Torque-Tension Relationship for Metric Fasteners
Class 4.6
Class 8.8
Nominal
Dia.
Pitch
(mm)
Clamp
Clamp
Tightening Torque
Tightening Torque
Load Lubricated Zinc Plated Plain&Dry Load Lubricated Zinc Plated Plain&Dry
(lbs)
(ft-lbs)
(ft-lbs)
(ft-lbs)
(lbs)
(ft-lbs)
(ft-lbs)
(ft-lbs)
4
0.7
333
0.7
0.7
0.9
858
1.7
1.9
2.3
5
0.8
538
1.3
1.5
1.8
1387
3.4
3.9
4.5
6
1
763
2.3
2.6
3.0
1968
5.8
6.6
7.7
7
1
1095
3.8
4.3
5.0
2822
9.7
11.0
13.0
8
1.25 1389
5.5
6.2
7.3
3580
14.1
16.0
18.8
10
1.5
2200
10.8
12.3
14.4
5671
27.9
31.6
37.2
12
14
16
18
20
22
24
27
30
33
36
1.75
2
2
2.5
2.5
2.5
3
3
3.5
3.5
4
3197
4379
5943
7301
9286
11509
13372
17428
21266
26310
30982
18.9
30.2
47
65
91
125
158
232
314
427
549
21.4
34.2
53
73
104
141
179
262
356
484
622
25.2
40.2
62
86
122
166
211
309
419
570
732
8240
11289
15320
18822
23938
29669
34471
44924
54819
67821
79866
48.7
77.8
121
167
236
321
407
597
809
1101
1415
55.1
88.1
137
189
267
364
461
676
917
1248
1603
64.9
103.7
161
222
314
428
543
796
1079
1468
1886
Class 10.9
C lamp
Load
(lbs)
1228
1985
2816
4039
5123
8115
11792
16154
21924
26934
34256
42457
49329
64288
78448
97055
114291
Class 12.9
Tightening Torque
Lubricated Zinc Plated Plain&Dry
(ft-lbs)
(ft-lbs)
(ft-lbs)
2.4
2.7
3.2
4.9
5.5
6.5
8.3
9.4
11.1
13.9
15.8
18.5
20.2
22.9
26.9
39.9
45.2
53.2
69.6
111.3
173
239
337
460
582
854
1158
1576
2024
78.9
126.1
196
270
382
521
660
968
1312
1786
2294
92.8
148.4
230
318
449
613
777
1139
1544
2101
2699
Clamp
Load
(lbs)
1436
2319
3291
4720
5987
9484
13781
18879
25622
31477
40034
49619
57649
75132
91680
113425
133569
Tightening Torque
Lubricated As-Received Plain&Dry
(ft-lbs)
(ft-lbs)
(ft-lbs)
2.8
3.2
3.8
5.7
6.5
7.6
9.7
11.0
13.0
16.3
18.4
21.7
23.6
26.7
31.4
46.7
52.9
62.2
81.4
130.0
202
279
394
537
681
998
1353
1842
2366
92.2
147.4
229
316
446
609
771
1131
1534
2087
2681
The torque values can only be achieved if nut (or tapped hole) has a proof load greater than or equal to the bolt's minimum ultimate tensile strength.
Clamp loads estimated as 75% of proof load for specified bolts.
Torque values listed in foot-pounds .
Torque values calculated from formula T=KDF where; K=0.15 for "lubricated" condition, K=0.17 for zinc plated and dry condition (or as-received for the 12.9), K=0.20 for plain and dry
condition
Caution: All material included in this chart is advisory only, and its use by anyone is voluntary. In developing this information, Fastenal has made a determined effort
to present its contents accurately. Extreme caution should be used when using a formula for torque/tension relationships. Torque is only an indirect indication of
tension. Under/over tightening of fasteners can result in costly equipment failure or personal injury.
Rev 3-4-09
108.5
173.4
269
372
525
716
908
1331
1804
2455
3154