While I've been waiting on the boring bar... laid hands on some second hand drills. Flea market junk, all bunged up cutting edges. My HS machine shop teacher would be proud. I sharpened them, using my drill gauge to get the angle correct which they weren't. I center drilled all the way to 3/4"... very neat & slick. I just have a little more to go.
I borrowed a boring bar with carbide... it's round with a flat top & bottom. Freakin thing will almost go in my quick change holder... takes 1/2" cutters. I got permission to grind a bit on the top of the cutter (since it indexes off the bottom.) So I take off a few thousandths & I coax it into the quick change tool holder... It's too low, won't go into the piece.
My 1930's SouthBend is old school... the tooling today is built to different systems it would seem. I'm digging in my drawers for the old tool post adaptor but am afraid it's still not going to work...
I thought about a spacer under my quick change tool holder. I can't take this piece out of my chuck without losing my center accuracy... so making a spacer isn't going to happen. I have maybe 3/8" threads on the center bolt through the tool holder.
I can't grind more on this borrowed tool. The carbide doesn't stick out very far & still might hit the work under the cutter. I guess I need to pull the boring bar & test for clearance before I go too far with fixes.