What sort of machining equipment would you suggest for a guy that wants to dabble in 80% lowers and threading?
Barrel threading? Because if so, you're really looking at two separate machines. I've never seen a combination mill/drill/lathe machine that would be capable of barrel threading.
For 80% lowers and other light machine work, you really can't beat the little Seig X2 and it's variants sold by Harbor Freight, little machine shop and Grizzly. They're pretty capable little machines if you take the time to set them up right and dial them in. I still have mine, use it frequently for drilling and other secondary operations. I have a tilt/swivel vise on it, so if I need to make a compound angle cut that doesn't have to be super precise, it's a lot quicker than fixturing in my big mill. I actually used it to drill the firing pin holes in my O/U pistol with their wonky angles on two axis. This is mine, sporting DROs and a modification to Z axis for more travel:
Mills are also fantastic for internal threading. I power tap a lot with spiral flue taps, especially through holes, but even if you're not comfortable doing that, you use the quill with a tap guide centered over the hole, and you will have perfectly true threads every time.
For barrel threading, however, if you're wanting to turn out precision work, there's no better way than single point cutting. But that takes a fairly substantial lathe, and some experience. I wish I could tell you there's a good alternative, but if you're threading for suppressors, it needs to be pretty dang straight. I actually do not have single point threading capability on my lathe, but can make custom die guides and wrenches to perfectly fit a bore or major diameter, and I use a chuck on the carriage to apply perfectly even pressure to the die. Now, mind you, this is after I've indicated both ends of the barrel with a spider and 4 jaw chuck, then turned it true.
This is a custom die wrench I made for threading 1/2-28.
The die is a very tight fit (tap it in), and is perfectly centered to the guiding bore:
And I can turn out some pretty nice threads with it
But it's still a lot of careful work to get them true to the bore.
In summary, the mini mills are cheap enough, small enough, and handy enough to easily justify purchasing them. Vertical mills are the most flexible machine tool, and you'll find yourself using it for all kinds of things you did the hard way before. But unless you plan to thread
a lot of barrels, you'd be better off paying to have it done. Even a used lathe you found on the cheap probably wouldn't amortize it's cost threading your personal barrels until you did well North of 20.