Ok, lets get back to this one. I ended up not using the right angle attachment, I did find it but it was dope, just wouldn't work right and it kept swiveling around. Just a real big PITA. So then I got my old trusty Craftsman 3/8" old drill out, had it since like '86 or so. It would fit between the joists and had enough torque to go through that old wood. I drilled 3/4" holes in every joist I needed, about 12 (first round of holes) I used a combination of a stubby spade bit and a stubby auger bit (kind of lame).
I had to drill 1 1/2" holes in 2 joists that made up the cold air return to run the conduit through. Drilling the 1 1/2" holes was another story. The first one went pretty good, just used the 1 1 /2" spade, it took a while but got it done. The 2nd one was a bear, the angle I was at was bad, drill was heavy, everything was just awkward. It took me a entire week to get one hole drilled. All of the holes were overhead but this one was just horrid. I used a spade bit, a smaller forstner bit and a 1 1/2" hole saw.
The reason those holes are 1 1/2" is because I had to seal up the holes; I used a piece of 1" schd 40 pvc to put through the 1 1/2" hole and a 6" tail piece on each side to seal the hole. I'll go out later to the cold garage and get the caulk to make sure it has a real good seal.
Here's pics of the cold air return w/the PVC run through it. The 1st pic is the pvc and tailpipe outside of the air return. The next 2 are what it looked like once I ran it through and glued it up. No caulk yet. Also, the reason it is back in like a hole is because my kitchen cantilevers out over the house foundation like 2 ft. When I get this electrical done next is time to start on drilling holes for the new pex install; that will be up through the joists just above where the galvanized plumbing is now about 6" out from where the electrical is run.
It is an older Bosch.
