Metric Bolt Torque

Tightening torque table
Tightening torque table

 

The tightening torque is the force used to tighten the metric fasteners during assembly with a tool. This torque is transmitted to the metric fasteners using an adjustable, suitable torque wrench. The corresponding values for the various screw sizes and strength classes for metric coarse threads can be found in the metric torque table below.

The following table shows the tightening torque for metric thread fasteners. In the List metric bolt torque chart you find the metric torque unit in Nm and ft lbs. You can also made an conversion from the unit Nm to ft lbs and also from ft lbs to Nm. Please find all technical information in the following metric bolt torque chart.

 

 

 

 

5.6 Strehngth class - Aluminium screws

6.8 Strehngth class - V2A screws

8.8 Strehngth class - Titanium screws

 

 

Metric Bolt Torque Chart

In the following table of torque specifications, you will find all the necessary torque values in Newton-meters (Nm) for common screw thread sizes and strength classes. Please note that the required torque may vary due to differences in screw strength classes and thread sizes.

 

   

Recommended mertic metric bolt torque

tightening torque (Nm)

tightening torque (ft lbs)

Metric Thread size

 

Metric Strength class

Torque Unit

4.6 5.6 6.8 8.8 10.9 12.9
 M2 Nm 0,13 0,16 0,26 0,35 0,49 0,59
ft lbs 0,10 0,12 0,19 0,26 0,36 0,44
M2,5 Nm 0,27 0,34 0,54 0,72 1,01 1,21
ft lbs 0,20 0,25 0,40 0,53 0,74 0,89
M3 Nm 0,48 0,60 0,96 1,28 1,80 2,16
ft lbs 0,35 0,44 0,71 0,94 1,33 1,59
M4 Nm 1,12 1,39 2,23 2,97 4,18 5,02
ft lbs 0,83 1,03 1,64 2,19 3,08 3,70
M5 Nm

2,26

2,83 4,52 6,03 8,48 10,18
ft lbs 1,67 2,09 3,33 4,45 6,25 7,51
M6 Nm 3,84 4,80 7,69 10,25 14,41 17,29
ft lbs 2,83 3,54 5,67 7,56 10,63 12,75
M7 Nm 5,13 6,42 10,27 13,70 19,25 23,10
ft lbs 3,78 4,74 7,57 10,10 14,20 17,04
M8 Nm 9,35 11,69  18,70 24,93 35,06 42,07
ft lbs 6,90 8,62 13,79 18,39 25,86 31,03
M10 Nm 18 23 37 49 70 83
ft lbs 13 17 27 36 52 61
M12 Nm 32 40 65 86 121 146
ft lbs 24 30 48 63 89 108
M14 Nm 52 65  104 138 194 233
ft lbs 38 48 77 102 143 172
M16 Nm 81 101  161 215 302 363
ft lbs 60 74 119 159 223 268
M18 Nm  112 139  222 296 417 500
ft lbs 83 103 164 218 308 369
M20 Nm  157 197  315 420 590 709
ft lbs 116 145 232 310 435 523
M22 Nm  215 269  430 574 807 968
ft lbs 159 198 317 423 595 714
M24 Nm  272 340  544 726 1020 1224
ft lbs 201 251 401 535 752 903
M27 Nm  400 500  800 1067 1500 1800
ft lbs 295 369 590 787 1106 1328
M30 Nm  542 677 1083 1445 2032 2438
ft lbs 400 499 799 1066 1499 1798
M33 Nm  739 923 1477 1969 2770 3323
ft lbs 545 681 1089 1452 2043 2451
M36 Nm  948  1185 1896 2528 3555 4266
ft lbs 699 874 1398 1865 2622 3146
M39 Nm 1229  1536 2457 3276 4607 5529
ft lbs 906 1133 1812 2416 3398 4078
M42 Nm 1519  1899 3038 4050 5696 6835
ft lbs 1120 1401 2241 2987 4201 5041
M45 Nm 1898  2373 3796 5062 7118 8541
ft lbs 1400 1750 2800 3734 5250 6299
M48 Nm 2282  2853 4565 6086 8559 10271
ft lbs 1683 2104 3367 4489 6313 7575
M52 Nm 2954  3692 5907 7876 11076 13292
ft lbs 2179 2723 4357 5809 8169 9804
M56 Nm 3672  4591 7345 9793 13772 16526
ft lbs 2708 3386 5417 7223 10158 12189
M60 Nm 4582  5728 9164 12219 17183 20619
ft lbs 3379 4225 6759 9012 12673 15208
M64 Nm 5536  6920 11071 14762 20759 24911
ft lbs 4083 5104 8166 10888 15311 18373
M68 Nm 6720  8400 13440 17919 25199  30239
ft lbs 4956 6196 9913 13216 18586 22303

* All information without guarantee.

What is torque?

Torque is a physical quantity that describes the strength of the rotational force applied to an object.

 

Torque - Unit

The unit for torque M is obtained by multiplying the unit Newton for force F by the unit meter for the lever arm r.

 

[M] = 1 Nm

 

Hence, the unit is called Newton-meter.

 

Formula for Screw Torque (Torque Calculation)

Torque M is obtained by multiplying the force F, which acts perpendicular to a lever arm, by the length r of the lever arm.

 

[M] = F ⋅ r

 

Example: 1 Nm (Newton-meter)

Torque is measured in Newton-meters (Nm). 1 Nm is equivalent to when a force of 1 Newton is applied with a lever arm of 1 meter, resulting in 100 grams of force.

 

Strength classes of screws

 

Screws are marked with different strength classes so that it is very easy to determine the tensile

strength (Rm) and the yield strength (Re).

 

Example: Tensile strength class 5.6

 

1. Determination of Rm:

Multiply the first number by 100 to obtain the tensile strength (Rm).

=> Rm = 5 x 100 = 500 N/mm²

 

2. Determination of Re:

The first number is multiplied by the second number and the result is

multiplied by 10 gives the yield strength (Re).

=> Re = ( 5 x 6 ) x 10 = 300 N/mm²

 

   Strength classes of screws
4.6 5.6 6.8 8.8 10.9 12.9
Tensile strength (Rm) 400 500 600 800 1000 1200
Yield strength (Re) 240 300 480 640 900 1080

* All information without guarantee.

Preload forces for screw connections

 

In a screw connection, two or more parts are joined together. The preload force is the force exerted by a screw or screw connection on the components. If the preload force is high enough and the screw connection is selected correctly, the screwed parts behave like one part and are therefore firmly connected.

 

Preload forces for regular threads

 

Preload force Table for regular threads

Preload force in (N)

Thread size

Strength classes

4.6 5.6 6.8 8.8 10.9 12.9
 M2 338 422 675 901 1267 1520
M2,5 563 703 1125 1500 2110 2532
M3 845 1056 1689 2253 3168 3801
M4 1463 1829 2927 3902 5487 6585
M5 2395 2994 4790 6387 8982 10778
M6 3379 4224 6758 9011 12671 15205
M8 6202 7753 12404 16539 23258 27909
M10 9876 12345 19752 26336 37034 44441
M12 14400 18000 28801 38401 54001 64801
M14 19775 24719 39551 52734 74158 88989
M16 27221 34027 54443 72591 102080 122497
M18 33078 41347 66155 88207 124041 148850
M20 42534 53167 85067 113423 159501 191401
M22 53175 66469 106350 141800 199406 239288
M24 61248 76560 122497 163329 229681 275617
M27 80670 100837 161339 215119 302512 363014
M30 98027 122533 196054 261405 367600 441120
M33 122241 152801 244482 325976 458404 550084
M36 143413 179266 286826 382434 537798 645358
M39 172420 215525 344839 459786 646574 775888
M42 197407 246758 394813 526417 740275 888329
M45 231206 289007 462412 616549 867022  1040426
M48 280008 325010 520015 693354 975029 1170035
M52 312056 390070 624112 832149 1170209 1404251
M56 359643 449804 719689 959581 1349411 1619293
M60 420651 525813 841301 1121735 1577440 1892928
M64 475860 594825 951720 1268960 1784476 2141371
M68 545427 681784 1090855 1454473 2045353 2454423

* All information without guarantee.

FAQ - Frequently Asked Questions

When does a screw break?

A screw can break when the allowable yield point is exceeded, causing it to deform and ultimately leading to the screw breaking.

 

What can happen if the torque is too high?

Excessive torque can damage threads and components, leading to malfunctions and safety risks. Therefore, proper torque application is crucial.

 

How tight should you tighten wheel nuts?

The recommended torque for wheel nuts of a vehicle can be found in the vehicle's manual and is typically between 80 and 160 Newton-meters.

 

How much Nm is hand-tight?

Hand-tight typically corresponds to a torque of approximately 30 Newton-meters (Nm) when manually applied with a standard screwdriver or similar tool.

 

Where can you find torque specifications?

Torque specifications for screws and components are usually available in the manufacturer's documentation or the vehicle's manuals. If you cannot find them there, you can look up the corresponding torque for the screw in a torque specification table.