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Tightening Torque and Forces for Bumax Joints

Tightening Torques and Force for Metric Bumax Joints
Thread Size and Class Class M3 M4 M5 M6 M8 M10 M12 M14
Tightening Torque Mv in Nm (1) (3) Bumax 109 1.7 4.1 8.1 14 34 66 115 162
  Bumax 88 1.3 2.9 5.7 10 25 47 82 129
  Bumax Lock     6.6 12 29 54 94  
Preload Applied +/- 23% (2) Bumax 109 2.9 5.2 8.6 12 21 34 49 60
  Bumax 88 2.1 3.6 5.9 8.4 15 24 35 48
  Bumax Lock       8.4 15 24 35  
Failure Load KN Bumax 109 5 8.8 14 20 37 58 84 115
  Bumax 88 4 7 11 16 29 46 67 92
  Bumax Lock     11 16 29 46 67  
Yield Load KN Bumax 109 4.5 8 12 18 33 52 76 92
  Bumax 88 3.2 6 9 13 23 37 54 74
  Bumax Lock     9 13 23 37 54  
Nominal Stress area mm2   5.03 8.78 14.2 20.1 36.6 58.0 84.3 115
Pitch of thread   0.5 0.7 0.8 1.0 1.25 1.5 1.75 2.0
Tightening Torques and Force for Metric Bumax Joints
Thread Size and Class Class M16 M18 M20 M24 M27 M30 M36
Tightening Torque Mv in Nm (1) (3) Bumax 109 248 275 481        
  Bumax 88 198 275 385 665 961 1310 2280
  Bumax Lock 228   442 765      
Preload Applied +/- 23% (2) Bumax 109 81 100 128        
  Bumax 88 65 80 102 181 235 287 418
  Bumax Lock 65   102 181      
Failure Load KN Bumax 109 157 192 245        
  Bumax 88 126 154 196 282 367 449 654
  Bumax Lock 126   196 282      
Yield Load KN Bumax 109 125 154 196        
  Bumax 88 100 123 157 226 294 359 523
  Bumax Lock 100   157 226      
Nominal Stress area mm2   157 192 245 353 459 561 817
Pitch of thread   2.0 2.5 2.5 3.0 3.0 3.5 4.0
Tightening Torque and Force for Imperial Bumax Joints
Thread Size and Class Class 1/4-20 UNC 5/16-18 UNC 3/8-16 UNC 1/2-13 UNC 5/8-11 UNC 3/4-10 UNC 7/8-9 UNC 1"-8 UNC
Tightening Torque Mv in Nm (1) (3) Bumax 88 11 22 39 95 188 329 527 789
Preload Applied KN +/- 23% (2) Bumax 88 8.7 14.3 21.1 38.7 61.7 91.2 125.9 165.2
Failure Load KN Bumax 88 17 28 41.5 75.9 121 179 247 325
Yield Load KN Bumax 88 13.1 22.4 33.2 60.8 96.9 143.4 197.9 259.6
Nominal Stress Area mm2 Bumax 88 20.5 33.8 50.0 91.5 146 216 298 391

(1) The Mv recommendations refer to burr-free surfaces lubricated with a good quality lubricant. (2) The preload applied is calculated as 65% of Rp 0.2 but in practise the value can be expected to vary between 50 -80%. (3) The Mv-recommendations are calculated assuming a coefficient of friction of 0.16 which requires a good-quality lubricant.