It looks more like an electric version of an air chisel. HERE
is a cutter for one. Note the flange to the left of the blue label. You remove the collar, slide the left side of the chisel through it making sure the flange is inside the collar, then reattach the collar and bit to the body of the tool. As long as you maintain pressure on the chisel while the trigger is pulled the chisel should stay where you want it. These days they have OSHA approved safety chucks that would hold the cutter bit in place with or without pressure on the bit. HERE
is an air chisel set.
EDIT > Oops. Never mind. I just saw the hex opening behind the collar. Screw gun.