Screw Forces and TorqueRuuvivoimat ja kiristysmomenttiMetric standard thread 640 N/mm2 = Material 0,2 -limit 0,15 µ = Friction factor of the thread 0,15 µ = Friction factor of the nut 60ŗ = Flank angle of the thread 0,4 - 0,5 - 0,63 - 0,8 - 1 - 1,25 - 1,6 - 2,0M4 - M5 - M6 - M8 - M10 - M12 - M16 - M20 _______________________________________________________________ Tensile tress Clamping force Needed tighteningmax. max. torqueN / mm2 N Calculation Nm Calculation M4 559,36 4911 Given value 2,6 Given value M5* 562,61 7989 1,618 x 4911= 7946 5,0 21 x 2,6 = 5,2 M6** 561,22 11280 1,6182 x 4911= 12857 8,6 22 x 2,6 = 10,4 M8 563,34 20618 1,6183 x 4911= 20802 20,7 23 x 2,6 = 20,8 M10 564,52 32742 1,6184 x 4911= 33658 40,2 24 x 2,6 = 41,6 M12*** 565,26 47652 1,6185 x 4911= 54458 68,3 25 x 2,6 = 83,2 M16 568,52 89257 1,6186 x 4911= 88113 165,0 26 x 2,6 = 166,4 M20 568,52 139286 1,6187 x 4911= 142567 322,5 27 x 2,6 = 332,8 M24 568,52 200686 1,6188 x 4911= 230674 554,6 28 x 2,6 = 665,6 * Fibonacci Numbers start 1 - 1 - 2 ... Pascal's Triangle has the same form. The second is twice the smallest 1 + 1 = 2 2.6 x 2 = 5,0 (not decimal accuracy) ** On the ratio queue, the screw size is M6.3 (0.5 - 0.6.3 - 0.8), which is not the case. This can convert to M6 screw by simplified calculation. (6/6,3)4 x 12857 = 10577 (6/6,3)5 x10,4 = 8,2 (24/25)4 x 230674 = 195922 (24/25)5 x 665,6 = 542,7 2 x surface area = 4 2 x surface area + moment = 5 *** On the ratio queue, the screw size is M12.5 (0.8 - 1 - 1.25 - 16), which is not the case. (12/12,5)4 x 54458 = 46254 (12/12,5)5 x 83,2 = 67,8 3.1 Example:M16 screw clamping force according to the table is 89257 N. Wanted M16 bolt clamping force is 25 % lower, in other words 89 257 N /1.25 = 714 056 N => Tightening torque = 165 Nm /1.25 = 132 Nm 27.10.2011*15:20 (390 - |