Yes, I did figure something out. The 1/4' drive that comes in the holes saw kits wasn't going to be rigid enough for this application. I also wanted something that would handle the pounding and vibrations an interrupted cut would produce.
The standard arbors I had found only had a jam nut, nothing to stop the hole saw from spinning if it got stuck or wedged while in the cut. There is a lot of surface area on this one. Looks like I'll need to make my own.
I found a chunk of round stock and got to work on the lathe. Then into the mill. Just enough room on the side of the frame setup to widdle this out.
It have 2 dowel pins that keep the hole saw from spinning and a small set screw give me a low profile inside. This would give me the longest depth of cut before the inside of the saw crashed into anything on it's way down.
1" shank to fit in my BT40 tool holder.
And now I have a rigid tool that's ready for some work.
On the left is the wimpy setup that's used in a Hand drill.
On the right is the new "Uber" Cutter.
This is a large Hole Saw.