Yes, they break locks, people. They can be your best friend and your worst enemy, and can determine the outcome of a battle.
They cost 215 grams of steel to make, and require an anvil in the area you're working in, as well as a hammer in your character's inventory. An anvil has to be built inside, so you'll need to have access to a building.
To break a lock, you simply try to enter into a locked building, and proceed with the picking project. For those that want to help you, they will have to join the picking project initiated by you (provided, of course, that they also have a crowbar). This project has a random outcome. Sometimes you break open a lock first try, and other times you are at it for days at end. Each try takes one person about a day.