Found this in a local semi truck service shop that closed down.

It has a Milwaukee holehawg drill motor.
It has a drill bit guide that's for a 7/16 drill bit, it has a 12" and a 18" bit with it.
This is threaded for a 2 1/2" pipe looks like a finer thread to me.

Any ideas?
I can get more pics if anyone what's them
Feel free to cross post this to other sites, I'd like to know what its used for before I strip it apart for the motor