How good is a sub ?100 3d printer ?

[curious aardvark]

good idea. I reckon if I move it up and measure the distance between the rods and the bottom of the top frame, that should help. Obviously you need to level the bed after.
In fact I'll do that now :-)

Well it was way off. But pretty sure that won't make any difference.

When you move the y-gantry up and down, the whole extruder mechanism visibly rocks back and forth.
I'll see if I can video it.

It's not related to how level the gantry is.
And the screws don't wobble any more. Could it be some sort of misalignment between the smooth guide rods and the screws ?