Well, when all else fails read the manual. At the end of the grounding instructions it says that neither of the two 1642 lathes (i.e. 115 v nor 230 v) can be run on a GFCI circuit. I was starting to think it was just the 115 version and I was kind of regretting that decision. Okay then, we'll see if my electrician will swap out one of my outlets or if I have to go rogue.
Thanks for the pic! I was actually planning to make the inside legs at 90deg like this to help with the "knee knocker" issue but hadn't considered putting shelves on them. It removes from the traditionalness of it being able to break down into the smallest possible parts but I really like this. I'm at least 6 weeks from starting so I'm sure things will change a dozen times before then.
I decided to try starting the lathe at a set speed, I.e. not ramping it up from zero. It tripped the gf outlet immediately. So it is the motor which converts one phase to three phase that is the problem, not changing the speed. googling found a bunch of other people with this problem. A call to Jet might be in order, probably best done by my electrician who can understand the answer.