Overarm adapter - 2.375" to 3.5" - trepanning?

Thanks for the input everyone. I have my answer, I guess I'm going to spend some time drilling and boring.

To answer the questions about what I didn't include before: the chunk of material I have is steel, I believe, I think probably part of the overarm from whichever horizontal mill this M head was attached to at some point in the past. My lathe is a WM210 lathe (9"x30"), and I don't currently have any drills larger than 3/4", even if my lathe could power a 2+" bit. I'll see what I can come up with, obviously I don't want to spend hours running boring passes if I can just drill it instead.
 
I don't imagine that a 9" lathe has the power to use a 2" drill in steel.
If boring you must, until the finish passes, use a shorter (more stiff) bar from both ends to maximize each depth of cut and feed rate. It will be faster than using a 5"+ long bar all the way through for each cut.
 
That's going to be a tough job on an import 9x30. Doable but tough. Trepanning deeper than 3/4" or so can be challenging without the right insert tools (and lathe). A holesaw from both ends might work if you have a fairly beefy drill press (do it on your horizontal?), though it'll be slow going and tedious. Drilling and boring from both ends will definitely work, it'll just take a long time. Use the biggest boring bar you have that will fit in the hole that you drill. Do a final pass (or two) from one end - it'll be worth looking at your scrap pile and seeing if you have a 2" bar of some sort that you can stick a bit of HSS in one end and bolt to your carriage.

I drilled a piece of 3" stainless out to make a mortar (of a mortar and pestle) on my Atlas 618. Definitely a labour of love and it took me HOURS, but I did it :)
 
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