I think there should be 2 ways of making it.
You gather the materials and go to a sewing factory, which is a legal area and you can make all the vest that are not level 3 armor.
-- the other method is you can make it at the black market, which will allow you to make all vests + level 3 armor, but it is an illegal area.
Similar to crank, you should be able to buy a portal sewing station that will allow you to make it in your home, which will take up a crate slot, or in an RV.
Just a thought, idk.