Product Specifications
| Model / Specification | M2-M10 |
| Material | Carbon steel, Stainless steel |
| Thread size d | M2 | (M2.5) | M3 | (M3.5) | M4 | M5 | M6 | M8 | M10 | ||
|---|---|---|---|---|---|---|---|---|---|---|---|
| P | Pitch | 0.4 | 0.45 | 0.5 | 0.6 | 0.7 | 0.8 | 1 | 1.25 | 1.5 | |
| a | Max. | 0.8 | 0.9 | 1 | 1.2 | 1.4 | 2 | 2.5 | 3.13 | 3.75 | |
| b | Ref. | 25 | 25 | 25 | 38 | 38 | 38 | 38 | 38 | 38 | |
| dk | Theoretical | Max. | 4.4 | 5.5 | 6.3 | 8.2 | 9.4 | 10.4 | 12.6 | 17.3 | 20 |
| Actual | Max. | 3.8 | 4.7 | 5.5 | 7.3 | 8.4 | 9.3 | 11.3 | 15.8 | 18.3 | |
| Min. | 3.5 | 4.4 | 5.2 | 6.94 | 8.04 | 8.94 | 10.87 | 15.37 | 17.78 | ||
| ds | ≈ | 1.7 | 2.15 | 2.6 | 3.05 | 3.5 | 4.4 | 5.3 | 7.1 | 8.9 | |
| k | Max.=nominal | 1.2 | 1.5 | 1.65 | 2.35 | 2.7 | 2.7 | 3.3 | 4.65 | 5 | |
| Min. | 0.985 | 1.224 | 1.369 | 1.995 | 2.333 | 2.28 | 2.81 | 4.06 | 4.4 | ||
| r | Max. | 0.5 | 0.6 | 0.8 | 0.9 | 1 | 1.3 | 1.5 | 2 | 2.5 | |
| Min. | 0.1 | 0.1 | 0.1 | 0.15 | 0.2 | 0.2 | 0.25 | 0.4 | 0.4 | ||
| x | Max. | 1 | 1.1 | 1.25 | 1.5 | 1.75 | 2 | 2.5 | 3.2 | 3.8 | |
| Socket | T6 | T8 | T10 | T15 | T20 | T25 | T30 | T45 | T50 | ||
| A | Ref. | 1.75 | 2.4 | 2.8 | 3.35 | 3.95 | 4.5 | 5.6 | 7.95 | 8.95 | |
| t | Max. | 0.64 | 0.79 | 0.83 | 1.32 | 1.53 | 1.51 | 1.78 | 2.54 | 2.8 | |
| Min. | 0.51 | 0.66 | 0.7 | 1.16 | 1.14 | 1.12 | 1.39 | 2.15 | 2.41 | ||
| Min. tensile load (N) | 4.8 | 700 | 1140 | 1700 | 2280 | 2950 | 4770 | 6770 | 12300 | 19500 | |
| 8.8 | 1330 | 2180 | 3220 | 4340 | 5620 | 9120 | 12900 | 23400 | 37100 | ||
| 10.9 | 1730 | 2820 | 4190 | 5640 | 7300 | 11800 | 16800 | 30500 | 48300 | ||
| 50 | 830 | 1360 | 2020 | 2710 | 3510 | 5680 | 8080 | 14700 | 23200 | ||
| 70 | 1170 | 1900 | 2820 | 3800 | 4920 | 7940 | 11300 | 20600 | 32500 | ||
| Weight ≈ kg / 1000 pcs | - | - | - | - | - | - | - | - | - | ||
| Thread length b | - | - | - | - | - | - | - | - | - | ||
Dimensions in mm. The bracketed sizes (M2.5, M3.5) are non-preferred. Data compiled from GB/T 2673.1-2025 for selection reference only; actual supply is subject to drawings and inspection reports.
Product Overview
The hexalobular socket countersunk head screw, also known as a Torx countersunk screw, is manufactured to GB/T 2673.1-2025. Its 90 degree countersunk head sits flush with the workpiece surface after tightening, making it suitable where the screw head must not protrude. The drive is a hexalobular (six-lobe / Torx) socket with rounded load flanks that spread the tightening torque evenly, reduce cam-out and make the screw well suited to automated assembly lines.
1. Product Features
- 90 degree countersunk head: sits flush with the workpiece surface after assembly for a flat, snag-free finish.
- Hexalobular (Torx) socket drive: six rounded lobes transmit torque evenly, resist cam-out and protect the recess.
- Thread sizes from M2 to M10, covering a wide range of applications.
- Available in carbon steel and stainless steel, selected according to environment and strength requirements.
- Head angle and head dimensions are controlled to the standard to ensure a proper fit in the countersink.
2. Product Advantages
- Compared with a cross recess or a plain hex socket, the hexalobular recess together with a dedicated Torx driver allows higher tightening torque and reduces stripping and rejects during assembly.
- The countersunk design keeps the assembled surface flat, which suits visible surfaces and areas where interference must be avoided.
- High degree of standardisation: the GB/T 2673.1 dimensional system is complete, which simplifies export matching and second sourcing.
- Material and surface finish can be customised to balance strength, corrosion resistance and cost.
3. Application Scope
- Assembly of structural parts in electronics, instruments and office equipment where surface flatness matters.
- Automotive interiors, rail transit and general machinery where countersunk installation is required.
- Stainless steel versions suit damp or mildly corrosive environments, as well as food and medical equipment.
- Automated assembly lines and robotic tightening stations that require high recess fit accuracy.
