Can't remember the name of the place exactly but there is a good one at the corner of Oro and Beruti in Palermo. Juan is the owner. I have used his business a few times without problem.
There is a huge locksmith shop on Avenida Santa Fe, going towards Belgrano neigbourhood on the right hand, before the train station. There is also a smaller one on Cabello, almost Ugarteche street. Both places are reliable
