Not sure if you are using a multi-tool turret, or a standard Aloris type toll holder system.
Either way, try using a cobalt tool the full length of the turned area, and plunge straight in until you reach the thread root.
The cobalt tool should have a nice chip breaker groove to curl up the chips.
The 16x60 lathe has more than enough power to accomplish a massive cut like this, so let the machine do ALL the work!
Do this to all then turn as normal!