Why does Herbert give Pip a nickname & what is it?

Herbert doesn't like the name Phillip because it doesn'y match Pip's demeanor. So, he chooses to give him another.

We are so harmonious, and you have been a blacksmith,—-would you mind it?”
“I shouldn’t mind anything that you propose,” I answered, “but I don’t understand you.”
“Would you mind Handel for a familiar name? There’s a charming piece of music by Handel, called the Harmonious Blacksmith.”