6. You talk about turning SS or Titanium, making grooves, screw cutting, using indexable tools. To be honest, based on our experience with beginners, you will end up in a hole, be disappointed and loose interest if you go down this path, without any training, unless you have strong willpower to learn without pointing your figure at others when you make a mistake because of your lack of knowledge (sometimes such beginners raise 'the not fit for purpose' card with us). Majority of beginners will easily break indexable tips, without formal training, because of incorrect use of tips, feed rate and speed. Screw cutting is also something which needs to be learned if using a lathe tool, and a little easier if using a die in a die stock. If using a lathe tool, metric lathe for true metric threads, and imperial lathe for true imperial threads. There are lathes which can do both – using certain combinations of gears, but the key principal is as I have suggested.
7. After you have purchased a lathe, you will need some lathe tool bits, HSS or indexable, tailstock chuck and arbor, parting off tool and blade, your own bar stock to turn, some drill bits and off you go. There after, provided you haven't given up in the first three to six months, you will add to this other tools as you feel the need, probably a revolving centre, face plate with faceplate clamping set, and/or a four jaw independent and/or self centring chuck. Three to six months later, maybe a fixed/travel steady and/or a vertical milling attachment. If you are going to work with hard materials, you may/may not need/use a coolant/coolant system. You may also want taps/dies/die stocks, and the list goes on. So, within six months to a year after buying the lathe, you will have spent nearly as much on tooling as you spent on the lathe, depending on what you intend to do with it.
At the end of the day, please also remember, you get what you pay for. This is a hobby, and hobby prices are cheap, which in turn means that you may have to do some work yourself to any Chinese lathe you buy, to make it meet your specific end needs. In the old days, you had a machine tool fitter to come and make adjustments to a machine before it was commissioned. Such skills are still available to those willing to pay the price, which is outside the scope of a hobby user. Forums such as this and forums dedicated to specific machines are there to help. If you are expecting high quality brilliance at a hobby market price, this will not happen.
I am aware that there are people here who will disagree with me, but this is my point of view.
Finally, in my opinion, a lathe mill combination is a bad idea. Again, this is my opinion, and for this reason, we do not sell such combinations. However, if you have limited space, I suppose this is something you have to consider.
Ketan at ARC.