Why would you tip him? You're already paying for his services directly.
You don't pay your waitress directly. You pay the restaurant for the food, the restaurant pays your waitress about $2-3 per hour. She supplements her wages with tips. It's part of our labor laws, explicitly, regarding minimum wage. Pizza delivery is included in that.
Most of us tip our barber or hairdresser, but in reality, you aren't supposed to tip the shop owner if they are the one that cuts your hair. If someone else cuts your hair, they are paid minimum wage or less, supplemented with tips. They pay a portion of their take to the house, which is where the house makes money. The shop owner is already taking her entire cut for herself, she's not splitting it with the employee and so you don't tip her.
I don't tip my driller since I pay him directly. If he had an assistant who he paid and the assistant drilled my equipment, I might. It hasn't been an option since the guy here works alone.
SH