I don't know any specifics regarding the drive system on the 10ee, but its my understanding the variable drive system is full of obsolete parts, vacuum tubes, mystery components, etc. all of which are either now unobtainable or outrageously expensive.
That Bradford looks pretty nice!!
I have to reply to this,
The Monarch 10EE is an enigma to most, there are several different drives and, good to superb support for most. Tubes and old switch gear are available as well as modern replacements at reasonable prices. The only issue is, you have to be willing to do the work/trouble shoot yourself.
From rewinding motor/generators to installing new off the shelf solid state DC drives and, repowering with an AC motor and inverter. There are solutions to nearly any issues with a 10EE drive. More and more DC drives are being repaired or updated instead of replacing the motor, a DC machine tool motor has many advantages. AC drives and motors are getting better but, the DC motors Monarch used are really top notch, with power and torque ranges AC drives can't match. Monarch uses a much larger AC motor in machines the sell today.
I am not singling out John, just using his comments as a common chant about the mysterious vacuum tube lathes. The tubes by the way can last 40 plus years in daily use. Yes there was a time period when the old fixers retired/died off and, new blood figured out the mysteries of Monarch, today there are many who learned that it ain't rocket science to keep one running.
Steve