>>281657527
Ripping out the screw makes no sense, agreed. It would be more believable if his claw stuck to the metal thing.
The claw got magnetized because the coil had current running through it, creating an electromagnet. The magnetic field caused the magnetic domains in the claw to align, leaving magnetizing.
What's more interesting is that he was able to modulate the output of Senku's transmitter by 'fingering' the coil. By shoving his claw into the coil he changed the inductance of the coil causing small variations in the output of the transmitter.