In the first chapter of Mary Poppins, Mr.Banks worked at a bank in the City. 

Quote:

 and while he was there he sat on a large chair in front of a large desk and made money. All day long he worked, cutting out pennies and shillings and half-crowns and threepenny-bits. And he brought them home with him in his little black bag.

Question:

What does cut out mean in the context? Was he involved in manufacturing coins? but then why he sat on a large chair in front of a large desk at work? And even if he did work as a coin manufacturer, how come he could bring some of the coins back home? Shouldn't all the coins belong to the bank?