TK
+
ATEX
Appendix
Revision: 05
2022-D034859
en-31
10.4.2 Impermissible operating conditions
10.5
Tightening torques for common thread sizes in general mechanical engineering
The specified tightening torques for set screws and nuts are calculated values and are based on
the following conditions:
- Calculation in accordance with VDI 2230 (February 2003 version)
- Friction value for thread and contact surfaces µ=0.10
- Utilization of the yield stress 90%
- Torque tools type II classes A and D in accordance with ISO 6789
The settings are values rounded to usual commercial scale gradations or setting possibilities.
Use the
exact
values in this table to set your tools.
The following operating conditions are not permitted:
- Mounting position B5/V1 (output shaft horizontal, motor shaft
downwards)
- Lateral forces or bending torques acting on the blind hollow shaft /
hollow shaft / hollow shaft interface. If necessary, install external
bearing points for the load shaft. In case of unclear installation
situations, contact
WITTENSTEIN alpha GmbH
.
- Co-riding the gearbox on the drive axle is prohibited. Exceptions
require a written approval and technical statement from
WITTENSTEIN alpha GmbH
.
- Use in continuous duty (S1 duty: power-on time greater than 60% or
longer than 20 minutes)
Tightening torque [Nm] with thread
Property
class
screw / nut
M3
M4
M5
M6
M8 M10 M12 M14 M16 M18 M20 M22 M24
8.8 / 8
1.15 2.64 5.2
9.0 21.5 42.5 73.5 118 180 258 362 495
625
10.9 / 10
1.68 3.88 7.6 13.2 32.0 62.5 108 173 264 368 520 700
890
12.9 / 12
1.97 4.55 9.0 15.4 37.5 73.5 126 202 310 430 605 820 1040
Tbl-20: Tightening torques for set screws and nuts
