This is a late reply, but personally I don't believe it's the line tool. If you look closely at some parts, there are little errors, "bent lines" that aren't as narrow as the line tool would draw them. I think you can see it pretty well at two little plates at the bottom.
He's drawing a lot of good mechs and he's doing it well, I figure he's just got insane experience with this style - and naturally the exact lines that are used everywhere.
Haha, no problem at all. Yes, practice is indeed a powerful asset. Every time demonstrated when I find some pretty high-quality art on dA and the comments say the artist just doodled on their new tablet for an hour to get a first grasp for it.