Feedback for my machine

Sorry for not being able to explain better. English is also not first language.

I am trying to design a small (650x600 mm footprint) desktop machine for milling aluminum. I think I want to closed loop. At least I do not want to design for it to add later if it can get better with closed loop without breaking the bank totally (since it is a hobby). Will be using Aliexpress/Stepper online stuff since otherwise one ball screw can cost $600.

Having hard time to choose what to use. I have read the posts on linear scales and see that people have tried different things. Wondering what the community has as input for choosing one of the below.

1.     Open loop stepper and driver. Cheapest but lacks feedback. This will maybe be as good as point 2 if we know that motor does not skip steps?

2.     Closed loop stepper driver system. This will give me information on where the motor is. Maybe no gain if we know that system in point 1 does not skip steps.

3.     Open loop stepper and driver and linear scales. Same “cheap” stepper and drivers (as in point 1) and add linear scales for feedback. Gives information where the table is instead of the motor, thus a little more accurate than point 2.

4.     Closed loop steppers (or steppers from point 1 with rotary encoder) and “normal” drivers. Steppers send feedback to LinuxCNC (through Mesa) and not the driver. Basically, the same as point 3 but measure where motor is instead of the table. Easier to mount than point 3 but “less” accuracy. Cheaper than point 2.

5.     Closed loop stepper driver system with linear scales. This will be most expensive. Is there a advantage of two feedback systems? Will one be used between motor and driver and then the linear scales will go to LinuxCNC (through Mesa) and make adjustments.

1 is of course the cheapest. But 4 seems cost effective and easier to mount rotary encoders instead of linear scales. Next step in cost would be to go for 3, little more money but harder to mount.

Normally i would ask how much you want to plop into this, but if using ballscrews at 20mm or over i would spring for some proper servo stuff, be it from Leadshine, Delta or preferably Sanyo or Yaskawa.
People cut aluminium with wooden CNC's so ....
On the same boat as i need something similar and i do have a lot of weird stuff around the shop, but thinking of doing two of them, i just have one problem, no place to get the screws cut and turned properly.

Many screw suppliers will custom cut/grind your screw ends to your specifications for a small up charge. (Often more than well worth the cost.)

Yes they do, last time i asked several years back they wanted 380 Euro for machining only 3 of them, not to much when you consider the price of the screws.
The issue is i have 2 of 2505 at 2.4 meter length and a 60cm 2505 that are not machined, so cutting them i can do, turning them on a lathe i can also do but it will not be usable as the lathe has 0.2mm off-center, the best i can do is have a friend turn them at 0.1mm, but still not good.
Goes to show that saving a bit here costs a lot later ....

Last time I did that, it was 40 for the screw and 100 for the machining. Per end.

You could think about driving the ball screw nut instead of the ball screw, then the quality of the machining doesn't really matter.