Bolt Stress to Bolt Torque Conversion Tables Load on Machine Bolts and Cold Rolled Steel Stud Bolts Under Torque Stress Nominal Number Diameter Area 7,500 psi 15,000 psi 30,000 psi Diameter of Threads of Root at Root Clamping Clamping Clamping of Bolt Per Inch of Thread of Thread Torque Force Torque Force Torque Force (inches) (inches) (sq. in.) (ft. lbs.) (lbs./bolt) (ft. lbs.) (lbs./bolt) (ft. lbs.) (lbs./bolt)
1/4 5/16 3/8 7/16 1/2 9/16 5/8 3/4 7/8 1 1-1/8 1-1/4 1-3/8 1-1/2 1-5/8 1-3/4 1-7/8 2
20 18 16 14 13 12 11 10 9 8 7 7 6 6 5-1/2 5 5 4-1/2
0.185 0.240 0.294 0.345 0.400 0.454 0.507 0.620 0.731 0.838 0.939 1.064 1.158 1.283 1.389 1.490 1.615 1.711
0.027 0.045 0.068 0.093 0.126 0.162 0.202 0.302 0.419 0.551 0.693 0.890 1.054 1.294 1.515 1.744 2.049 2.300
1 2 3 5 8 12 15 25 40 62 98 137 183 219 300 390 525 563
203 338 510 698 945 1,215 1,515 2,265 3,143 4,133 5,190 6,675 7,905 9,705 11,363 13,080 15,368 17,250
2 4 6 10 15 23 30 50 80 123 195 273 365 437 600 775 1,050 1,125
405 675 1,020 1,395 1,890 2,430 3,030 4,530 6,285 8,265 10,380 13,350 15,810 19,410 22,725 26,160 30,735 34,500
4 8 12 20 30 45 60 100 160 245 390 545 730 875 1,200 1,550 2,100 2,250
810 1,350 2,040 2,790 3,780 4,860 6,060 9,060 12,570 16,530 20,760 26,700 31,620 38,820 45,450 52,320 61,470 69,000
Load on Alloy Steel Stud Bolts Under Torque Stress Nominal Number Diameter Area 30,000 psi 45,000 psi 60,000 psi Diameter of Threads of Root at Root Clamping Clamping Clamping of Bolt Per Inch of Thread of Thread Torque Force Torque Force Torque Force (inches) (inches) (sq. in.) (ft. lbs.) (lbs./bolt) (ft. lbs.) (lbs./bolt) (ft. lbs.) (lbs./bolt)
1/4 5/16 3/8 7/16 1/2 9/16 5/8 3/4 7/8 1 1-1/8 1-1/4 1-3/8 1-1/2 1-5/8 1-3/4 1-7/8 2 2-1/4 2-1/2 2-3/4 3
20 18 16 14 13 12 11 10 9 8 8 8 8 8 8 8 8 8 8 8 8 8
0.185 0.240 0.294 0.345 0.400 0.454 0.507 0.620 0.731 0.838 0.963 1.088 1.213 1.338 1.463 1.588 1.713 1.838 2.088 2.338 2.588 2.838
0.027 0.045 0.068 0.093 0.126 0.162 0.202 0.302 0.419 0.551 0.728 0.929 1.155 1.405 1.680 1.980 2.304 2.652 3.423 4.292 5.259 6.324
4 8 12 20 30 45 60 100 160 245 355 500 680 800 1,100 1,500 2,000 2,200 3,180 4,400 5,920 7,720
These tables are for reference only. See torque tables for recommended installation torques. Values shown in these tables are based on steel bolting that has been well-lubricated with heavy graphite and oil mixture. Research has shown
C-44
810 1,350 2,040 2,790 3,780 4,860 6,060 9,060 12,570 16,530 21,840 27,870 34,650 42,150 50,400 59,400 69,120 79,560 102,690 128,760 157,770 189,720
6 12 18 30 45 68 90 150 240 368 533 750 1,020 1,200 1,650 2,250 3,000 3,300 4,770 6,600 8,800 11,580
1,215 2,025 3,060 4,185 5,670 7,290 9,090 13,590 18,855 24,795 32,760 41,805 51,975 63,225 75,600 89,100 103,680 119,340 154,035 193,140 236,655 284,580
8 16 24 40 60 90 120 200 320 490 710 1,000 1,360 1,600 2,200 3,000 4,000 4,400 6,360 8,800 11,840 15,440
1,620 2,700 4,080 5,580 7,560 9,720 12,120 18,120 25,140 33,060 43,680 55,740 69,300 84,300 100,800 118,800 138,240 159,120 205,380 257,520 315,540 379,440
that a non-lubricated bolt has about 50% of the efficiency of a well-lubricated bolt. It has been further found that different lubricants produce results varying between the limit of 50% and 100% of the tabulated stress figures.
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