My player has a Techmarine with a Servo-Arm, but I can't find statistics for it or what kind of action it takes to use in combat.
In the talent description of Mechadendrite Use on page 123 it states:
Servo-Arm: Servo-arms are powerful mechanical arms fitted with piston-driven claws that are equally effective as weapons as they are at repairing machines.
I haven't been able to find weapon stats for a servo-arm in the rule book though. Where are they listed?
Also, if my player's Techmarine does want to use the servo-arm as a weapon, is that a standard attack or can he use it additionally to his standard attack? What kind of action would it be? A half action or maybe even a free action, as the character only has to spare a thought to move the arm?
I have found the entry in the rule book myself.
Page 177 of the Core Rule book: