sizing servos for a cnc lathe

I'm a bit late to the party, but have you considered using Parker's motion sizing software to select a motor size? I used it to select motors for a CNC lathe conversion, and found it to be quite good.

Parker Motion Sizer, Rev 3.22 may be downloaded from the Parker site at www.parkermotion.com/scripts/support_downloads.asp#SIZINGCD

I wound up calling Glentek and getting drives from them for the machine. Wound up with smb 7275 drives, 10hp brushed servo motor on each axis. Also wound up with a Siemens simoreg DC master 60hp spindle drive.