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Bolt Torque Chart

Suggested Starting Values

The below estimated torque calculations are only offered as a guide. Use of its content by anyone is the sole responsibility of that person and they assume all risk. Due to many variables that affect the torque-tension relationship like human error, surface texture, and lubrication the only way to determine the correct torque is through experimentation under actual joint and assembly conditions.

ASTM A307

Bolt Size TPI Proof Load (lbs)1 Clamp Load (lbs)2 Tightening Torque (ft lbs)
Galv+Waxed Galv Plain
1⁄4 20 1,053 790 2 4 3
5⁄16 18 1,735 1,302 3 8 7
3⁄8 16 2,567 1,925 6 15 12
7⁄16 14 3,521 2,640 10 24 19
1⁄2 13 4,700 3,525 15 37 29
9⁄16 12 6,028 4,521 21 53 42
5⁄8 11 7,485 5,614 29 73 58
3⁄4 10 11,062 8,297 52 130 104
7⁄8 9 15,301 11,476 84 209 167
1 8 20,071 15,053 125 314 251
11⁄8 7 25,271 18,953 178 444 355
11⁄4 7 32,093 24,070 251 627 501
13⁄8 6 38,254 28,690 329 822 657
11⁄2 6 46,534 34,900 436 1,091 873
13⁄4 5 62,928 47,196 688 1,721 1,377
2 41⁄2 82,800 62,100 1,035 2,588 2,070
21⁄4 41⁄2 107,640 80,730 1,514 3,784 3,027
21⁄2 4 132,480 99,360 2,070 5,125 4,140
23⁄4 4 163,282 122,461 2,806 7,016 5,613
3 4 197,726 148,295 3,707 9,268 7,415
31⁄4 4 235,152 176,364 4,777 11,941 9,553
31⁄2 4 275,890 206,917 6,035 15,088 12,070
33⁄4 4 319,939 239,954 7,499 18,746 14,997
4 4 366,970 275,227 9,174 22,936 18,348
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SAE Grade 2

Bolt Size TPI Proof Load (lbs) 1 Clamp Load (lbs) 2 Tightening Torque (ft lbs)
Galv+Waxed Galv Plain
1⁄4 20 1,750 1,313 3 7 5
5⁄16 18 2,900 2,175 6 14 11
3⁄8 16 4,250 3,188 10 25 20
7⁄16 14 5,850 4,388 16 40 32
1⁄2 13 7,800 5,850 24 61 49
9⁄16 12 10,000 7,500 35 88 70
5⁄8 11 12,400 9,300 48 121 97
3⁄4 10 18,400 13,800 86 216 173
7⁄8 9 15,200 11,400 83 208 166
1 8 20,000 15,000 125 313 250
11⁄8 7 25,200 18,900 177 443 354
11⁄4 7 32,000 24,000 250 625 500
13⁄8 6 38,100 28,575 327 819 655
11⁄2 6 46,400 34,800 435 1,088 870
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ASTM A325

Bolt Size TPI Tension Tightening Torque Range (ft lbs) (Min - Max)
Min Max Galv+Waxed Plain
1⁄2 13 12,000 14,000 50 - 58 100 - 117
5⁄8 11 19,000 23,000 99 - 120 198 - 240
3⁄4 10 28,000 34,000 175 - 213 350 - 425
7⁄8 9 39,000 47,000 284 - 343 569 - 685
1 8 51,000 61,000 425 - 508 850 - 1,017
11⁄8 7 64,000 77,000 600 - 722 1,200 - 1,444
11⁄4 7 81,000 98,000 844 - 1,021 1,687 - 2,042
13⁄8 6 97,000 117,000 1,111 - 1,341 2,223 - 2,681
11⁄2 6 118,000 143,000 1,475 - 1,788 2,950 - 3,575
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ASTM A449 / SAE Grade 5*

Bolt Size TPI Proof Load (lbs) 1 Clamp Load (lbs) 2 Tightening Torque (ft lbs)
Galv+Waxed Galv Plain
1⁄4 20 2,700 2,025 4 11 8
5⁄16 18 4,450 3,338 9 22 17
3⁄8 16 6,600 4,950 15 39 31
7⁄16 14 9,050 6,788 25 62 49
1⁄2 13 12,050 9,038 38 94 75
9⁄16 12 15,450 11,588 54 136 109
5⁄8 11 19,200 14,400 75 188 150
3⁄4 10 28,400 21,300 133 333 266
7⁄8 9 39,250 29,438 215 537 429
1 8 51,500 38,625 322 805 644
11⁄8 7 56,450 42,338 397 992 794
11⁄4 7 71,700 53,775 560 1,400 1,120
13⁄8 6 85,450 64,088 734 1,836 1,469
11⁄2 6 104,000 78,000 975 2,438 1,950
13⁄4 5 104,500 78,375 1,143 2,857 2,286
2 41⁄2 137,500 103,125 1,719 4,297 3,438
21⁄4 41⁄2 178,750 134,063 2,514 6,284 5,027
21⁄2 4 220,000 165,000 3,438 8,594 6,875
23⁄4 4 271,150 203,363 4,660 11,651 9,321
3 4 328,350 246,263 6,157 15,391 12,313
* SAE J429 grade 5 bolts do not exceed 1-1/2" diameter.
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ASTM A193 B7 / ASTM A320 L7 / ASTM A354 BC

Bolt Size TPI Proof Load (lbs) 1 Clamp Load (lbs) 2 Tightening Torque (ft lbs)
Galv+Waxed Galv Plain
1⁄4 20 3,350 2,513 5 13 10
5⁄16 18 5,500 4,125 11 27 21
3⁄8 16 8,150 6,113 19 48 38
7⁄16 14 11,150 8,363 30 76 61
1⁄2 13 14,900 11,175 47 116 93
9⁄16 12 19,100 14,325 67 168 134
5⁄8 11 23,750 17,813 93 232 186
3⁄4 10 35,050 26,288 164 411 329
7⁄8 9 48,500 36,375 265 663 530
1 8 63,650 47,738 398 995 796
11⁄8 7 80,100 60,075 563 1,408 1,126
11⁄8 8 82,934 62,201 583 1,458 1,166
11⁄4 7 101,750 76,313 795 1,987 1,590
11⁄4 8 105,006 78,754 820 2,051 1,641
13⁄8 6 121,300 90,975 1,042 2,606 2,085
13⁄8 8 129,492 97,119 1,113 2,782 2,226
11⁄2 6 147,550 110,663 1,383 3,458 2,767
11⁄2 8 156,687 117,515 1,469 3,672 2,938
13⁄4 5 199,500 149,625 2,182 5,455 4,364
13⁄4 8 218,400 163,800 - - 4,778
2 41⁄2 262,500 196,875 3,281 8,203 6,563
2 8 290,850 218,138 - - 7,271
21⁄4 41⁄2 341,250 255,938 4,799 11,997 9,598
21⁄4 8 373,801 280,351 - - 10,513
21⁄2 4 420,000 315,000 6,563 16,406 13,125
21⁄2 8 466,200 349,650 - - 14,569
23⁄4 4 468,500 351,263 8,050 20,124 16,100
23⁄4 8 515,851 386,888 - - 17,732
3 4 567,150 425,363 10,634 26,585 21,268
3 8 618,451 463,838 - - 23,192
31⁄4 4 674,500 505,875 13,701 34,252 27,402
31⁄4 8 730,550 547,913 - - 29,679
31⁄2 4 791,350 593,513 17,311 43,277 34,622
31⁄2 8 851,201 638,401 - - 37,240
33⁄4 4 917700 688275 21,509 53,771 43,017
33⁄4 8 982,300 736,725 - - 46,045
4 4 1052600 789450 26,315 65,788 52,630
4 8 1,121,950 841,463 - - 56,098
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ASTM A490

Bolt Size TPI Tension (lbs) Tightening Torque Range (ft lbs) (Min - Max)
Min Max Plain Lubricated
1⁄2 13 15,000 18,000 125 - 150 63 - 75
5⁄8 11 24,000 29,000 250 - 302 125 - 151
3⁄4 10 35,000 42,000 438 - 525 219 - 263
7⁄8 9 49,000 59,000 715 - 860 357 - 430
1 8 64,000 77,000 1,067 - 1,283 533 - 642
11⁄8 7 80,000 96,000 1,500 - 1,800 750 - 900
11⁄4 7 102,000 122,000 2,125 - 2,542 1,063 - 1,271
13⁄8 6 121,000 145,000 2,773 - 3,323 1,386 - 1,661
11⁄2 6 148,000 178,000 3,700 - 4,450 1,850 - 2,225
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ASTM A354-BD / SAE Grade 8*

Bolt Size TPI Proof Load (lbs) 1 Clamp Load (lbs) 2 Tightening Torque (ft lbs)
Plain Lubricated
1⁄4 20 3,800 2,850 12 6
5⁄16 18 6,300 4,725 25 12
3⁄8 16 9,300 6,975 44 22
7⁄16 14 12,750 9,563 70 35
1⁄2 13 17,050 12,788 107 53
9⁄16 12 21,850 16,388 154 77
5⁄8 11 27,100 20,325 212 106
3⁄4 10 40,100 30,075 376 188
7⁄8 9 55,450 41,588 606 303
1 8 72,700 54,525 909 454
11⁄8 7 91,550 68,663 1,287 644
11⁄4 7 120,000 90,000 1,875 938
13⁄8 6 138,600 103,950 2,382 1,191
11⁄2 6 168,600 126,450 3,161 1,581
13⁄4 5 228,000 171,000 4,988 2,494
2 41⁄2 300,000 225,000 7,500 3,750
21⁄4 41⁄2 390,000 292,500 10,969 5,484
21⁄2 4 480,000 360,000 15,000 7,500
23⁄4 4 517,650 388,238 17,794 8,897
3 4 626,850 470,138 23,507 11,753
31⁄4 4 745,500 559,125 30,286 15,143
31⁄2 4 874,650 655,988 38,266 19,133
33⁄4 4 1,014,300 760,725 47,545 23,773
4 4 1,163,400 872,550 58,100 29,085
* SAE J429 grade 8 bolts do not exceed 1-1/2″ diameter.
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