Eltorque QT250, User Manual, Page: 87 / 92

User Manual QT250 and QT800 gen 2.5, ID 2021 2.3 20. April 2021 Page 87 of 92
The following table lists recommended torque values and minimum thread
engagement when mounting the Eltorque actuators.
Table 25: Screw torque
Thread
size Tightening
torque.
(Nm) Min. thread
engagement.
(mm/in.)
M4 3.4 NA
M5 5.1 7.5/0.30
M6 8.9 9/0.35
M8 21.1 12/0.47
M10 41.5 15/0.59
M12 70.7 18/0.70
M16 172.6 24/0.94
M20 336.2 30/1.18
•
Use A4-80 screw material and quality.
• Use a washer between the bolt head and the mounting flange. Requirements:
DIN 125A, minimum 200HV, A4.
•
Lubricate washer surface and underside of the bolt head with a lubricant
resulting in a friction coefficient 0.08 to 0.14 between bolt head and washer.
The lubricant must
not contain aluminum, zinc or copper. To prevent galling
when using stainless steel fasteners, a lubricant containing MoS
2
is
recommended.
• Use thread lock Loctite 222 or similar, on bolt threads. Be sure that the
amount applied is enough, so no water can get into thread holes after the
bolt is inserted. The thread-
lock’s main purpose in this applicat ion is to
serve as a barrier, preventing seawater to act as a catalyst between bolts and
threads in the actuator base.