Tightening Torques and Force for Metric Bumax Joints

Thread Size and Class

Class

M3

M4

M5

M6

M8

M10

M12

M14

M16

M18

M20

M24

M27

M30

M36

Tightening Torque Mv in Nm (1) (3)

Bumax 109

1.7

4.1

8.1

14

34

66

115

162

248

275

481

Bumax 88

1.3

2.9

5.7

10

25

47

82

129

198

275

385

665

961

1310

2280

Bumax Lock

6.6

12

29

54

94

228

442

765

Preload Applied +/- 23% (2)

Bumax 109

2.9

5.2

8.6

12

21

34

49

60

81

100

128

Bumax 88

2.1

3.6

5.9

8.4

15

24

35

48

65

80

102

181

235

287

418

Bumax Lock

8.4

15

24

35

65

102

181

Failure Load KN

Bumax 109

5

8.8

14

20

37

58

84

115

157

192

245

Bumax 88

4

7

11

16

29

46

67

92

126

154

196

282

367

449

654

Bumax Lock

11

16

29

46

67

126

196

282

Yield Load KN

Bumax 109

4.5

8

12

18

33

52

76

92

125

154

196

Bumax 88

3.2

6

9

13

23

37

54

74

100

123

157

226

294

359

523

Bumax Lock

9

13

23

37

54

100

157

226

Nominal Stress area mm2

5.03

8.78

14.2

20.1

36.6

58.0

84.3

115

157

192

245

353

459

561

817

Pitch of thread

0.5

0.7

0.8

1.0

1.25

1.5

1.75

2.0

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.