i was able to solve the problem,
i simply took a 8mm drill and drilled all the holes a bit wider.. now the pipes fit BUT i hit the next problem:
one of the vertical pipes, grinds on one of the bearings of the horizontal axe, meaning it blocks smooth movement.
the bearing of this part is not in the middle, i cannot twist the part, because its one of the two parts which are screwed together in the middle of the Z axis...
i tried to drill the hole to an elypse but this did not help, the bearing needs to be like 1mm more away fron the Z axis pipes.
this problem does only hit ONE of the Z axis pipes, the other one is fine... ??
the bearing scratches the Z axis pipe, it cannot move, because the bearing reaches this pipe, which is not intended.
i think it its because the black parts are not broad enough... if they would keep 1mm more distance between the orange parts, the problem would not exist. i think this canno be solved by drilling, the part needs a scale, redesign or some kind of spacer is needed.
it also would be fixed, if the printing high of the orange parts would be at least 1mm taller, so they would have a bigger distance at their bearing in relation to the Z axis, there is no reason let it be so close the Z axis pipes.
maybe my printer pressed the first few layers of the part to much down on the bed, so the high of this part was changed in the negative -> leading to this problem.
i think i print it again on my second printer the check.
here are pics:https://goo.gl/photos/cJRLSvYbkMVnewen7
you can see the left/inner bearing from the X/Y axis... this one scratches on the Z axis pipe.
edit: the problem now is on both Z axis pipes... i forgot to tight the screws... the Z axis pipes are blocked be the bearings of the X/Y axis, the bearings reach to far in the direction of the Z axis pipes, so they scratch them hard enough to block movement.
solution: the distance between the orange parts on my pics, needs to be greater... there is no need to be so close together.
pls, make them just 2 mm higher or do this with the black parts, they are the spacing between the orange parts.
edit2: i added washers between the black parts and the orange one, just to show you what i mean... this fixes the problem because it adds clearance to the bearings from the X/Y axis... but is not a good solution, kills the rigidity of the Z axis