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Shah Steel & Alloys

Shah Steel & Alloys

Shah Steel & Alloys

Shah Steel & Alloys

Shah Steel & Alloys

Bolt Weight Chart

pounds (lbs) per 100 pieces

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 1145 859 2 4 4
5⁄16 18 1886 1415 4 9 7
3⁄8 16 2790 2093 7 16 13
7⁄16 14 3827 2870 10 26 21
1⁄2 13 5108 3831 16 40 32
9⁄16 12 6552 4914 23 58 46
5⁄8 11 8136 6102 32 79 64
3⁄4 10 12024 9018 56 141 113
7⁄8 9 15200 11400 83 208 166
1 8 20000 15000 125 313 250
11⁄8 7 25200 18900 177 443 354
11⁄4 7 32000 24000 250 625 500
13⁄8 6 38100 28575 327 819 655
11⁄2 6 46400 34800 435 1088 870
13⁄4 5 68400 51300 748 1870 1496
2 41⁄2 90000 67500 1125 2813 2250
21⁄4 41⁄2 117000 87750 1645 4113 3291
21⁄2 4 144000 108000 2250 5625 4500
23⁄4 4 177480 133110 3050 7626 6101
3 4 214920 161190 4030 10074 8060
31⁄4 4 255600 191700 5192 12980 10384
31⁄2 4 299880 224910 6560 16400 13120
33⁄4 4 347760 260820 8151 20377 16301
4 4 398880 299160 9972 24930 19944

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 1750 1313 3 7 5
5⁄16 18 2900 2175 6 14 11
3⁄8 16 4250 3188 10 25 20
7⁄16 14 5850 4388 16 40 32
1⁄2 13 7800 5850 24 61 49
9⁄16 12 10000 7500 35 88 70
5⁄8 11 12400 9300 48 121 97
3⁄4 10 18400 13800 86 216 173
7⁄8 9 15200 11400 83 208 166
1 8 20000 15000 125 313 250
11⁄8 7 25200 18900 177 443 354
11⁄4 7 32000 24000 250 625 500
13⁄8 6 38100 28575 327 819 655
11⁄2 6 46400 34800 435 1088 870

ASTM A325

Bolt Size TPI Tension Tightening Torque Range (ft lbs) (Min - Max)
Min Max Galv+Waxed Plain
1⁄2 13 12000 14000 50 - 58 100 - 117
5⁄8 11 19000 23000 99 - 120 198 - 240
3⁄4 10 28000 34000 175 - 213 350 - 425
7⁄8 9 39000 47000 284 - 343 569 - 685
1 8 51000 61000 425 - 508 850 - 1017
11⁄8 7 56000 67000 525 - 625 1050 - 1256
11⁄4 7 71000 85000 740 - 885 1479 - 1771
13⁄8 6 85000 102000 974 - 1169 1948 - 2338
11⁄2 6 103000 124000 1288 - 1550 2575 - 3100

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 2700 2025 4 11 8
5⁄16 18 4450 3338 9 22 17
3⁄8 16 6600 4950 15 39 31
7⁄16 14 9050 6788 25 62 49
1⁄2 13 12050 9038 38 94 75
9⁄16 12 15450 11588 54 136 109
5⁄8 11 19200 14400 75 188 150
3⁄4 10 28400 21300 133 333 266
7⁄8 9 39250 29438 215 537 429
1 8 51500 38625 322 805 644
11⁄8 7 56450 42338 397 992 794
11⁄4 7 71700 53775 560 1400 1120
13⁄8 6 85450 64088 734 1836 1469
11⁄2 6 104000 78000 975 2438 1950
13⁄4 5 104500 78375 1143 2857 2286
2 41⁄2 137500 103125 1719 4297 3438
21⁄4 41⁄2 178750 134063 2514 6284 5027
21⁄2 4 220000 165000 3438 8594 6875
23⁄4 4 271150 203363 4660 11651 9321
3 4 328350 246263 6157 15391 12313

SAE J429 grade 5 bolts do not exceed 1-1/2" diameter.

ASTM A193 B7

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
8 82,934 62,201 583 1,458 1,166
11⁄4 7 101,750 76,313 795 1,987 1,590
8 105,006 78,754 820 2,051 1,641
13⁄8 6 121,300 90,975 1,042 2,606 2,085
8 129,492 97,119 1,113 2,782 2,226
11⁄2 6 147,550 110,663 1,383 3,458 2,767
8 156,687 117,515 1,469 3,672 2,938
13⁄4 5 199,500 149,625 - - 4,364
8 218,400 163,800 - - 4,778
2 41⁄2 262,500 196,875 - - 6,563
8 290,850 218,138 - - 7,271
21⁄4 41⁄2 341,250 255,938 - - 9,598
8 373,801 280,351 - - 10,513
21⁄2 4 420,000 315,000 - - 13,125
8 466,200 349,650 - - 14,569
23⁄4 4 468,500 351,263 - - 16,100
8 515,851 386,888 - - 17,732
3 4 567,150 425,363 - - 21,268
8 618,451 463,838 - - 23,192
31⁄4 4 674,500 505,875 - - 27,402
8 730,550 547,913 - - 29,679
31⁄2 4 791,350 593,513 - - 34,622
8 851,201 638,401 - - 37,240
33⁄4 4 917700 688275 - - 43017
8 982,300 736,725 - - 46,045
4 4 1052600 789450 - - 52630
8 1,121,950 841,463 - - 56,098

ASTM A490

Bolt Size TPI Tension (lbs) Tightening Torque Range (ft lbs) (Min - Max)
Min Max Lubricated Plain
1⁄2 13 15000 18000 63 - 75 125 - 150
5⁄8 11 24000 29000 125 - 151 250 - 302
3⁄4 10 35000 42000 219 - 263 438 - 525
7⁄8 9 49000 59000 357 - 430 715 - 860
1 8 64000 77000 533 - 642 1067 - 1283
11⁄8 7 80000 96000 750 - 900 1500 - 1800
11⁄4 7 102000 122000 1063 - 1271 2125 - 2542
13⁄8 6 121000 145000 1386 - 1661 2773 - 3323
11⁄2 6 148000 178000 1850 - 2225 3700 - 4450

ASTM A354-BD / SAE GRADE 8

Bolt Size TPI Proof 
Load (lbs) 1
Clamp 
Load (lbs) 2
Tightening Torque (ft lbs)
Lubricated Plain
1⁄4 20 3800 2850 6 12
5⁄16 18 6300 4725 12 25
3⁄8 16 9300 6975 22 44
7⁄16 14 12750 9563 35 70
1⁄2 13 17050 12788 53 107
9⁄16 12 21850 16388 77 154
5⁄8 11 27100 20325 106 212
3⁄4 10 40100 30075 188 376
7⁄8 9 55450 41588 303 606
1 8 72700 54525 454 909
11⁄8 7 91550 68663 644 1287
11⁄4 7 120000 90000 938 1875
13⁄8 6 138600 103950 1191 2382
11⁄2 6 168600 126450 1581 3161
13⁄4 5 228000 171000 2494 4988
2 41⁄2 300000 225000 3750 7500
21⁄4 41⁄2 390000 292500 5484 10969
21⁄2 4 480000 360000 7500 15000
23⁄4 4 517650 388238 8897 17794
3 4 626850 470138 11753 23507
31⁄4 4 745500 559125 15143 30286
31⁄2 4 874650 655988 19133 38266
33⁄4 4 1014300 760725 23773 47545
4 4 1163400 872550 29085 58100


SAE J429 grade 8 bolts do not exceed 1-1/2" diameter.

1 - Proofload is the published number that full size headed bolts are tested to. The bolt is stressed up to the proofload value, and if there is no deformation, elongation, or fracture, then the bolt is deemed to have passed. For bolting specifications that do not have a published proofload, it is usually calculated at 92% of ultimate yield strength.
2 - Clampload is calculated at 75% of proofload. This is done to allow a safety buffer so that the bolt does not get too close to the proofload value. If you exceed the proofload value when tensioning the bolt, you run the risk of bolt failure. Clampload is only a estimated number, there maybe situations where the engineer calls for the bolts to be tensioned to a different value.

    Notes:

  1. Values calculated using industry accepted formula T = KDP where T = Torque, K = torque coefficient (dimensionless), D = nominal diameter (inches), P = bolt clamp load, lb.
  2. K values: waxed (e.g. pressure wax as supplied on high strength nuts) = .10, hot dip galvanized = .25, and plain non-plated bolts (as received) = .20.
  3. Torque has been converted into ft/lbs by dividing the result of the formula by 12
  4. All calculations are for Coarse Thread Series (UNC).
  5. Grade 2 calculations only cover fasteners 1⁄4"-3⁄4" in diameter up to 6" long; for longer fasteners the torque is reduced significantly.
  6. Clamp loads are based on 75% of the minimum proof loads for each grade and size.
  7. Proof load, stress area, yield strength, and other data is based on IFI 7th Edition (2003) Technical Data N-68, SAE J429, ASTM A307, A325, A354, A449, and A490.