |||||||||||||
| 3" | Fully Threaded | Coarse | __ | __ | 1 13/16" | 3/4" | 75,000 | ASTM A193, ASTM A962 | 92655A122 | 000000 | 1 | 94252A732 | 00000 |
| 3 1/2" | Fully Threaded | Coarse | __ | __ | 1 13/16" | 3/4" | 75,000 | ASTM A193, ASTM A962 | 92655A121 | 00000 | 1 | 94252A732 | 0000 |
| 4" | Partially Threaded | Coarse | 2 1/2" | 1 1/2" | 1 13/16" | 3/4" | 75,000 | ASTM A193, ASTM A962 | 92655A123 | 00000 | 1 | 94252A732 | 0000 |
| 5 3/4" | Partially Threaded | Coarse | 2 1/2" | 3 1/4" | 1 13/16" | 3/4" | 75,000 | ASTM A193, ASTM A962 | 92655A127 | 00000 | 1 | 94252A732 | 0000 |
Super-Corrosion-Resistant 316 Stainless Steel Heavy
Hex Head Screws for High-Pressure Applications
Made from 316 stainless steel, these Grade B8M screws are more corrosion resistant than 18-8 stainless steel screws. They have excellent resistance to chemicals and salt water, and they may be mildly magnetic. Also known as pressure bolts, these screws meet the high-pressure and high-temperature regulations of ASTM A193. They’re often used to secure pressure tanks, valves, and flanges. Length is measured from under the head. Use these screws with Grade 8M nuts.
Partially threaded screws 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 subjected to sideways force.
Fine threads are closely spaced to prevent loosening from vibration.
Screws | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Head | Nuts | ||||||||||||
| Lg. | Threading | Thread Spacing | Thread Lg. | Grip Lg. | Wd. | Ht. | Tensile Strength, psi | Specifications Met | Each | Pkg. Qty. | Pkg. | ||
ASTM Grade B8M 316 Stainless Steel | |||||||||||||
1 1/8"-8 | |||||||||||||
| 2 1/2" | Fully Threaded | Fine | __ | __ | 1 13/16" | 11/16" | 75,000 | ASTM A193, ASTM A962 | 92790A107 | 0000000 | 1 | 97619A920 | 000000 |
| 3" | Fully Threaded | Fine | __ | __ | 1 13/16" | 11/16" | 75,000 | ASTM A193, ASTM A962 | 92790A109 | 000000 | 1 | 97619A920 | 00000 |
| 3 1/2" | Fully Threaded | Fine | __ | __ | 1 13/16" | 11/16" | 75,000 | ASTM A193, ASTM A962 | 92790A108 | 000000 | 1 | 97619A920 | 00000 |
| 4" | Partially Threaded | Fine | 2 1/2" | 1 1/2" | 1 13/16" | 11/16" | 75,000 | ASTM A193, ASTM A962 | 92790A111 | 000000 | 1 | 97619A920 | 00000 |
| 6" | Partially Threaded | Fine | 2 1/2" | 3 1/2" | 1 13/16" | 11/16" | 75,000 | ASTM A193, ASTM A962 | 92790A112 | 000000 | 1 | 97619A920 | 00000 |
Steel Heavy Hex Head Screws for High-Pressure Applications
Made of Grade B7 steel, these screws are nearly twice as strong as Grade B8 and Grade B8M stainless steel screws. Also known as pressure bolts, they meet the high-pressure and high-temperature regulations of ASTM A193 and are used to secure pressure tanks, valves, and flanges. The head is 10% wider than a standard hex head, so it spreads force over a larger area, and you can tighten these screws with more torque. 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. Length is measured from under the head. Use these screws with ASTM A194 nuts and ASTM F436 washers.
All screws meet ASME B18.2.1, which means they’re made to strict dimensional standards.
Partially threaded screws 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 force.
Match the thread spacing of mating components. Fine threads are closely spaced to prevent loosening from vibration.
Screws | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Head | Nuts | ||||||||||||
| Lg. | Threading | Thread Spacing | Thread Lg. | Grip Lg. | Wd. | Ht. | Tensile Strength, psi | Specifications Met | Each | Pkg. Qty. | Pkg. | ||
ASTM Grade B7 Steel | |||||||||||||
1 1/8"-8 | |||||||||||||
| 2 1/2" | Fully Threaded | Fine | __ | __ | 1 13/16" | 11/16" | 125,000 | ASME B18.2.1, ASTM A193, ASTM A962 | 94705A797 | 000000 | 1 | 90521A265 | 00000 |
| 2 3/4" | Fully Threaded | Fine | __ | __ | 1 13/16" | 11/16" | 125,000 | ASME B18.2.1, ASTM A193, ASTM A962 | 94705A798 | 00000 | 1 | 90521A265 | 0000 |
| 3" | Fully Threaded | Fine | __ | __ | 1 13/16" | 11/16" | 125,000 | ASME B18.2.1, ASTM A193, ASTM A962 | 94705A799 | 00000 | 1 | 90521A265 | 0000 |
| 3 1/4" | Fully Threaded | Fine | __ | __ | 1 13/16" | 11/16" | 125,000 | ASME B18.2.1, ASTM A193, ASTM A962 | 94705A811 | 00000 | 1 | 90521A265 | 0000 |
| 3 1/2" | Fully Threaded | Fine | __ | __ | 1 13/16" | 11/16" | 125,000 | ASME B18.2.1, ASTM A193, ASTM A962 | 94705A812 | 00000 | 1 | 90521A265 | 0000 |
| 4" | Partially Threaded | Fine | 2 1/2" | 1 1/2" | 1 13/16" | 11/16" | 125,000 | ASME B18.2.1, ASTM A193, ASTM A962 | 94705A814 | 00000 | 1 | 90521A265 | 0000 |
| 4 1/4" | Partially Threaded | Fine | 2 1/2" | 1 3/4" | 1 13/16" | 11/16" | 125,000 | ASME B18.2.1, ASTM A193, ASTM A962 | 94705A815 | 00000 | 1 | 90521A265 | 0000 |
| 4 1/2" | Partially Threaded | Fine | 2 1/2" | 2" | 1 13/16" | 11/16" | 125,000 | ASME B18.2.1, ASTM A193, ASTM A962 | 94705A816 | 00000 | 1 | 90521A265 | 0000 |
| 4 3/4" | Partially Threaded | Fine | 2 1/2" | 2 1/4" | 1 13/16" | 11/16" | 125,000 | ASME B18.2.1, ASTM A193, ASTM A962 | 94705A817 | 00000 | 1 | 90521A265 | 0000 |
| 5" | Partially Threaded | Fine | 2 1/2" | 2 1/2" | 1 13/16" | 11/16" | 125,000 | ASME B18.2.1, ASTM A193, ASTM A962 | 94705A818 | 00000 | 1 | 90521A265 | 0000 |
| 5 1/2" | Partially Threaded | Fine | 2 1/2" | 3" | 1 13/16" | 11/16" | 125,000 | ASME B18.2.1, ASTM A193, ASTM A962 | 94705A821 | 00000 | 1 | 90521A265 | 0000 |
| 6" | Partially Threaded | Fine | 2 1/2" | 3 1/2" | 1 13/16" | 11/16" | 125,000 | ASME B18.2.1, ASTM A193, ASTM A962 | 94705A823 | 00000 | 1 | 90521A265 | 0000 |
| 6 1/2" | Partially Threaded | Fine | 2 3/4" | 3 3/4" | 1 13/16" | 11/16" | 125,000 | ASME B18.2.1, ASTM A193, ASTM A962 | 94705A825 | 00000 | 1 | 90521A265 | 0000 |
| 7" | Partially Threaded | Fine | 2 3/4" | 4 1/4" | 1 13/16" | 11/16" | 125,000 | ASME B18.2.1, ASTM A193, ASTM A962 | 94705A826 | 00000 | 1 | 90521A265 | 0000 |
| 8" | Partially Threaded | Fine | 2 3/4" | 5 1/4" | 1 13/16" | 11/16" | 125,000 | ASME B18.2.1, ASTM A193, ASTM A962 | 94705A828 | 00000 | 1 | 90521A265 | 0000 |