About Rounded Head Screws
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Tamper-Resistant Tri-Groove Rounded Head Screws
Difficult to remove without special tools, these screws have three grooves. For installation tools, see Tri-Groove bits and drivers. Screws are zinc plated 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 | Min. Thread Lg. | Head Dia. | Head Ht. | Drive Size | Tensile Strength, psi  | Pkg. Qty. | Pkg. | |
Zinc-Plated Steel | |||||||||
|---|---|---|---|---|---|---|---|---|---|
6-32 | |||||||||
| 3/8" | Fully Threaded | __ | 0.26" | 0.12" | No. 6 | 80,000 | 50 | 000000000 | 000000 |
| 1/2" | Fully Threaded | __ | 0.26" | 0.12" | No. 6 | 80,000 | 50 | 000000000 | 00000 |
| 3/4" | Fully Threaded | __ | 0.26" | 0.12" | No. 6 | 80,000 | 50 | 000000000 | 00000 |
8-32 | |||||||||
| 3/8" | Fully Threaded | __ | 0.28" | 0.148" | No. 6 | 80,000 | 50 | 000000000 | 00000 |
| 1/2" | Fully Threaded | __ | 0.28" | 0.148" | No. 6 | 80,000 | 50 | 000000000 | 00000 |
| 3/4" | Fully Threaded | __ | 0.28" | 0.148" | No. 6 | 80,000 | 50 | 000000000 | 00000 |
| 1" | Fully Threaded | __ | 0.28" | 0.148" | No. 6 | 80,000 | 50 | 000000000 | 00000 |
| 1 1/4" | Fully Threaded | __ | 0.28" | 0.148" | No. 6 | 80,000 | 50 | 000000000 | 00000 |
| 1 1/2" | Fully Threaded | __ | 0.28" | 0.148" | No. 6 | 80,000 | 50 | 000000000 | 00000 |
10-24 | |||||||||
| 1/2" | Fully Threaded | __ | 0.375" | 0.15" | No. 10 | 80,000 | 50 | 000000000 | 00000 |
| 3/4" | Fully Threaded | __ | 0.375" | 0.15" | No. 10 | 80,000 | 50 | 000000000 | 00000 |
| 1" | Fully Threaded | __ | 0.375" | 0.15" | No. 10 | 80,000 | 25 | 000000000 | 0000 |
| 1 1/2" | Fully Threaded | __ | 0.375" | 0.15" | No. 10 | 80,000 | 25 | 000000000 | 0000 |
10-32 | |||||||||
| 1/2" | Fully Threaded | __ | 0.375" | 0.15" | No. 10 | 80,000 | 50 | 000000000 | 00000 |
| 3/4" | Fully Threaded | __ | 0.375" | 0.15" | No. 10 | 80,000 | 50 | 000000000 | 00000 |
| 1" | Fully Threaded | __ | 0.375" | 0.15" | No. 10 | 80,000 | 50 | 000000000 | 00000 |
| 1 1/2" | Fully Threaded | __ | 0.375" | 0.15" | No. 10 | 80,000 | 25 | 000000000 | 0000 |
1/4"-20 | |||||||||
| 1/2" | Fully Threaded | __ | 0.375" | 0.155" | No. 10 | 80,000 | 50 | 000000000 | 00000 |
| 3/4" | Fully Threaded | __ | 0.375" | 0.155" | No. 10 | 80,000 | 50 | 000000000 | 00000 |
| 1" | Fully Threaded | __ | 0.375" | 0.155" | No. 10 | 80,000 | 25 | 000000000 | 0000 |
| 1 1/2" | Fully Threaded | __ | 0.375" | 0.155" | No. 10 | 80,000 | 25 | 000000000 | 0000 |
| 2" | Fully Threaded | __ | 0.375" | 0.155" | No. 10 | 80,000 | 25 | 000000000 | 00000 |
| 2 1/2" | Partially Threaded | 1 1/2" | 0.375" | 0.155" | No. 10 | 80,000 | 10 | 000000000 | 0000 |
5/16"-18 | |||||||||
| 5/8" | Fully Threaded | __ | 0.57" | 0.275" | No. 20 | 80,000 | 25 | 000000000 | 00000 |
| 3/4" | Fully Threaded | __ | 0.57" | 0.275" | No. 20 | 80,000 | 25 | 000000000 | 00000 |
| 1" | Fully Threaded | __ | 0.57" | 0.275" | No. 20 | 80,000 | 25 | 000000000 | 00000 |