Drilling ceramic pots

Hi everyone, my neighbour has kindly given me some ceramic pots this morning, four have good drainage holes but the largest just has one tiny hole, I've read it's masonary bit for unglazed and tile bit for glazed, just wondering what the best size bit is? And what are the odds of breaking it while drilling? Thanks

 

Could try the size of the drill by the one hole that's there already. Don't know about the pot cracking. I know with tiles it's a good idea to put some tape on first.

 

Thanks @Logan & @wiseowl

 

You're welcome, anytime.