Easy, Z axe wobbles.
Put the bed halfway.
Unscrew the 2 screws on top of the z-carriage, holding the plate, on top of the hidden brass nut.
The let the z motor turn, and check 2 things,
Does the axe wobbles? Then unscrew the bottom metal connector from the motor to the screw, and put it together again, in such a way it does not wobbble anymore. You have to tighten the 4 inbus screws very evenly, and not to tight. It is not easy, but can be done.
Then you have to check, that the top of the z screw is perfectly aligned with the hole in the top side of the chassis, i had to put some spacers between the motor support at the bottom, to get this done.
After that, you have to align the 2 axes, begin with the left one. Unscrew the 4 screws at the top of the 2 rods.
You pull the carriage up, and check if the brass nut passes perfectly in the carriage, without changing the position of the z screw. Then fix the left rod.
Check again if the z screw goes in and out the carriage without pushing the z screw away.
Then you have to align the right rod in the same way.
Once this is done, reatache the plate which holds the brass z nut in the carriage, and you are good to go!.
And be surprised of what the DV can do for you;-)
Thats sounds like a perfect solution. I was just looking at a tall model I printed and noticed that the lines are not visible near the top. So that would make perfect sense that the bottom of the rod is not quite center.
I didn't know about the adjustments on the bottom of the rod and just assumed that it was push fit into the metal collar.
Hopefully this will get my prints on par with my RepRap.
Thanks for the help, very much appreciated.
That sounds like a good plan. I too just spent the last hour fiddling with my coupler just as Rudy described. I could not make any improvement to the misalignment. Right now I am trying out printing a couple of different shaft coupler designs I found on Thingiverse. If one of them works, I'll let you know. Can you show a picture of your tubing type coupler?
Thanks so much for sharing your experiences! This gives me hope that I'll get mine tuned up perfectly with a few more modifications!
I think the best bet to reduce z wobble would be to upgrade the bushings supporting the bed. I see a lot of people try and secure the lead screw but I don't believe this has a significant effect. The 8mm metal shafts next to the lead screw are the ones supporting the bed. If there is any spacing in the bronze bushings it could cause wobble & the bushing would need to be secured into place without any wobble.