Oil thrower: (it can be omitted) thousands of
Cleaning machine: also thousands of,
Annealing furnace: (it will be 1W, It can be outsourced at first)
Polishing machine: (it can be used with cleaning machine)
Nailing machine: (there are also different manufacturers and models to choose from) ranging from 3W to 6W
Nail washing machine: (or nail roller, deburring) thousands of pieces
Combination machine: at least 3W, at least 3 W. It's also a few W, the cheapest is always 2W, and 1W is good.)
If you know how to do it, there may be some places where you can save money. I've seen a small room, and it's very simple to start making products after breaking down a few machines, so the investment should be very economical.