〔 TECHNICAL DATA 〕 TABLE OF DIAMETER OF SCREW LOW HOLE REFERENCE: JIS B 1004 (2009)
〔 TECHNICAL DATA 〕 CORRECT TIGHTENING AXIAL FORCE AND CORRECT TIGHTENING TORQUE FOR BOLTS
1. Meter coarse thread
■ The tightening axial force and fatigue limit when clamping with bolts • The calculation of the correct tightening axial force when tightening the bolts should be within the elastic behavior limit with a maximum of 70% of the standard yield strength under the Torque Method. • The fatigue strength of the bolt from repeated loads should not exceed the allowable value.
Maximum dimensions Grade 2 Grade 3
Maximum dimensions Grade 2 Grade 3
Maximum dimensions Grade 2/Grade 3
Maximum dimensions Grade 2/Grade 3
Nominal size of thread
Nominal size of thread
The Torque Method, the Torque Gradient Method, the Turn–of–Nut Method and the Stretch Measurement Method can all be used as the method of bolt tightening, but the Torque Method is relatively simple and is widely used.
M 1 × 0.25 M 1.1 × 0.25 M 1.2 × 0.25 M 1.4 × 0.3 M 1.6 × 0.35 M 1.7 × 0.35 M 1.8 × 0.35 M 2 × 0.4 M 2.2 × 0.45 M 2.3 × 0.4 M 2.5 × 0.45 M 2.6 × 0.45 M 3 × 0.5 M 3.5 × 0.6 M 4 × 0.7 M 4.5 × 0.75 M 5 × 0.8 M 6 × 1 M 7 × 1 M 8 × 1.25 M 9 × 1.25 M 10 × 1.5 M 11 × 1.5 M 12 × 1.75 M 14 × 2 M 16 × 2 M 18 × 2.5 M 20 × 2.5 M 22 × 2.5 M 24 × 3 M 27 × 3 M 30 × 3.5 M 33 × 3.5 M 36 × 4 M 39 × 4 M 42 × 4.5 M 45 × 4.5 M 48 × 5
M 16 × 1.5 M 16 × 1 M 17 × 1.5 M 17 × 1 M 18 × 2 M 18 × 1.5 M 18 × 1 M 20 × 2 M 20 × 1.5 M 20 × 1 M 22 × 2 M 22 × 1.5 M 22 × 1 M 24 × 2 M 24 × 1.5 M 24 × 1 M 25 × 2 M 25 × 1.5 M 25 × 1
0.73 0.83 0.93 1.08 1.22 1.33 1.42 1.57 1.71 1.87 2.01 2.12 2.46 2.85 3.24 3.69 4.13 4.92 5.92 6.65 7.65 8.38 9.38
0.78 0.89 0.98 1.14 1.32 1.42 1.52 1.67 1.84 1.97 2.14 2.23 2.60 3.01 3.42 3.88 4.33 5.15 6.15 6.91 7.91 8.68 9.68
– – – – – – – – – – – –
14.38 14.92 15.38 15.92 15.84 16.38 16.92 17.84 18.38 18.92 19.84 20.38 20.92 21.84 22.38 22.92 22.84 23.38 23.92
14.68 15.15 15.68 16.15 16.21 16.68 17.15 18.21 18.68 19.15 20.21 20.68 21.15 22.21 22.68 23.15 23.21 23.68 24.15
14.75 15.22 15.75 16.22 16.31 16.75 17.22 18.31 18.75 19.22 20.31 20.75 21.22 22.31 22.75 23.22 23.31 23.75 24.22
• The flange of a bolt or nut should not be sunk into the clamped surface. • The clamped surface should not be damaged through the tightening of bolts. ■ Calculation of the tightening axial force and tightening torque The relationship of the tightening axial force Ff is expressed in formula (1). Ff = 0.7 ×σ y × As …… (1) The tightening torque T fA is calculated by formula (2). T fA = 0.35k (1 + 1/Q) σ y ・ As ・ d …… (2) ■ Calculation Example The correct torque and axial force is required to clamp two pieces of soft steel with a socket head cap screw M6 (strength category of 12.9) in a lubricated state. • The correct torque is shown using formula (2) T fA = 0.35k (1 + 1/Q) σ y ・ As ・ d = 0.35 ・ 0.17 (1 + 1/1.4) 1098 ・ 20.1 ・ 0.6 = 1351 [N ・ cm] {138 [kgf ・ cm]}
k : torque coefficient d : nominal bolt diameter [cm] Q : tightening coefficient σ y : yield strength (1098N/mm 2 {112kgf/mm 2 } when strength category is 12.9) As : effective cross–sectional area of bolt [mm 2 ]
2.64 3.05 3.47 3.92 4.38 5.22 6.22 6.98 7.98 8.75 9.75
M 26 × 1.5
24.38
24.68
24.75
• The axial force Ff is shown using formula (1) Ff = 0.7 ×σ y × As
10.11 11.84 13.84 15.29 17.29 19.29 20.75 23.75 26.21 29.21 31.67 34.67 37.13 40.13 42.59
10.44 12.21 14.21 15.74 17.74 19.74 21.25 24.25 26.77 29.77 32.27 35.27 37.80 40.80 43.30
10.53 12.31 14.31 15.85 17.85 19.85 21.38 24.38 26.92 29.92 32.42 35.42 37.98 40.98 43.49
M 27 × 2 M 27 × 1.5 M 27 × 1 M 28 × 2 M 28 × 1.5 M 28 × 1 M 30 × 3 M 30 × 2 M 30 × 1.5 M 30 × 1 M 32 × 2 M 32 × 1.5 M 33 × 3 M 33 × 2 M 33 × 1.5
24.84 25.38 25.92 25.84 26.38 26.92 26.75 27.84 28.38 28.92 29.84 30.38 29.75 30.84 31.38
25.21 25.68 26.15 26.21 26.68 27.15 27.25 28.21 28.68 29.15 30.21 30.68 30.25 31.21 31.68
25.31 25.75 26.22 26.31 26.75 27.22 27.38 28.31 28.75 29.22 30.31 30.75 30.38 31.31 31.75
= 0.7 × 1098 × 20.1 = 15449 [N] {1576 [kgf]}
■ Torque coefficient depends on combination of the surface treatment of the bolt, the surface to be clamped, and the female thread material. Bolt surface treatment lubricant Torque coefficient k Combining Material of surface to be clamped – Material of female screw (a) (b) （ a ） （ b ）
■ The standard values of tightening coefficient Q Tightening coefficient Q Tightening method Surface state Bolt Nut
Lubrication state
Manganese phosphate
1.25 Torque wrench
0.145 SCM–FC FC–FC SUS–FC 0.155 S10C–FC SCM–S10C SCM–SCM FC–S10C FC–SCM 0.165 SCM–SUS FC–SUS AL–FC SUS–S10C SUS–SCM SUS–SUS 0.175 S10C–S10C S10C–SCM S10C–SUS AL–S10C AL–SCM 0.185 SCM–AL FC–AL AL–SUS 0.195 S10C–AL SUS–AL 0.215 AL–AL
Non–treated or phosphate
Lubricated or MoS 2 paste
Torque wrench
1.4
Non–treated or phosphate
Ratchet wrench 1.6 Impact wrench
Steel bolts Black oxide coating lubricated
Torque wrench Ratchet wrench
2. Meter fine thread
Non–treated or phosphate
1.8
Non–treated not lubricated
Maximum dimensions Grade 2 Grade 3
Maximum dimensions Grade 2/Grade 3
M 35 × 1.5
Nominal size of thread
33.38
33.68
33.75
Expressing strength categories Example 12. 9
M 2.5 × 0.35
M 36 × 3 M 36 × 2 M 36 × 1.5
2.12
2.22
–
32.75 33.84 34.38
33.25 34.21 34.68
33.38 34.31 34.75
Steel bolts Black oxide coating not lubricated 0.25 S10C–FC SCM–FC FC–FC 0.35 S10C–SCM SCM–SCM FC–S10C FC–SCM AL–FC 0.45 S10C–S10C SCM–S10C AL–S10C AL–SCM 0.55 SCM–AL FC–AL AL–AL S10C: Non heat–treated steel SCM: Heat–treated steel (35HRC) FC: Cast iron (FC200) AL: Aluminum SUS: Stainless (SUS304)
Yield strength (yield stress): 90% of the minimum tensile strength The minimal tensile strength is 1220N/mm 2 {124kgf/mm 2 }
M 3 × 0.35 M 3.5 × 0.35 M 4 × 0.5 M 4.5 × 0.5 M 5 × 0.5 M 5.5 × 0.5 M 6 × 0.75 M 7 × 0.75 M 8 × 1 M 8 × 0.75 M 9 × 1 M 9 × 0.75 M 10 × 1.25 M 10 × 1 M 10 × 0.75 M 11 × 1 M 11 × 0.75 M 12 × 1.5 M 12 × 1.25 M 12 × 1 M 14 × 1.5 M 14 × 1 M 15 × 1.5 M 15 × 1
2.62 3.12 3.46 3.96 4.46 4.96 5.19 6.19 6.92 7.19 7.92 8.19 8.65 8.92 9.19
2.72 3.22 3.60 4.10 4.60 5.10 5.38 6.38 7.15 7.38 8.15 8.38 8.91 9.15 9.38
– –
M 38 × 1.5
3.64 4.14 4.64 5.14 5.42 6.42 7.22 7.42 8.22 8.42 8.98 9.22
36.38
36.68
36.75
10. 9
M 39 × 3 M 39 × 2 M 39 × 1.5 M 40 × 3 M 40 × 2 M 40 × 1.5 M 42 × 4 M 42 × 3 M 42 × 2 M 42 × 1.5 M 45 × 4 M 45 × 3 M 45 × 2 M 45 × 1.5 M 48 × 4 M 48 × 3 M 48 × 2 M 48 × 1.5 M 50 × 3 M 50 × 2 M 50 × 1.5
35.75 36.84 37.38 36.75 37.84 38.38 37.67 38.75 39.84 40.38 40.67 41.75 42.84 43.38 43.67 44.75 45.84 46.38 46.75 47.84 48.38
36.25 37.21 37.68 37.25 38.21 38.68 38.27 39.25 40.21 40.68 41.27 42.25 43.21 43.68 44.27 45.25 46.21 46.68 47.25 48.21 48.68
36.38 37.31 37.75 37.38 38.31 38.75 38.42 39.38 40.31 40.75 41.42 42.38 43.31 43.75 44.42 45.38 46.31 46.75 47.38 48.31 48.75
Yield strength (yield stress): 90% of the minimum tensile strength The minimal tensile strength is 1040N/mm 2 {106kgf/mm 2 }
■ Initial tightening strength and torque
Strength category
Effective cross– sectional area As mm 2
Nominal size of thread
12.9 8.8 Yield load Initial tightening strength Tightening torque Yield load Initial tightening strength Tightening torque Yield load Initial tightening strength Tightening torque N {kgf} N {kgf} N ・ cm {kgf ・ cm} N {kgf} N {kgf} N ・ cm {kgf ・ cm} N {kgf} N {kgf} N ・ cm {kgf ・ cm} 10.9
M3 × 0.5 M4 × 0.7 M5 × 0.8 M6 × 1 M8 × 1.25 M10 × 1.5 M12 × 1.75 M14 × 2 M16 × 2 M18 × 2.5 M20 × 2.5 M22 × 2.5 M24 × 3
5.03 8.78
5517 { 9633 {
563 } 983 }
3861 { 6742 {
394 } 688 }
167 { 392 { 794 {
17 } 40 }
4724 { 8252 {
482 } 842 }
3312 { 5772 { 9339 {
338 } 589 } 953 }
147 { 333 { 676 {
15 } 34 } 69 }
3214 { 5615 { 9085 {
328 } 573 } 927 }
2254 { 3930 { 6360 { 9006 {
230 } 401 } 649 } 919 }
98 {
10 } 23 } 47 } 80 }
225 { 461 { 784 {
14.2 20.1 36.6
15582 { 22060 { 40170 { 63661 { 92532 {
1590 } 10907 { 2251 } 15445 { 4099 } 28116 { 6496 } 44561 { 9442 } 64768 {
1113 } 1576 } 2869 } 4547 }
81 } 13348 { 138 } 18894 { 334 } 34398 { 663 } 54508 { 1160 } 79223 {
1362 }
–
1352 { 3273 { 6497 {
1928 } 13220 { 3510 } 24079 { 5562 } 38161 { 8084 } 55458 {
1349 } 2457 } 3894 } 5659 }
1156 { 2803 { 5557 { 9702 {
118 } 12867 { 286 } 23422 { 567 } 37113 { 990 } 53949 { 1580 } 73598 {
1313 }
2390 } 16395 { 3787 } 25980 { 5505 } 37759 { 7510 } 51519 {
1673 } 2651 } 3853 }
1911 { 3783 { 6605 {
195 } 386 } 674 }
9.92
10.15 10.38 10.68 10.91 11.15 12.68 13.15 13.68 14.15
10.22 10.42 10.75 10.98 11.22 12.75 13.22 13.75 14.22
58
10.19
84.3
6609 } 11368 { 9016 } 18032 {
10.38 10.65 10.92 12.38 12.92 13.38 13.92
115 157 192 245 303 353
126224 { 12880 } 88357 {
1840 } 108084 { 11029 } 75656 {
7720 } 15484 {
5257 } 10486 { 7176 } 16366 { 9045 } 23226 {
1070 } 1670 } 2370 } 3360 } 4580 } 5820 }
172323 { 17584 } 117982 { 12039 } 28126 { 210739 { 21504 } 147519 { 15053 } 38710 { 268912 { 27440 } 188238 { 19208 } 54880 { 332573 { 33936 } 232799 { 23755 } 74676 { 387453 { 39536 } 271215 { 27675 } 94864 {
2870 } 147549 { 15056 } 103282 { 10539 } 24108 { 3950 } 180447 { 18413 } 126312 { 12889 } 33124 { 5600 } 230261 { 23496 } 161181 { 16447 } 46942 { 7620 } 284768 { 29058 } 199332 { 20340 } 63896 { 9680 } 331759 { 33853 } 232231 { 23697 } 81242 {
2460 } 100470 { 10252 } 70325 { 3380 } 126636 { 12922 } 88641 {
4790 } 161592 { 16489 } 113112 { 11542 } 32928 { 6520 } 199842 { 20392 } 139885 { 14274 } 44884 { 8290 } 232819 { 23757 } 162974 { 16630 } 57036 {
(Notes) • Tightening conditions: The use of a torque wrench (surface lubrication, torque coefficient k = 0.17, tightening coefficient Q = 1.4) • The torque coefficient changes depending on conditions of use, so please use this table as a rough estimate only. • This table is an edited excerpt from a catalogue from KYOKUTO MFG. Co., Ltd.
1225
1226
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