Stalker's bolt. Every time I watch one of his videos I learn something new. I knew you could make a bolt in a lathe (I've done it) and just mill the head of the bolt, but I love how he reverses it and makes the bolt in the mill then uses the lathe to cut the head. I especially like the format of this videos, I can learn without having to hear him speak (and considering I don't speak Russian it's better this way...)