Barneys is located on 6th between 10th and 11th and is hard to miss if you walk by quickly.
The store is narrow and small but filled with everything one might need to fix minor repairs/adjustments in a city apartment.
This is no home depot but the service is personalized and friendly. As soon as you walk in, they make an effort to help you. And guess what? If they don't have what you're looking for, they will recommend you go elsewhere (surprising).
All in all, if you live in the west village and can't borrow a screwdriver from a neighbor, then this is a quick fix nearby.