Enlarging bulkhead hole

[Doug]

Can you enlarge a 1 1/8th drilled hole to 1 3/4, so they can take a 1in bulkheads?

I cant even get a 3/4in bulkhead in there, as I planned on. Even that takes a 1 1/2 in or 1 7/16in. hole. Only other option is to go with 1/2in and then enlarge stacks to 1in. but still a 1/2 in drain. I would then have two 1/2in drains and a 1in main drain for my bean