bolthole (plural boltholes) A hole in an animal's den, or through a wall or fence, used for escape or emergency exit; i.e. a hole the animal may bolt through.

How much bigger should a hole be than a bolt?

Select a drill bit 1/32 inch larger than the bolt diameter for a tight fit hole or a drill bit 1/16 inch greater than the bolt diameter for a loose fitting hole.

What does a bolthole mean?

chiefly British. : a place of escape or refuge.