I bought a 53 inch long .7500 gun drill. I cut it in half and made an adapter. The adapter has a 1/2 inch shank and a 3/4 in hole. It is attached to the drill shank with a 1/4-20 set screw and has an air fitting installed in it. It is simply sealed up with 5 minute epoxy..
It cost $20.................
Kim

]

It cost $20.................
Kim

]