Hello, i have bought this printer a while back but after many time spent calibrating and what not, i still can’t get a decent print, i am despaired, please, if there is anyone out there that knows what i need to do based on the following pics, let me know, any information you’re willing to give is crucial 
As you can see, there is an ENORMOUS Z wobble and the corners are FAR from square.
Thank you very much in advance
You need to make modification like :
and if you want a very good quality, you can change the normal threaded shaft by a trapezoidal spindle like TR10x2.
There is already a lot post about these modifications
Hello, thank you for the reply, i have got a flexible coupler for the motor, the only thing i don’t have is the Z motor bracket, but how can the bracket improve anything, my prints are reaaally bad as you can see 
Hello tigox,
Mount your flex coupler, print the new Z motor mount, it will be wobbly, but still better than the original. Then mount your motor on your new Z motor mount, and print the same mount, it should be a lot better quality by now. I had the same problem, this helped me alot. Also, upgrade your spindels to trapezoidial in future if possible.
Hope this helps
i’m sorry, but what is the spindle?
oh, i see, thank you very much for your opinions, unfortunately i do not have the money to replace the whole spindle assemble and also re-do the code to embrace the new spindle
Hi tigox,
where (approx.) are you located?
Cheers,
kuraasu
I am so sorry for the long time to reply, but i have been working and studying, thus i lost track of the post; i live in Portugal my friend 
Also, i saw a lot of posts on improving the z axis, is there anything i can do without having to print upgrades? because i would have to improve the z axis before a i the upgrades as i can’t print anything anymore…
This printer is a nightmare, the four corners of the print always lift and the vertical surfaces are like the Atlantic ocean…
Hi tigox,
I’ve experienced similar problem after installing new flexible coupler, hobbed bold and re-calibration of steps per millimeter of the extruder motor. Coupler and hobbed bolt worked well until I made calibration - more (yet, correct) amount of extruded plastic revealed that I have serious Z wobbling. It seems that the reason for this effect is Z-step skipping which occurs due to larger friction between Z linear bearings and rods when Z-carriage starts to wobble forced by the the spindle.
What helped me to resolve the problem:
Now the wobbling is gone! Hope it will help You.
Thank you for the suggestions :D, i will try them, but what do you mean by removing the top bearing and clamp? what would i hold the spindle with?
Actually, the top end of the spindle doesn’t need to be secured - this will only make the construction less rigid. I’ve found this solution here: https://www.evernote.com/shard/s211/sh/701c36c4-ddd5-4669-a482-953d8924c71d/1ef992988295487c98c268dcdd2d687e
Hum, i have indeed seen this post, but also got me thinking if the Z axis won’t become unstable especially at the vertical extremities?
I don’t think that will be a problem since Z axis is indirectly coupled to the frame by linear bearings and guide rods…
I have made s sketch to illustrate the idea of modification:
here the blue dots denote the points of secure mounting of spindle. The green dot is the point of “weak” connection of the axis to the frame through the Z-carriage. So, in the three point assembly, the wobbling axis will cause the Z-carrige to wobble and make exess tension on linear bearings, increase friction and finally lead to missing Z-steps. In the two point assembly the axis wobbling will occur between motor and Z-carriage, and at the upper end or the rod, but the Z-carrige will be held in place by bearings/rod and move more freely, I think.
I don’t think that will be a problem since Z axis is indirectly coupled to the frame by linear bearings and guide rods…
I have made s sketch to illustrate the idea of modification:
here the blue dots denote the points of secure mounting of spindle. The green dot is the point of “weak” connection of the axis to the frame through the Z-carriage. So, in the three point assembly, the wobbling axis will cause the Z-carrige to wobble and make exess tension on linear bearings, increase friction and finally lead to missing Z-steps. In the two point assembly the axis wobbling will occur between motor and Z-carriage, and at the upper end or the rod, but the Z-carrige will be held in place by bearings/rod and move more freely, I think.[/quote]
Hum, interesting, i will try it out when i have the time 
Another suggestion is to print something like this:
thingiverse.com/thing:263650
thingiverse.com/thing:161957
This will decrease the z-wobble. Because if you just hang it around the original one it will get so much tension that it can move the whole Z-beam up and down as it demands filament.
Hello,
I had the wobbly z shaft as well, but not as bad as to give bad results.
I found the problem to be that the Z-axis stepper motor was taking the strain when lifting, instead of the top bearing.
Using the original parts, I loosened the Z-axis connector grub screw, and also the top bearing mount screw, and raised the top bearing mount a few mm’s to take the strain off of the motor, and retightened all screws.
This took the strain off the motor, and stopped the wobble.
Hello,
looking again at your sample pics, it looks more like X - Y axis problem. Are your belts correctly tensioned, and not too loose?
that is Z backlash and Z rod not straight. you can fix it by printing something like this: http://www.thingiverse.com/thing:304424
