"My Google" found this, world of knowledge in there, it all works as claimed, no guess work.
https://www.mitsubishicarbide.com/mmus/catalog/pdf/b/b095a.pdf
I also noticed that some suggested doing the job on VMC, using end mills to prep pilot hole, reaming .... etc.
Now the reason why this is lathe work and there can be no argument against it.
Spinning drill can drill a hole at any location on work piece, strait or at the angle relative to other features on work piece.
It means that round work piece clamped in a wise or indexing head would have to be perfectly lined up with spindle to produce hole concentric to OD of the work piece, this concept is equal to pissing into the wind, with equal result.
You want to spin the work piece instead of spinning the drill and here is why.
Toll such as drill, having angle on each of two flutes will be forced into center of spinning work piece because each flute deflection results in canceling of the other, therefore staying on center of spinning work piece.
Simply put, this results in hole being concentric to OD throughout the cut.
You want drill to be on center line so that as it gets deep into the hole, it doesn't rub with back end.
Long carbide drill will tolerate some bending if it's not 100% on center, but you want it as perfectly centered as possible so that cutting tip is not fighting to stay on center of spinning work piece which, as noted above, will force drill to center of work piece even if it is off center.
For sake of argument, consider this, if you hand grind a drill and one flute edge is slightly longer then the other but having same angle, meaning that drill point is not on center of drill, tip of drill will still be forced into the center of work piece providing drill is long enough to bend and confirm.
The resulting hole will still be concentric to OD but it will be oversize due to the fact that location of center point is shifted and longer flute acts as a boring tool while short flute edge cuts smaller diameter then it would when tho flutes are same length.
In days of conventional, cam driven, screw machines such as Acme Gridley, I could hand grind hand full of drills daily and rarely have one cut oversize. Back then drilling 1.5" deep hole required 2 or 3 drills depending on cam installed and each drill had to cut same size to not show steps or spiral marks.
Now days, I can only come close, lost the touch after so many years of not doing it.
My first encounter with super alloys and drilling deep holes has been result of other experts trying everything else first, the hard way then submitting to last result, which is "right tool for the job", concept that saves time, money, ensures success and breaks egos of leads and managers, I got the job done, got the credit, got the raise and ............. made no friends along the way, idiots hated my guts and got me fired from jobs in few cases.
In any case, I hope some useful information was offered here, I hate to see people do stupid things and suffer as a result of self inflicted wound.