z axis get stuck

[trencapins]

The left Z smooth rod can't be put in it's hole. If I do so, the Z threated rod simply can't move.
If I leave the Z rod outside it's hole --> I have a terrible z wobbling.
I have reviewed the assembly twice and parts are mounted correctly.

[waldamore]

i also had to drill the hole a little to fit in the screwed rods.
later i printed this and i'm very happy now: http://www.thingiverse.com/thing:1920478

no more z-wobble, no more loud noises