Bolt Torque worksheet

1. Estimated tightening torque: 467.52 lbf·in

1. Convert the clamp load to N

   $\mathrm{9,500}\text{\hspace{0.17em}lbf}\times 4.4482216153$$=\mathrm{42,258.105345}\text{\hspace{0.17em}N}$

2. Find the tightening torque T: nut factor K × bolt diameter D × clamp load F

   $0.25\times 5\text{\hspace{0.17em}mm}\times \mathrm{42,258.105345}\text{\hspace{0.17em}N}$$=\mathrm{52,822.631681}\text{\hspace{0.17em}N·mm}$

3. Convert to lbf·in

   $\mathrm{52,822.631681}\text{\hspace{0.17em}N·mm}\times 0.0088507458$$=467.519685\text{\hspace{0.17em}lbf·in}$

2. Estimated tightening torque: 127.77 N·m

1. Find the bolt's effective cross-section through the threads (tensile stress area) for 9/16-12 UNC. D is the diameter: (π/4) × (D − 0.9743 × pitch)²

   $\frac{\text{π}}{4}\times {\left(0.5625-0.9743\times 0.08333333\right)}^2$$=0.181944\text{\hspace{0.17em}in²}$

2. Find the proof load, the most the bolt can hold without stretching for good: proof strength × stress area

   $\mathrm{85,000}\text{\hspace{0.17em}psi}\times 0.181944\text{\hspace{0.17em}in²}$$=\mathrm{15,465.201013}\text{\hspace{0.17em}lbf}$

3. Set the clamp load you're aiming for: 65% of the proof load

   $\mathrm{15,465.201013}\text{\hspace{0.17em}lbf}\times \mathrm{65\%}$$=\mathrm{10,052.380659}\text{\hspace{0.17em}lbf}$

4. Find the tightening torque T: nut factor K × bolt diameter D × clamp load F

   $0.2\times 0.5625\text{\hspace{0.17em}in}\times \mathrm{10,052.380659}\text{\hspace{0.17em}lbf}$$=\mathrm{1,130.892824}\text{\hspace{0.17em}lbf·in}$

5. Convert to N·m

   $\mathrm{1,130.892824}\text{\hspace{0.17em}lbf·in}\times 0.112984829$$=127.773732\text{\hspace{0.17em}N·m}$

3. Estimated tightening torque: 84.74 N·m

1. Find the tightening torque T: nut factor K × bolt diameter D × clamp load F

   $0.2\times 0.5\text{\hspace{0.17em}in}\times \mathrm{7,500}\text{\hspace{0.17em}lbf}$$=750\text{\hspace{0.17em}lbf·in}$

2. Convert to N·m

   $750\text{\hspace{0.17em}lbf·in}\times 0.112984829$$=84.738622\text{\hspace{0.17em}N·m}$

4. Estimated tightening torque: 506.25 lbf·in

1. Find the tightening torque T: nut factor K × bolt diameter D × clamp load F

   $0.15\times 0.375\text{\hspace{0.17em}in}\times \mathrm{9,000}\text{\hspace{0.17em}lbf}$$=506.25\text{\hspace{0.17em}lbf·in}$

5. Estimated tightening torque: 0.06 kN·m

1. Convert the clamp load to N

   $\mathrm{7,000}\text{\hspace{0.17em}lbf}\times 4.4482216153$$=\mathrm{31,137.551307}\text{\hspace{0.17em}N}$

2. Find the tightening torque T: nut factor K × bolt diameter D × clamp load F

   $0.2\times 10\text{\hspace{0.17em}mm}\times \mathrm{31,137.551307}\text{\hspace{0.17em}N}$$=\mathrm{62,275.102614}\text{\hspace{0.17em}N·mm}$

3. Convert to kN·m

   $\mathrm{62,275.102614}\text{\hspace{0.17em}N·mm}\times 0.000001$$=0.062275\text{\hspace{0.17em}kN·m}$

6. Estimated tightening torque: 135.31 lbf·in

1. Find the bolt's effective cross-section through the threads (tensile stress area) for M8 × 1.25. D is the diameter: (π/4) × (D − 0.9382 × pitch)²

   $\frac{\text{π}}{4}\times {\left(8-0.9382\times 1.25\right)}^2$$=36.608463\text{\hspace{0.17em}mm²}$

2. Find the proof load, the most the bolt can hold without stretching for good: proof strength × stress area

   $580\text{\hspace{0.17em}MPa}\times 36.608463\text{\hspace{0.17em}mm²}$$=\mathrm{21,232.908448}\text{\hspace{0.17em}N}$

3. Set the clamp load you're aiming for: 60% of the proof load

   $\mathrm{21,232.908448}\text{\hspace{0.17em}N}\times \mathrm{60\%}$$=\mathrm{12,739.745069}\text{\hspace{0.17em}N}$

4. Find the tightening torque T: nut factor K × bolt diameter D × clamp load F

   $0.15\times 8\text{\hspace{0.17em}mm}\times \mathrm{12,739.745069}\text{\hspace{0.17em}N}$$=\mathrm{15,287.694083}\text{\hspace{0.17em}N·mm}$

5. Convert to lbf·in

   $\mathrm{15,287.694083}\text{\hspace{0.17em}N·mm}\times 0.0088507458$$=135.307494\text{\hspace{0.17em}lbf·in}$

7. Estimated tightening torque: 2,948.7 lbf·in

1. Find the bolt's effective cross-section through the threads (tensile stress area) for M16 × 1.5 (fine). D is the diameter: (π/4) × (D − 0.9382 × pitch)²

   $\frac{\text{π}}{4}\times {\left(16-0.9382\times 1.5\right)}^2$$=167.248099\text{\hspace{0.17em}mm²}$

2. Find the proof load, the most the bolt can hold without stretching for good: proof strength × stress area

   $830\text{\hspace{0.17em}MPa}\times 167.248099\text{\hspace{0.17em}mm²}$$=\mathrm{138,815.92208}\text{\hspace{0.17em}N}$

3. Set the clamp load you're aiming for: 75% of the proof load

   $\mathrm{138,815.92208}\text{\hspace{0.17em}N}\times \mathrm{75\%}$$=\mathrm{104,111.94156}\text{\hspace{0.17em}N}$

4. Find the tightening torque T: nut factor K × bolt diameter D × clamp load F

   $0.2\times 16\text{\hspace{0.17em}mm}\times \mathrm{104,111.94156}\text{\hspace{0.17em}N}$$=\mathrm{333,158.212991}\text{\hspace{0.17em}N·mm}$

5. Convert to lbf·in

   $\mathrm{333,158.212991}\text{\hspace{0.17em}N·mm}\times 0.0088507458$$=\mathrm{2,948.698651}\text{\hspace{0.17em}lbf·in}$

8. Estimated tightening torque: 234.87 N·m

1. Convert the clamp load to N

   $\mathrm{11,000}\text{\hspace{0.17em}lbf}\times 4.4482216153$$=\mathrm{48,930.437768}\text{\hspace{0.17em}N}$

2. Find the tightening torque T: nut factor K × bolt diameter D × clamp load F

   $0.2\times 24\text{\hspace{0.17em}mm}\times \mathrm{48,930.437768}\text{\hspace{0.17em}N}$$=\mathrm{234,866.101286}\text{\hspace{0.17em}N·mm}$

3. Convert to N·m

   $\mathrm{234,866.101286}\text{\hspace{0.17em}N·mm}\times 0.001$$=234.866101\text{\hspace{0.17em}N·m}$

9. Estimated tightening torque: 194.68 N·m

1. Find the bolt's effective cross-section through the threads (tensile stress area) for M16 × 1.5 (fine). D is the diameter: (π/4) × (D − 0.9382 × pitch)²

   $\frac{\text{π}}{4}\times {\left(16-0.9382\times 1.5\right)}^2$$=167.248099\text{\hspace{0.17em}mm²}$

2. Find the proof load, the most the bolt can hold without stretching for good: proof strength × stress area

   $970\text{\hspace{0.17em}MPa}\times 167.248099\text{\hspace{0.17em}mm²}$$=\mathrm{162,230.655924}\text{\hspace{0.17em}N}$

3. Set the clamp load you're aiming for: 75% of the proof load

   $\mathrm{162,230.655924}\text{\hspace{0.17em}N}\times \mathrm{75\%}$$=\mathrm{121,672.991943}\text{\hspace{0.17em}N}$

4. Find the tightening torque T: nut factor K × bolt diameter D × clamp load F

   $0.1\times 16\text{\hspace{0.17em}mm}\times \mathrm{121,672.991943}\text{\hspace{0.17em}N}$$=\mathrm{194,676.787109}\text{\hspace{0.17em}N·mm}$

5. Convert to N·m

   $\mathrm{194,676.787109}\text{\hspace{0.17em}N·mm}\times 0.001$$=194.676787\text{\hspace{0.17em}N·m}$

10. Estimated tightening torque: 11.32 lbf·ft

1. Find the bolt's effective cross-section through the threads (tensile stress area) for 5/16-18 UNC. D is the diameter: (π/4) × (D − 0.9743 × pitch)²

   $\frac{\text{π}}{4}\times {\left(0.3125-0.9743\times 0.05555556\right)}^2$$=0.05243\text{\hspace{0.17em}in²}$

2. Find the proof load, the most the bolt can hold without stretching for good: proof strength × stress area

   $\mathrm{85,000}\text{\hspace{0.17em}psi}\times 0.05243\text{\hspace{0.17em}in²}$$=\mathrm{4,456.567083}\text{\hspace{0.17em}lbf}$

3. Set the clamp load you're aiming for: 65% of the proof load

   $\mathrm{4,456.567083}\text{\hspace{0.17em}lbf}\times \mathrm{65\%}$$=\mathrm{2,896.768604}\text{\hspace{0.17em}lbf}$

4. Find the tightening torque T: nut factor K × bolt diameter D × clamp load F

   $0.15\times 0.3125\text{\hspace{0.17em}in}\times \mathrm{2,896.768604}\text{\hspace{0.17em}lbf}$$=135.786028\text{\hspace{0.17em}lbf·in}$

5. Convert to lbf·ft

   $135.786028\text{\hspace{0.17em}lbf·in}\times 0.0833333333$$=11.315502\text{\hspace{0.17em}lbf·ft}$