Siemens 1MB115 Installation And Maintenance Manual page 141

Tightening torques
The bolted connections with metal contact surfaces, such as end shields,
bearing cartridge parts, terminal box parts bolted onto the stator frame,
should be tightened to the following torques, depending on the thread size:
Table B-1 Tightening torques for bolted connections with a tolerance of
± 10 %.
Thread ∅ M5 M6 M8 M10 M12 M16 M20
Nm 5 8 20 40 70 170 340
The tightening torques stated above apply to bolts with property class 8.8,
A4-70 or A4-80 according to ISO 898-1, however only to bolts screwed into
components made from materials with higher property class, e.g. cast iron,
steel or cast steel.
Non-standard tightening torques
Different tightening torques for electrical connections and bolted connections
for s or insulating parts are specified in the relevant sections and drawings.
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