hey guys I dont feel like paying 60$ for a peice of copper pipe and a drill bit... SO i was wondering if anyone knew what size drill bit/copper bushing they use? I will probably go pull my qjet off of my camaro in storage and have a hay day at the local hardware store.

 

It's a thin wall copper bushing. I think it's a 5/16".
It might be a bronze bushing, those have better wear properties. Remove your primary shaft and measure it. Get a bushing with that ID, and a drill bit for that OD. Extra long drill bit. you'll need to get clever to jig up your base plate to keep the drill bit going in straight.
Chill the bushing and press it in without bending the base plate. Red loctite too.
The jigging is why it's expensive. Chances are good you'll mess up your baseplate if you don't get it 100% straight.

Good luck!

PS - are you sure you even need this? does it wiggle, and leak air there?