It be helpful if you could post the serial number plate. Monarch made a lot of special "One-offs" of their standard lathes and sometimes you can pick that up in the serial number plate.
As far as I can remember threading was standard feature on 1000EE-Series 71 as it was to be a larger toolroom lathe.
John
+1 What with ""build to FIRM ORDER" and extensive options, Monarchs were mostly "one-offs" in one way, another.. or several.
Best of all, if you have not already, phone or email Terri at Monarch and order the factory manual / build-package sort-of "reconstructed" from her extensive by-SN# as-built files.
"Time has passed".
LOTS of time.
MANY Monarchs have had field modifications done to them either by prior owners and local staff, or even by DoD "Depot level" contractors.
What you have NOW is.. whatever it IS!
Not necessarily the same as when it left Sidney, electricals and final-drive motor especially.
In an unrelated thread, it has been ascertained that Sabina routinely had 230 VDC 10EE motors rewound to 440 or 500 Volts DC, for example.
"Nominally", that
can roughly DOUBLE the available peak HP in the same casing/frame.
One more mystery now less mysterious as to how Sabina configured for top performance whilst some
other of the many DC Drive conversions were smooth-enough, but
de-facto DOWNGRADES as to (reserve) power to the spindle and work.
Mostly, it came down to what any given purchaser NEEDED the most.
2CW