Just how much ofa 3d printer can you actually print ?

Been thinking about this - and one reason i designed the aluminium extrusion profiles.

So the things you absolutely cannot make on an fdm machine:
electronics - motherboard, screen, sensors.
hotend
printbed
nuts and bolt - well bolts anyway, you can make effective nuts quite easily or simply screw the bolts directly into the right size holes so that they self tap.

So the things you absolutely can print:
wheels with bearings
belts (been making my own belts and cogs for use in rotary axis in my k40)
frame components
standard profile extrusion
extruder
gears

If you were to go with an unheated print bed - then you could make one out of plywood and a buildtak sticker, not actually printed but still homemade :-)

so as a minimal list of things you'd need to buy to make a basic i3.
stepper motors
motherboard
screen
bolts
hotend
end stops and thermistor
z screws

Unless I've missed something that's it.
If you wanted to make a small delta then you'd also need to buy rods - although tent pegs and some printed endcaps using metal washers - would probably suffice.
Also with a delta you don't need any z-screws. so assuming you can get some thin, straight metal rods (poundland bbq skewers come to mind) you can print everything involved in movement quite easily.

The thing is I've got 4 small stepper motors and all the other bits and pieces in my workshop.
So I'm thinking if i were to make a small fdm printer, just how much can I actually make from scratch ?

I also have a k40 and some shets of 3&4mm acrylic - but I'd rather print everything if I can.

I don't like the central y rail only i3's - but there's nothing there you can't print from the wheels to the extrusion.
And if it's only a 150mm print volume - I see no reason you can't make the entire thing.
But you wold need the z screws.

So all in all I think a small delta is the machine that can be made from the most printed parts.

Anyone done anything similiar ?