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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 |
Tri-Groove Sockets
Square Drive
Hex Drive
Grip the indentations around the outside of tri-groove fasteners. These sockets are for hand-driven use only.
Hex-drive sockets are specialty sockets that require the use of another 1" socket when used with a ratchet wrench.
| Drive Size | Overall Lg. | OD | For Fastener Type | For Screw Size (Head Dia.) | For Nut Size (Dia.) | Material | Each | |
1/4" Square Drive | ||||||||
|---|---|---|---|---|---|---|---|---|
| No. 4 | 1" | 31/64" | Screws | No. 4 Standard (0.13") No. 6 Countersunk (0.268") | __ | Black-Oxide Steel | 0000000 | 000000 |
| No. 6 | 1" | 31/64" | Screws | No. 6, No. 8 Standard (0.208") No. 8, No. 10 Countersunk (0.372") | __ | Black-Oxide Steel | 0000000 | 00000 |
| No. 10 | 1" | 31/64" | Screws and Nuts | 1/4", No. 10, No. 12 Standard (0.334") 1/4" Countersunk (0.492") | No. 6, No. 8 (0.406") | Black-Oxide Steel | 0000000 | 00000 |
3/8" Square Drive | ||||||||
| No. 20 | 1" | 47/64" | Screws and Nuts | 5/16" Standard (0.585") | 1/4", No. 10 (0.661") | Black-Oxide Steel | 0000000 | 00000 |
| No. 30 | 1 1/4" | 31/32" | Nuts | __ | 3/8", 5/16" (0.864") | Black-Oxide Steel | 0000000 | 00000 |
| No. 40 | 1 1/4" | 31/32" | Nuts | __ | 1/2" (0.93") | Black-Oxide Steel | 00000000 | 00000 |
1/2" Square Drive | ||||||||
| 1/2" | 1 1/4" | 1 1/4" | Nuts | __ | 1/2", M12, M14 (12mm, 0.5", 14mm) | Steel | 0000000 | 00000 |
1" Hex Drive | ||||||||
| 1" | 2" | 1 5/8" | Nuts | __ | M16, M20 (0.625", 16mm, 18mm, 0.75", 20mm) | Black-Oxide Steel | 0000000 | 000000 |
Tri-Groove Socket Sets
Grip the indentations around the outside of tri-groove fasteners.
| No. of Pieces | Components Included | Includes | Finish | Each | |
1/4" Square Drive—Steel | |||||
|---|---|---|---|---|---|
| 4 | 3 Sockets 1 Drive Tool | Standard Socket: No. 4 (For No. 4 Standard Screws and No. 6 Countersunk Screws) Standard Socket: No. 6 (For Nos. 6 and 8 Standard Screws and Nos. 8 and 10 Countersunk Screws) Standard Socket: No. 10 (For Nos. 10, 12, and 1/4" Standard Screws; 1/4" Countersunk Screws; and Nos. 6 and 8 Nuts) 8" Long Socket Screwdiver Handle | Black Oxide | 0000000 | 000000 |