From the constant cuts to extreme close-up, I'm betting he puts on the tie and collared shirt for talking-to-the-camera shots (and one or two per episode where

From the constant cuts to extreme close-up, I'm betting he puts on the tie and collared shirt for talking-to-the-camera shots (and one or two per episode where a machining tool is on, but he's carefully away from it) and takes it off most of the time when he's actually working.