M30 bolt torque specifications (8.8, 10.9, 12.9)
An M30 x 3.5 class 8.8 bolt takes 1,117 ft-lb (1,515 N·m) dry, and class 10.9 takes 1,545 ft-lb (2,095 N·m). Both are for plain steel, dry threads (K 0.20) tightened to a clamp load of 75% of proof load.
Contents14 sections
Key takeaways
- Class 8.8 dry: 1,117 ft-lb (1,515 N·m); class 10.9 dry: 1,545 ft-lb (2,095 N·m).
- M30 x 2 fine carries about 11% more clamp load than M30 x 3.5.
- About 90% of the input torque goes into friction 1, so the thread condition sets most of the result.
- With moly paste (K 0.11) class 8.8 drops to 614 ft-lb 2.
Quick facts
| Coarse thread | M30 x 3.5 (561 mm²) |
|---|---|
| Fine thread | M30 x 2 (621 mm²) |
| Wrench, ISO 4014/4017 | 46 mm |
| Wrench, DIN 931/933 | 46 mm (same) |
M30 bolt specifications
| Thread | Pitch | Tensile stress area |
|---|---|---|
| M30 x 3.5 (coarse) | 3.5 mm pitch | 561.0 mm² |
| M30 x 2 (fine) | 2 mm pitch | 621.0 mm² |
| Wrench, ISO 4014/4017 | 46 mm1 | |
Stress areas from ISO 898-1 Table 43.
M30 torque by grade
| Grade | Plain, dry K 0.201 | Lubricated K 0.151 | Clamp load |
|---|---|---|---|
| Class 4.6 | 419 ft-lb568 N·m | 314 ft-lb426 N·m | 94.7 kN |
| Class 8.8 | 1,117 ft-lb1,515 N·m | 838 ft-lb1,136 N·m | 252.5 kN |
| Class 10.9 | 1,545 ft-lb2,095 N·m | 1,159 ft-lb1,572 N·m | 349.2 kN |
| Class 12.9 | 1,806 ft-lb2,449 N·m | 1,355 ft-lb1,837 N·m | 408.1 kN |
Calculated with T = K × D × F, where F is 75% of the bolt’s proof load1 and K is the nut factor for each condition. Real preload from a torque wrench scatters by about ±25%4. When the equipment maker gives a torque, use theirs. How these numbers are made.
M30 4.6 torque
Proof 225 MPa · yield 240 MPa · tensile 400 MPa3. Clamp load at 75% of proof: 94.7 kN (M30 x 3.5).
| Condition | K | M30 x 3.5 | M30 x 2 |
|---|---|---|---|
| Plain steel, dryAs-received black or plain finish, clean threads, no lubricant | 0.201 | 419 ft-lb568 N·m | 464 ft-lb629 N·m |
| Zinc-plated, dryClean zinc-plated threads, no added lubricant | 0.181 | 377 ft-lb511 N·m | 417 ft-lb566 N·m |
| Lubricated (oil or grease)Light oil or grease on the threads and under the nut or head | 0.151 | 314 ft-lb426 N·m | 348 ft-lb472 N·m |
| Copper or metal-free anti-seizeLoctite C5-A copper or N-7000 metal-free anti-seize | 0.165 | 335 ft-lb454 N·m | 371 ft-lb503 N·m |
| Moly pasteMolybdenum disulfide paste | 0.112 | 230 ft-lb312 N·m | 255 ft-lb346 N·m |
M30 8.8 torque
Proof 600 MPa · yield 660 MPa · tensile 830 MPa3. Clamp load at 75% of proof: 252.5 kN (M30 x 3.5).
| Condition | K | M30 x 3.5 | M30 x 2 |
|---|---|---|---|
| Plain steel, dryAs-received black or plain finish, clean threads, no lubricant | 0.201 | 1,117 ft-lb1,515 N·m | 1,237 ft-lb1,677 N·m |
| Zinc-plated, dryClean zinc-plated threads, no added lubricant | 0.181 | 1,005 ft-lb1,363 N·m | 1,113 ft-lb1,509 N·m |
| Lubricated (oil or grease)Light oil or grease on the threads and under the nut or head | 0.151 | 838 ft-lb1,136 N·m | 928 ft-lb1,258 N·m |
| Copper or metal-free anti-seizeLoctite C5-A copper or N-7000 metal-free anti-seize | 0.165 | 894 ft-lb1,212 N·m | 989 ft-lb1,341 N·m |
| Moly pasteMolybdenum disulfide paste | 0.112 | 614 ft-lb833 N·m | 680 ft-lb922 N·m |
M30 10.9 torque
Proof 830 MPa · yield 940 MPa · tensile 1040 MPa3. Clamp load at 75% of proof: 349.2 kN (M30 x 3.5).
| Condition | K | M30 x 3.5 | M30 x 2 |
|---|---|---|---|
| Plain steel, dryAs-received black or plain finish, clean threads, no lubricant | 0.201 | 1,545 ft-lb2,095 N·m | 1,711 ft-lb2,319 N·m |
| Zinc-plated, dryClean zinc-plated threads, no added lubricant | 0.181 | 1,391 ft-lb1,886 N·m | 1,540 ft-lb2,087 N·m |
| Lubricated (oil or grease)Light oil or grease on the threads and under the nut or head | 0.151 | 1,159 ft-lb1,572 N·m | 1,283 ft-lb1,740 N·m |
| Copper or metal-free anti-seizeLoctite C5-A copper or N-7000 metal-free anti-seize | 0.165 | 1,236 ft-lb1,676 N·m | 1,369 ft-lb1,856 N·m |
| Moly pasteMolybdenum disulfide paste | 0.112 | 850 ft-lb1,152 N·m | 941 ft-lb1,276 N·m |
M30 12.9 torque
Proof 970 MPa · yield 1100 MPa · tensile 1220 MPa3. Clamp load at 75% of proof: 408.1 kN (M30 x 3.5).
| Condition | K | M30 x 3.5 | M30 x 2 |
|---|---|---|---|
| Plain steel, dryAs-received black or plain finish, clean threads, no lubricant | 0.201 | 1,806 ft-lb2,449 N·m | 1,999 ft-lb2,711 N·m |
| Zinc-plated, dryClean zinc-plated threads, no added lubricant | 0.181 | 1,626 ft-lb2,204 N·m | 1,799 ft-lb2,440 N·m |
| Lubricated (oil or grease)Light oil or grease on the threads and under the nut or head | 0.151 | 1,355 ft-lb1,837 N·m | 1,499 ft-lb2,033 N·m |
| Copper or metal-free anti-seizeLoctite C5-A copper or N-7000 metal-free anti-seize | 0.165 | 1,445 ft-lb1,959 N·m | 1,599 ft-lb2,169 N·m |
| Moly pasteMolybdenum disulfide paste | 0.112 | 993 ft-lb1,347 N·m | 1,100 ft-lb1,491 N·m |
Coarse or fine pitch
M30 x 3.5 coarse has 561 mm² of stress area 3; M30 x 2 fine has 621 mm² 1, about 10.7% more. The gap between the two pitches, 1.5 mm, is the widest in this chart. In class 8.8 dry the fine thread takes 1,237 ft-lb instead of 1,117 ft-lb, 120 ft-lb more, and clamps 279.4 kN instead of 252.4 kN.
Class 8.8 above and below M16
Class 8.8 at M30 uses the over-16 mm values in ISO 898-1: 600 MPa proof stress and 830 MPa minimum tensile strength 3. The clamp load at 75% of proof is 252.4 kN (about 56,750 lbf) for 8.8 and 349.2 kN (about 78,510 lbf) for 10.9. Class 10.9 sits about 38% above 8.8, and 12.9 dry reaches 1,806 ft-lb (2,449 N·m).
M30 is the largest size in this chart, though ISO 898-1 tabulates coarse threads up to M39 3. Its class 8.8 torque is about twice that of M24.
Wrench size
M30 heads are 46 mm across the flats in both ISO 4014/4017 and DIN 931/933 1.
Which class you have
Look for the class symbol and maker’s mark on the head 3; see the bolt grades page. Class 4.6 at M30 is 419 ft-lb (568 N·m) dry, so applying the 8.8 value to a 4.6 bolt would put it far past proof.
Where friction takes the torque
Fastenal estimates that about 90% of tightening torque is lost to thread and under-head friction, with about 10% stretching the bolt 1. At 1,117 ft-lb, roughly 1,000 ft-lb goes into friction, so small changes in the thread surface move the clamp load a lot. NASA-STD-5020B assumes 35% preload variation for dry or as-received threads under torque control and 25% for lubricated ones 6; for a class 8.8 M30 dry, 35% is about ±88 kN around the 252 kN target.
When the chart does not apply
Match the torque to the thread condition. Class 8.8 M30 is 838 ft-lb oiled (K 0.15) 1 and 614 ft-lb with moly paste (K 0.11) 2. If you add an extension to the wrench to reach these values, correct the setting with the torque wrench extension calculator. For structural joints, see structural bolts; RCSC does not accept unverified table torque for calibrated-wrench installation 7.
Sources
- 1
- 2Henkel Corporation (LOCTITE), LOCTITE LB 8012 Moly Paste TDS, April 2015Checked 21 Oct 2026
- 3
- 4
- 5
- 6
- 7
Spotted a value that doesn’t match its source? Report an error
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