Four options for an unwilling builder

[Maurizio]

Bah-humbug.
I'm sure everyone has their own greatest pleasures, and for me it is using tools to make concepts, rather than making tools (CNC).

As such, I was hoping for some advice on the following four options for my given use.

My use(mm):
A 400X 300Y 100Z working lengths (plus a bit extra Z clearance)
Hardwood or Aluminium
Precision - +/-0.003 seems to be the goal for journal bearings for making bicycle brakes. I suspect there is quite a bit of leeway here, and tool wear will be important. (Calculated using an ISO online calculator for hole tolerances) - as my important tolerances will be holes, it might be possible to circumnavigate machine precision milling in favour of precision drilling.
Resolution - Using a 0.2 end mill to do small carvings on a 17x17 square (keyboard caps)
Repeatability - I would like to do some small production runs (if that evolved then there would be the self generated funds to invest in something truly industrious)
I have a max budget of £1600, plus a bit extra for end mills/making a table to mount it to.

Option 1. Buy it. Doesn't seem feasible, the budget machines represent poor value for money and poor accuracy and to cap it off are geared towards sheet goods.

Option 2. Buy it second hand. Solely dependant on a machine being available. Potential risks with wear.

Option 3. Convert a Mill (used or new) - very very tempting. As my work surface isn't very large this could work, the frame rigidity and slides are already taken care of. I'm a bit concerned about adding the appropriate steppers and balls crews in case clearance is a problem. Additionally I'm not wholly settled in my current place, so moving with this could be a nightmare.

Option 4. Build it sticking to a KISS mindset. I've drawn up plans and budgeted it - it works! However, a fair amount of work, with potentially variable outcomes. I would also have to settle on the 'best' compromise, which after 17 different machine plans so far might be tricky.

I'm posting this because I'm already a few hundred hours into option 4 and I can see it growing arms and legs before it's done. As using, rather than building, is my goal I wanted to check whether to nix it now, rather than down the line.

I would love to hear from anyone who has gone through a similar experience, has experience with the different machines, or insight into my (perhaps incompatible use goals).


Mille Grazie,

Maurizio!