You probably have 3-"Hot" legs , 1 neutral, and 1 ground in your garage. The lathe probably just has 3- hot legs and a ground. You can pull you electrical panel off of both to see how they're hooked up internally and use your tester to determine the rest.my new lathe have 3 phase 4-pin and i have 5-pin red 3 phase in my garage
i have already spoken whit an electican, but i dont learn anything if i pay him to do the job.