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Grade 8.8 Spec Table
Grade 8.8 KS Specifications — 21 sizes
ISO 898-1
ISOGrade 8.8
21 sizes| Nominal | Stress Area Aₛ (mm²) | Preload Fₚ (kN) | Dry Torque (Nm) | Lube Torque (Nm) | Wrench |
|---|---|---|---|---|---|
| M3 | 5.03 | 2.25 | 1.35 | 1.01 | 5.5mm |
| M4 | 8.78 | 3.93 | 3.15 | 2.36 | 7mm |
| M5 | 14.2 | 6.36 | 6.36 | 4.77 | 8mm |
| M6 | 20.1 | 9 | 10.8 | 8.1 | 10mm |
| M8 | 36.6 | 16.4 | 26.2 | 19.7 | 13mm |
| M10 | 58 | 26 | 52 | 39 | 17mm |
| M12 | 84.3 | 37.8 | 90.6 | 68 | 19mm |
| M14 | 115 | 51.5 | 144 | 108 | 22mm |
| M16 | 157 | 70.3 | 225 | 169 | 24mm |
| M18 | 192 | 86 | 310 | 232 | 27mm |
| M20 | 245 | 110 | 439 | 329 | 30mm |
| M22 | 303 | 136 | 597 | 448 | 32mm |
| M24 | 353 | 158 | 759 | 569 | 36mm |
| M27 | 459 | 206 | 1110 | 833 | 41mm |
| M30 | 561 | 251 | 1508 | 1131 | 46mm |
| M33 | 694 | 311 | 2052 | 1539 | 50mm |
| M36 | 817 | 366 | 2635 | 1976 | 55mm |
| M39 | 976 | 437 | 3411 | 2558 | 60mm |
| M42 | 1120 | 502 | 4215 | 3161 | 65mm |
| M45 | 1300 | 582 | 5242 | 3931 | 70mm |
| M48 | 1470 | 659 | 6322 | 4742 | 75mm |
This specification follows ISO (International Organization for Standardization) standards. ISO ensures cross-border compatibility, making it ideal for multinational projects, export equipment design, and global parts procurement.
Recommended tightening torque table for Grade 8.8 bolts (M3–M48) per ISO 898-1 and VDI 2230. Preload is set to 70% of the 640 MPa yield stress; torque values are shown for both dry (K=0.20) and lubricated (K=0.15) friction conditions. The most widely used grade for general machinery, equipment frames, and common fastening.