One gear is the only line worth talking about. The metal fragments are a single furnace load, and the blueprint is about as cheap as Level 1 gets. But gears only become a craft at Level 3, where each costs 100 scrap, so early on every hopper is a gear you found on a road run.
That gear has better homes. Two of them make a garage door, and a door on the loot room protects more than a tidy drop room does. So the hopper waits until the doors are hung.
Learn the industrial conveyor in the same research run: a hopper with nothing pulling from it just fills up.
