I suspected as much from what he said. I wanted to re-enforce the idea that, when threading, the only reason for reversing the gear train was to cut left hand threads.
For someone new to cutting threads, it can be confusing when using an unconventional threading method. Threading from left to right, internal or external, inverted cutter, they are run all with the gear train in the forward direction ( the lead screw feeding the carriage inward for normal spindle rotation) for right hand threads.
I added a tumbler to my G0602. For lathes that don't have the reversing tumbler, a workaround for cutting left hand threads is adding an idler gear to the gear train when cutting a left hand thread. It's a less convenient way of accomplishing what the reversing tumbler does but easier to implement. There have been a few previous posts regarding adding an idler gear.
