/diy/ - Do It Yourself

What does the ring around the post on a drill press do/is it important?
My dad bought an old one for hella cheap but didn't notice that the ring is broken where the threaded hole is.
Every drill press seems to have one but in the short time I spent poking at it in the dark I couldn't see any evidence that it actually did anything.
Didn't get a picture, so I've illustrated the concept.