you can do a ton on a small lathe, even if it doesn't have threading box. Lathe threading is really annoying and you probably wont ever need to do it more than a few times in a decade lol i really only use the box for knurling which is fun.
things to consider: HP, pass through bore, swing size.
my older lathe was a 1.5hp 3ph on a static converter so basically 1hp on single phase 220. it was pretty decent but could have used more power
small lathes you will never find something that has a 3" pass through, 1.5" if you lucky (drive shaft work). a good steady rest and live centers will get you far though if the bed is large enough.
my new lathe is 3hp on a rotary converter and loves it.
i wanted a big enough swing to do rotors or axle C's.
a shitty random old lathe can be made pretty decent with some good tooling / holder upgrades. most you will find they just haven't been lubed, maintained, adjusted and just need some playing around with to tighten up. its not like we are doing aerospace work here.
buy the biggest one you can fit! store shit on half the bed normally but have machine if you need it lol
