In this usage, a cordwainer is someone who makes new shoes using new leather, whereas a cobbler is someone who repairs shoes.

Why are they called cobblers?

Today, most shoes are made on a volume basis, rather than a craft basis. ... The term cobbler was originally used pejoratively to indicate that someone did not know their craft; in the 18th century it became a term for those who repaired shoes but did not know enough to make them.

What does a cordwainer do?

noun Archaic. a person who makes shoes from cordovan leather. shoemaker; cobbler.