You have a couple options. All of them start with running enough single phase 220VAC to run these machines. A Bridgeport is usually 2-4 HP and normally needs a dedicated 15-20 amp feed to cover startup. Plus whatever else you might have running. Plus cool new tools you'll decide you need.
240VAC 50 Amps is kinda the min for a machine shop.
Then you can do a couple things.
1. You can put a single phase motor on the machine. Depending on motor size, casing, and your cragslist skilz this is sometimes the cheapest solution. Also depends on how the existing motor is. If it's already kinda worn out, then sometimes it makes sense to swap for s single phase. I helped a buddy do this on a Monarch Lathe last year.
2. You can run a VFD. You would need one per machine usually. (You
could get one big honking one and wire several machines, but it's not ideal). THis is nice because it adds variable speeds to a machine that probably only has step pulleys. Nice feature. Something like so:
Cheap Chinese VFDBe aware that the chinese VFD's are overrated, so buy about 150% of the size you think you'll need for the machine.
3. You can get (or build) a rotary Phase converter use it to feed 3 phase to all your machines.
Video on phase converter I know a guy that has a
huge one of these in the cieling of his garage and feeds a Haas CNC, as well as two lathes and a Bridgeport. You will need a big honking motor though.
4. If you think you might be getting into using a bunch of three phase, you can have the electrical company just bring three phase to your shop. My boss did this in his garage, and it wasn't free, but it was under a grand, and he has all the power he needs. I am jealous.
Try and plan for the future, though. There is nothing worse then getting something all set up, and finding a deal on a new machine that necessitates rebuilding your infrastructure. FWIW, VFD's are the cheap and easy route, but you will lose some amperage through them.
