I bought a Huanwang vfd from eBay around 3 years ago for my lathe - no problems at all. I also had a motor which needed the star point digging out - not difficult at all despite never having done such a thing before. Since then I’ve bought another couple of vfd’s on eBay secondhand for not much money, to run a shaper and a mill. The vfd rating doesn’t have to match your motor btw, it can be higher eg a 3hp rated vfd will happily run a 3/4hp motor.
A cheap alternative to a vfd for a small 3 phase motor is to simulate a third phase by wiring in a capacitor - called a Steinmetz connection. You have to experiment with the capacitor value - somewhere between 10 and 60 uF - and check the voltages across each of the three ‘phases’ to try and balance them out as far as possible. There are a few videos on this by Andy Reynolds on YouTube. I’ve done it for the motor on my little Chinese hacksaw and not had any problems, but I’m not sure I’d want to do it on a lathe or mill which could run for long periods. My 750w motor needed a 30uF start/run capacitor rated at 450v bought from an eBay supplier. I think John Doubleboost has also done this for a pillar drill, and put out a video about two years ago.
