Drive Style Drive Style | Show |
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Drive Style Drive Style | Hide |
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System of Measurement System of Measurement |
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Material Material |
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Finish Finish |
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Head Type Head Type |
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![]() | Rounded |
Rounded Head Style Rounded Head Style |
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Threading Threading |
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Thread Direction Thread Direction |
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Thread Fit Thread Fit |
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Tensile Strength Tensile Strength |
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Rounded Head Profile Rounded Head Profile |
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RoHS (Restriction of Hazardous Substances) RoHS (Restriction ofHazardous Substances) |
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Specifications Met Specifications Met |
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DFARS (Defense Acquisition Regulations Supplement) DFARS (Defense AcquisitionRegulations Supplement) |
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REACH (Registration, Evaluation, Authorization and Restriction of Chemicals) REACH (Registration,Evaluation, Authorization and Restriction of Chemicals) |
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About Rounded Head Screws
More
Stainless Steel Tamper-Resistant One-Way Round Head Screws

Made from 18-8 stainless steel, these screws have good chemical resistance and may be mildly magnetic. They’re passivated for added protection against oxidation and corrosion. The S-shaped drive can be installed with a standard slotted driver, but requires a special tool for removal (sold separately). For removal tools, see one-way bits and drivers. Length is measured from under the head.
For technical drawings and 3-D models, click on a part number.
| Lg. | Threading | Head Dia. | Head Ht. | Tensile Strength, psi | Specifications Met | Pkg. Qty. | Pkg. | |
18-8 Stainless Steel | ||||||||
|---|---|---|---|---|---|---|---|---|
4-40 | ||||||||
| 3/16" | Fully Threaded | 0.211" | 0.086" | 80,000 | __ | 100 | 000000000 | 000000 |
| 1/4" | Fully Threaded | 0.211" | 0.086" | 80,000 | __ | 100 | 000000000 | 00000 |
| 3/8" | Fully Threaded | 0.211" | 0.086" | 80,000 | ASME B18.6.3 | 100 | 000000000 | 00000 |
| 1/2" | Fully Threaded | 0.211" | 0.086" | 80,000 | ASME B18.6.3 | 100 | 000000000 | 00000 |
| 3/4" | Fully Threaded | 0.211" | 0.086" | 80,000 | __ | 100 | 000000000 | 00000 |
6-32 | ||||||||
| 3/16" | Fully Threaded | 0.260" | 0.103" | 80,000 | ASME B18.6.3 | 100 | 000000000 | 00000 |
| 1/4" | Fully Threaded | 0.260" | 0.103" | 80,000 | ASME B18.6.3 | 100 | 000000000 | 00000 |
| 3/8" | Fully Threaded | 0.260" | 0.103" | 80,000 | ASME B18.6.3 | 100 | 000000000 | 00000 |
| 1/2" | Fully Threaded | 0.260" | 0.103" | 80,000 | ASME B18.6.3 | 100 | 000000000 | 00000 |
| 3/4" | Fully Threaded | 0.260" | 0.103" | 80,000 | ASME B18.6.3 | 100 | 000000000 | 00000 |
| 1" | Fully Threaded | 0.260" | 0.103" | 80,000 | ASME B18.6.3 | 50 | 000000000 | 00000 |
| 1 1/2" | Fully Threaded | 0.260" | 0.103" | 80,000 | ASME B18.6.3 | 50 | 000000000 | 00000 |
8-32 | ||||||||
| 1/4" | Fully Threaded | 0.309" | 0.120" | 80,000 | ASME B18.6.3 | 50 | 000000000 | 00000 |
| 3/8" | Fully Threaded | 0.309" | 0.120" | 80,000 | ASME B18.6.3 | 50 | 000000000 | 00000 |
| 1/2" | Fully Threaded | 0.309" | 0.120" | 80,000 | ASME B18.6.3 | 50 | 000000000 | 00000 |
| 3/4" | Fully Threaded | 0.309" | 0.120" | 80,000 | ASME B18.6.3 | 50 | 000000000 | 00000 |
| 1" | Fully Threaded | 0.309" | 0.120" | 80,000 | ASME B18.6.3 | 50 | 000000000 | 00000 |
| 1 1/2" | Fully Threaded | 0.309" | 0.120" | 80,000 | ASME B18.6.3 | 50 | 000000000 | 00000 |
10-24 | ||||||||
| 1/2" | Fully Threaded | 0.359" | 0.137" | 80,000 | ASME B18.6.3 | 50 | 000000000 | 00000 |
| 3/4" | Fully Threaded | 0.359" | 0.137" | 80,000 | ASME B18.6.3 | 50 | 000000000 | 00000 |
| 1" | Fully Threaded | 0.359" | 0.137" | 80,000 | ASME B18.6.3 | 50 | 000000000 | 00000 |
| 1 1/4" | Fully Threaded | 0.359" | 0.137" | 80,000 | ASME B18.6.3 | 50 | 000000000 | 00000 |
| 1 1/2" | Fully Threaded | 0.359" | 0.137" | 80,000 | ASME B18.6.3 | 25 | 000000000 | 00000 |
10-32 | ||||||||
| 1/4" | Fully Threaded | 0.359" | 0.137" | 80,000 | __ | 50 | 000000000 | 00000 |
| 3/8" | Fully Threaded | 0.359" | 0.137" | 80,000 | __ | 50 | 000000000 | 00000 |
| 1/2" | Fully Threaded | 0.359" | 0.137" | 80,000 | ASME B18.6.3 | 50 | 000000000 | 00000 |
| 5/8" | Fully Threaded | 0.359" | 0.137" | 80,000 | ASME B18.6.3 | 50 | 000000000 | 00000 |
| 3/4" | Fully Threaded | 0.359" | 0.137" | 80,000 | ASME B18.6.3 | 50 | 000000000 | 00000 |
| 1" | Fully Threaded | 0.359" | 0.137" | 80,000 | ASME B18.6.3 | 50 | 000000000 | 00000 |
| 1 1/4" | Fully Threaded | 0.359" | 0.137" | 80,000 | ASME B18.6.3 | 25 | 000000000 | 00000 |
| 1 1/2" | Fully Threaded | 0.359" | 0.137" | 80,000 | ASME B18.6.3 | 25 | 000000000 | 00000 |
1/4"-20 | ||||||||
| 3/8" | Fully Threaded | 0.472" | 0.175" | 80,000 | __ | 25 | 000000000 | 00000 |
| 1/2" | Fully Threaded | 0.472" | 0.175" | 80,000 | __ | 25 | 000000000 | 0000 |
| 3/4" | Fully Threaded | 0.472" | 0.175" | 80,000 | __ | 25 | 000000000 | 00000 |
| 1" | Fully Threaded | 0.472" | 0.175" | 80,000 | __ | 25 | 000000000 | 00000 |
| 1 1/2" | Fully Threaded | 0.472" | 0.175" | 80,000 | __ | 25 | 000000000 | 00000 |
| 2" | Fully Threaded | 0.472" | 0.175" | 80,000 | ASME B18.6.3 | 10 | 000000000 | 00000 |
Steel Tamper-Resistant One-Way Round Head Screws

The S-shaped drive can be installed with a standard slotted driver, but requires a special tool for removal (sold separately). For removal tools, see one-way bits and drivers. Screws have a zinc plating for corrosion resistance in wet environments. Length is measured from under the head.
For technical drawings and 3-D models, click on a part number.
| Lg. | Threading | Head Dia. | Head Ht. | Tensile Strength, psi | Specifications Met | Pkg. Qty. | Pkg. | |
Zinc-Plated Steel | ||||||||
|---|---|---|---|---|---|---|---|---|
4-40 | ||||||||
| 1/4" | Fully Threaded | 0.211" | 0.086" | 60,000 | __ | 100 | 000000000 | 000000 |
| 3/8" | Fully Threaded | 0.211" | 0.086" | 60,000 | __ | 100 | 000000000 | 00000 |
| 1/2" | Fully Threaded | 0.211" | 0.086" | 60,000 | __ | 100 | 000000000 | 00000 |
| 3/4" | Fully Threaded | 0.211" | 0.086" | 60,000 | __ | 100 | 000000000 | 00000 |
6-32 | ||||||||
| 1/4" | Fully Threaded | 0.260" | 0.103" | 60,000 | __ | 100 | 000000000 | 00000 |
| 3/8" | Fully Threaded | 0.260" | 0.103" | 60,000 | ASME B18.6.3 | 100 | 000000000 | 00000 |
| 1/2" | Fully Threaded | 0.260" | 0.103" | 60,000 | ASME B18.6.3 | 100 | 000000000 | 00000 |
| 3/4" | Fully Threaded | 0.260" | 0.103" | 60,000 | ASME B18.6.3 | 100 | 000000000 | 00000 |
| 1" | Fully Threaded | 0.260" | 0.103" | 60,000 | ASME B18.6.3 | 100 | 000000000 | 00000 |
8-32 | ||||||||
| 1/4" | Fully Threaded | 0.309" | 0.120" | 60,000 | __ | 100 | 000000000 | 00000 |
| 3/8" | Fully Threaded | 0.309" | 0.120" | 60,000 | __ | 100 | 000000000 | 00000 |
| 1/2" | Fully Threaded | 0.309" | 0.120" | 60,000 | ASME B18.6.3 | 100 | 000000000 | 00000 |
| 3/4" | Fully Threaded | 0.309" | 0.120" | 60,000 | ASME B18.6.3 | 100 | 000000000 | 00000 |
| 1" | Fully Threaded | 0.309" | 0.120" | 60,000 | ASME B18.6.3 | 100 | 000000000 | 00000 |
| 1 1/2" | Fully Threaded | 0.309" | 0.120" | 60,000 | ASME B18.6.3 | 100 | 000000000 | 00000 |
10-24 | ||||||||
| 1/2" | Fully Threaded | 0.359" | 0.137" | 60,000 | ASME B18.6.3 | 100 | 000000000 | 00000 |
| 3/4" | Fully Threaded | 0.359" | 0.137" | 60,000 | ASME B18.6.3 | 100 | 000000000 | 00000 |
| 1" | Fully Threaded | 0.359" | 0.137" | 60,000 | ASME B18.6.3 | 100 | 000000000 | 00000 |
| 1 1/2" | Fully Threaded | 0.359" | 0.137" | 60,000 | ASME B18.6.3 | 50 | 000000000 | 00000 |
10-32 | ||||||||
| 1/4" | Fully Threaded | 0.359" | 0.137" | 60,000 | __ | 100 | 000000000 | 00000 |
| 3/8" | Fully Threaded | 0.359" | 0.137" | 60,000 | __ | 100 | 000000000 | 00000 |
| 1/2" | Fully Threaded | 0.359" | 0.137" | 60,000 | ASME B18.6.3 | 100 | 000000000 | 00000 |
| 3/4" | Fully Threaded | 0.359" | 0.137" | 60,000 | ASME B18.6.3 | 100 | 000000000 | 00000 |
| 1" | Fully Threaded | 0.359" | 0.137" | 60,000 | ASME B18.6.3 | 100 | 000000000 | 00000 |
| 1 1/2" | Fully Threaded | 0.359" | 0.137" | 60,000 | ASME B18.6.3 | 50 | 000000000 | 00000 |
1/4"-20 | ||||||||
| 3/8" | Fully Threaded | 0.472" | 0.175" | 60,000 | __ | 50 | 000000000 | 00000 |
| 1/2" | Fully Threaded | 0.472" | 0.175" | 60,000 | ASME B18.6.3 | 50 | 000000000 | 00000 |
| 3/4" | Fully Threaded | 0.472" | 0.175" | 60,000 | ASME B18.6.3 | 50 | 000000000 | 00000 |
| 1" | Fully Threaded | 0.472" | 0.175" | 60,000 | ASME B18.6.3 | 50 | 000000000 | 00000 |
| 1 1/2" | Fully Threaded | 0.472" | 0.175" | 60,000 | ASME B18.6.3 | 50 | 000000000 | 00000 |





























