Strengths of:

This page is based on information from http://ourworld.compuserve.com/homepages/MJVanVoorhis/T205.htm. Another good source is here, providing English and Metric values, and pictures of the head-markings for different bolt grades. Extensive data on Metric bolt properties is here, and the same site's home page gives links to a lot of other materials, analysis, and fastener data.

"ksi" indicates load in ___. There are 6.8947573 MPa per ksi.

Strength of standard bolts

Sizes up to 1/4", torque in inch-pounds

Size and pitch Nominal diameter, in Stress Area, in2 Grade Proof load, ksi Clamp load, lbs Assembly torque, dry, in*lb Assembly torque, lubricated, in*lb
Size # 4
# 4-40 0.1120 0.0060 2 55 248 5 4
# 4-40 0.1120 0.0060 5 85 384 18 6
# 4-40 0.1120 0.0060 8 120 542 12 9
# 4-48 0.1120 0.0066 2 55 272 6 4
# 4-48 0.1120 0.0060 5 85 421 19 17
# 4-48 0.1120 0.0060 8 120 594 13 9
Size # 6
# 6-32 0.1380 0.0091 2 55 374 10 7
# 6-32 0.1380 0.0091 5 85 579 15 11
# 6-32 0.1380 0.0091 8 120 817 22 8
# 6-36 0.1380 0.0101 2 55 418 11 8
# 6-36 0.1380 0.0101 5 85 646 17 13
# 6-36 0.1380 0.0101 8 120 912 25 18
Size # 8
# 8-32 0.1640 0.0140 2 55 577 18 14
# 8-32 0.1640 0.0140 5 85 893 29 21
# 8-32 0.1640 0.0140 8 120 1260 41 31
# 8-36 0.1640 0.0147 2 55 607 19 14
# 8-36 0.1640 0.0147 5 85 938 30 23
# 8-36 0.1640 0.0147 8 120 1325 43 32
Size # 10
#10-24 0.1900 0.0175 2 55 723 27 20
#10-24 0.1900 0.0175 5 85 1117 42 31
#10-24 0.1900 0.0175 8 120 1577 59 44
#10-32 0.1900 0.0200 2 55 824 31 23
#10-32 0.1900 0.0200 5 85 1274 48 36
#10-32 0.1900 0.0200 8 120 1799 68 51
Size 1/4"
1/4-20 0.2500 0.0318 2 55 723 65 49
1/4-20 0.2500 0.0318 5 85 1117 101 76
1/4-20 0.2500 0.0318 8 120 1577 143 107
1/4-20 0.2500 0.0318 9 145 3460 173 129
1/4-28 0.2500 0.0364 2 55 824 75 56
1/4-28 0.2500 0.0364 5 85 1274 115 86
1/4-28 0.2500 0.0364 8 120 1799 163 122
1/4-28 0.2500 0.0364 9 145 3955 197 148

Sizes from 5/16 up, torque in foot-pounds

Size and pitch Nominal diameter Stress Area, in2 Grade Proof load, ksi Clamp load, lbs Assembly torque, dry, ft*lb Assembly torque, lubricate, ft*lb
Size 5/16"
5/16-18 0.3125 0.0524 2 55 2162 11 8
5/16-18 0.3125 0.0524 5 85 3342 17 13
5/16-18 0.3125 0.0524 8 120 4718 24 18
5/16-18 0.3125 0.0524 9 145 5701 29 22
5/16-24 0.3125 0.0581 2 55 2395 11 8
5/16-24 0.3125 0.0581 5 85 3701 19 14
5/16-24 0.3125 0.0581 8 120 5225 27 20
5/16-24 0.3125 0.0581 9 145 6314 32 24
Size 3/8"
3/8-18 0.3750 0.0775 2 55 3196 19 14
3/8-18 0.3750 0.0775 5 85 4939 30 23
3/8-18 0.3750 0.0775 8 120 6974 43 32
3/8-18 0.3750 0.0775 9 145 8427 52 39
3/8-24 0.3750 0.0878 2 55 3622 22 16
3/8-24 0.3750 0.0878 5 85 5599 34 26
3/8-24 0.3750 0.0878 8 120 7904 49 37
3/8-24 0.3750 0.0878 9 145 9551 59 44
Size 7/16"
7/16-14 0.4375 0.1063 2 55 4385 31 23
7/16-14 0.4375 0.1063 5 85 6777 49 37
7/16-14 0.4375 0.1063 8 120 9567 69 52
7/16-14 0.4375 0.1063 9 145 11561 84 63
7/16-20 0.4375 0.1187 2 55 4897 35 26
7/16-20 0.4375 0.1187 5 85 7568 55 41
7/16-20 0.4375 0.1187 8 120 10684 77 58
7/16-20 0.4375 0.1187 9 145 12910 94 70
Size 1/2"
1/2-13 0.5000 0.1419 2 55 5853 48 36
1/2-13 0.5000 0.1419 5 85 9046 75 56
1/2-13 0.5000 0.1419 8 120 12770 106 79
1/2-13 0.5000 0.1419 9 145 15431 128 96
1/2-20 0.5000 0.1600 2 55 6598 54 41
1/2-20 0.5000 0.1600 5 85 10197 84 63
1/2-20 0.5000 0.1600 8 120 14395 153 115
1/2-20 0.5000 0.1600 9 145 17394 144 108
Size 9/16"
9/16-12 0.5625 0.1819 2 55 7505 70 52
9/16-12 0.5625 0.1819 5 85 11598 108 81
9/16-12 0.5625 0.1819 8 120 16375 106 79
9/16-12 0.5625 0.1819 9 145 19786 185 139
9/16-18 0.5625 0.2030 2 55 8372 78 58
9/16-18 0.5625 0.2030 5 85 12940 121 90
9/16-18 0.5625 0.2030 8 120 18268 171 128
9/16-18 0.5625 0.2030 9 145 22074 206 155
Size 5/8"
5/8-11 0.6250 0.2260 2 55 9322 97 72
5/8-11 0.6250 0.2260 5 85 14407 150 112
5/8-11 0.6250 0.2260 8 120 20340 211 158
5/8-11 0.6250 0.2260 9 145 24577 256 192
5/8-18 0.6250 0.2560 2 55 10558 109 82
5/8-18 0.6250 0.2560 5 85 16317 169 127
5/8-18 0.6250 0.2560 8 120 23036 239 179
5/8-18 0.6250 0.2560 9 145 27835 289 217
Size 3/4"
3/4-10 0.7500 0.3345 2 55 13796 97 72
3/4-10 0.7500 0.3345 5 85 21321 266 199
3/4-10 0.7500 0.3345 8 120 30101 376 282
3/4-10 0.7500 0.3345 9 145 36372 454 340
3/4-16 0.7500 0.3730 2 55 15384 192 144
3/4-16 0.7500 0.3730 5 85 23776 297 222
3/4-16 0.7500 0.3730 8 120 33566 419 314
3/4-16 0.7500 0.3730 9 145 40559 506 380
Size 7/8"
7/8-9 0.8750 0.4617 2 33 13796 97 72
7/8-9 0.8750 0.4617 5 85 21321 266 199
7/8-9 0.8750 0.4617 8 120 30101 376 282
7/8-9 0.8750 0.4617 9 145 36372 454 340
7/8-14 0.8750 0.5095 2 33 15384 192 144
7/8-14 0.8750 0.5095 5 85 23776 297 222
7/8-14 0.8750 0.5095 8 120 33566 419 314
7/8-14 0.8750 0.5095 9 145 40559 506 380
Size 1"
1-8 1.0000 0.6057 2 33 14992 249 187
1-8 1.0000 0.6057 5 85 38616 643 482
1-8 1.0000 0.6057 8 120 54517 908 681
1-8 1.0000 0.6057 9 145 65874 1097 823
1-12 1.0000 0.6630 2 33 16410 273 205
1-12 1.0000 0.6630 5 85 42268 704 528
1-12 1.0000 0.6630 8 120 59673 994 745
1-12 1.0000 0.6630 9 145 72105 1201 901
Size 1 1/8"
1 1/8-7 1.1250 0.7633 2 33 18891 354 265
1 1/8-7 1.1250 0.7633 5 74 42361 794 595
1 1/8-7 1.1250 0.7633 8 120 68694 1288 966
1 1/8-7 1.1250 0.7633 9 145 83066 1556 1167
1 1/8-12 1.1250 0.8557 2 33 21179 397 297
1 1/8-12 1.1250 0.8557 5 74 47492 890 667
1 1/8-12 1.1250 0.8557 8 120 77014 1444 1083
1 1/8-12 1.1250 0.8557 9 145 93059 1477 1308
Size 1 1/4"
1 1/4-7 1.2500 0.9691 2 33 23985 499 374
1 1/4-7 1.2500 0.9691 5 74 53785 1120 840
1 1/4-7 1.2500 0.9691 8 120 87220 1817 1362
1 1/4-7 1.2500 0.9691 9 145 105391 2195 1646
1 1/4-12 1.2500 1.0729 2 33 26555 553 414
1 1/4-12 1.2500 1.0729 5 74 59548 1240 930
1 1/4-12 1.2500 1.0729 8 120 96565 2011 1508
1 1/4-12 1.2500 1.0729 9 145 116682 2430 1823
Size 1 3/8"
1 3/8-6 1.3750 1.1549 2 33 28583 655 491
1 3/8-6 1.3750 1.1549 5 74 64096 1468 1101
1 3/8-6 1.3750 1.1549 8 120 103939 2381 1786
1 3/8-6 1.3750 1.1549 9 145 125593 2878 2158
1 3/8-12 1.3750 1.3147 2 33 32539 745 559
1 3/8-12 1.3750 1.3147 5 74 72966 1672 1254
1 3/8-12 1.3750 1.3147 8 120 118324 2711 2033
1 3/8-12 1.3750 1.3147 9 145 142974 3276 2457
Size 1 1/2"
1 1/2-6 1.5000 1.4053 2 33 34780 869 652
1 1/2-6 1.5000 1.4053 5 74 77891 1949 1462
1 1/2-6 1.5000 1.4053 8 120 126472 3161 2371
1 1/2-6 1.5000 1.4053 9 145 152821 3820 2865
1 1/2-12 1.5000 1.5810 2 33 39130 978 733
1 1/2-12 1.5000 1.5810 5 74 87746 2193 1645
1 1/2-12 1.5000 1.5810 8 120 142292 3557 2667
1 1/2-12 1.5000 1.5810 9 145 171936 4298 3223
Size 1 3/4"
1 3/4-5 1.7500 1.8995 2 33 47011 1371 1028
1 3/4-5 1.7500 1.8995 5 74 105420 3074 2306
1 3/4-5 1.7500 1.8995 8 120 170951 4986 3739
Size 2"
2-4.5 2.0000 2.4982 2 33 61831 2061 1545
2-4.5 2.0000 2.4982 5 74 138651 4621 3466
2-4.5 2.0000 2.4982 8 120 224840 7497 5621
Size 2 1/4"
2 1/4-4.5 2.2500 3.2477 2 33 80380 3014 2260
2 1/4-4.5 2.2500 3.2477 5 74 180246 6759 5069
2 1/4-4.5 2.2500 3.2477 8 120 292292 10960 8220
Size 2 1/2"
2 1/2-4 2.5000 3.9988 2 33 98971 4213 3092
2 1/2-4 2.5000 3.9988 5 74 221935 9247 6935
2 1/2-4 2.5000 3.9988 8 120 359894 14995 11246
Size 2 3/4"
2 3/4-4 2.7500 4.9340 2 33 122166 5597 4197
2 3/4-4 2.7500 4.9340 5 74 273837 12550 9413
2 3/4-4 2.7500 4.9340 8 120 444061 20352 15264
Size 3"
3-4 3.0000 5.9674 2 33 147692 7384 5538
3-4 3.0000 5.9674 5 74 331189 16559 12419
3-4 3.0000 5.9674 8 120 537063 26853 20139
Size 3 1/4"
3 1/4-4 3.2500 7.0989 2 33 175698 9516 7137
3 1/4-4 3.2500 7.0989 5 74 393989 21341 16005
3 1/4-4 3.2500 7.0989 8 120 638901 34607 25955
Size 3 1/2"
3 1/2-4 3.5000 8.3286 2 33 206133 12024 9018
3 1/2-4 3.5000 8.3286 5 74 462238 26963 20222
3 1/2-4 3.5000 8.3286 8 120 749575 43725 32793
Size 3 3/4"
3 3/4-4 3.7500 9.6565 2 33 238998 14937 11203
3 3/4-4 3.7500 9.6565 5 74 535935 33495 25121
3 3/4-4 3.7500 9.6565 8 120 869085 54317 40738
Size 4"
4-4 4.0000 11.0826 2 33 274293 18286 13714
4-4 4.0000 11.0826 5 74 615082 41005 30754
4-4 4.0000 11.0826 8 120 997430 66495 49871
Size 4 1/4"
4 1/4-4 4.2500 12.6068 2 33 312018 22101 16575
4 1/4-4 4.2500 12.6068 5 74 699677 49560 37170
4 1/4-4 4.2500 12.6068 8 120 1134611 80368 60276
Size 4 1/2"
4 1/2-4 4.5000 14.2292 2 33 352172 26212 19809
4 1/2-4 4.5000 14.2292 5 74 789720 59229 44421
4 1/2-4 4.5000 14.2292 8 120 1280628 96047 72035

Shear strengths of bolts by diameter

This information is derived from data here.

Bolt Safe Working Loads (lbs)

Safe tensile load at 6,000 psi load; safe shear strength at 7500 psi load)

Note: These values seems awfully low to me. For example, I can't imagine a 1/4" bolt failing at these loads. To test, I just screwed a plain old hex-head 1/4 x 3 1/2 screw into the bottom of my workbench, with about 2 1/2" left visible, and the head holding up a long piece of angle iron. Then I hung weights on the angle iron. When that got boring, I squeezed my toes in on top of the angle iron too, got my balance, and bounced a few times. The angle iron deformed a little, but the bolt didn't show the least sign of strain. This totalled about 225 pounds not counting the bouncing effect -- way over the 160 pound rating shown below.
Bolt
Diameter
(inches)		 NF Thread Grade 2 Iron Bolt
Shear
(at thread root)		 Shear
(Full Bolt)		 Tensile
(at thread root)
1/4 200 370 160
5/16 340 575 270
3/8 510 830 410
7/16 700 1130 560
1/2 940 1470 760
9/16      
5/8 1510 2300 1210
3/4 2260 3310 1810
7/8 3140 4510 2520
1 4130 5890 3300
1 1/8 5200 7450 4160
1 1/4 6670 9200 5350
1 3/8 7900 11130 6340
1 1/2 9700 13250 7700
1 5/8 11360 15550 9090
1 3/4 13080 18000 10470
1 7/8 15370 20700 12300
2 17250 23560 13800

Bolt Tensile Strength (Breaking Strength - pounds)

Bolt
Diameter
(inches)		 Grade 2 Grade 5 Grade 8
Coarse Fine Coarse Fine Coarse Fine
1/4 2350 2700 3800 4350 4750 5450
5/16 3900 4300 6300 6950 7850 8700
3/8            
7/16 7850 8800 12800 14400 15900 17800
1/2 10500 11800 17000 19200 21300 24000
9/16 13500 15000 21800 24400 27300 30400
5/8 16700 18900 27100 30700 33900 38400
3/4 24700 27600 40100 44800 50100 56000

Threaded rods

This information is derived from data here. There are many types of rods; for example, they can be had in the same numbered strength grades as bolts, and in various materials such as brass, stainless steel, fiberglas, and so on. Depending on various factors, the strength will vary greatly.

High Tensile B7S Coil Rod or B8S UNC Threaded Bar

Thread
Diameter		 Thread Pitch Safe Working Load
(~2:1 Safety Factor)		 Max Working Load
to Elastic Limit		 Average
Ultimate Strength
Coil
Thread		 V
Thread
3/8"
(10mm)		 8 16 NC 4,900 lbs.
(21.8 kN)		 7,500 lbs.
(33.4 kN)		 9,800lbs.
(43.6 kN)
1/2"
(12mm)		 6 13 NC 9,000 lbs.
(40.0 kN)		 13,000 lbs.
(57.8 kN)		 18,000 lbs.
(80.1 kN)
5/8"
(16mm)		 4-1/2 11 NC 11,250 lbs.
(50.0 kN)		 18,000 lbs.
(80.0 kN)		 22,500 lbs.
(100.0 kN)
3/4"
(20mm)		 4-1/2 10 NC 19,000 lbs.
(84.5 kN)		 30,000 lbs.
(133.5 kN)		 38,000 lbs.
(169.0 kN)
7/8"
(22mm)		 4-1/2 9 NC 29,000 lbs.
(129.0 kN)		 46,000 lbs.
(204.6 kN)		 58,000 lbs.
(258.0 kN)
1"
(25mm)		 3-1/2 8 NC 37,500 lbs.
(166.8 kN)		 60,000 lbs.
(266.8 kN)		 75,000 lbs.
(333.5 kN)
1-1/8"
(30mm)		 3-1/2 - 40.500 lbs.
(180.0 kN)		 62,000 lbs.
(283.8 kN)		 81,000 lbs.
(359.8 kN)
1-1/4"
(32mm)		 3-1/2 7 NC 51,000 lbs.
(254.2 kN)		 79,000 lbs.
(381.3 kN)		 102,00 lbs.
(508.3 kN)
1-1/2"
(38mm)		 3-1/2 - 70,000 lbs.
(311.4 kN)		 112,000 lbs.
(498.2 kN)		 140,000 lbs.
(622.8 kN)
2"
(51mm)		 - 6 UN 139,000 lbs.
(656.7 kN)		 215,000 lbs.
(1,080.3 kN)		 279,000 lbs.
(1,313.0 kN)

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