z-axis coupler and threaded rod

[ash2k14]

Hi, I ran into problem although I alternatively solved them. My printer is running fine but the z-axis threaded rod were bent from the start causing my extruder to wobble back and forth. Not to mention that the coupler also didn't fit the threaded rod supplied.

Threaded rod measured at around 7.7mm while coupler hole measured at 8mm, there is no way of fixing the threaded rod into the coupler. Although I printed a printable coupler to make the z threaded rod spinning with the motor, but this is not appropriate to supply an inadequate and such a lack of quality control to consumers

[zhangxueyou]

There are 2 screws for firming the threaded rod to coupling.

[ash2k14]

it is useless, even tightening it also the threaded rod are loose inside and can be slid out. Furthermore the threaded rod were bent as well

[zhangxueyou]

Maybe it was bent during transport. You should tell the customer service.
But I still can't imagine how the rod can not fit the coupling.

[ash2k14]

Like I said, the threaded rod were measured at 7.7mm diameter while the coupler slot is 7.9-8.0mm diameter. Even tightening the bolt never gripped the threaded rod. I will post a picture tomorrow about the measurement differences of the threaded rod and the coupler slot

[ash2k14]

I am sure you are not assured when I started this thread, here is the picture of the measurement as promised.

NOTE that the coupler has been tightened when measuring it


[Imgur](http://i.imgur.com/Y9JMDrK.jpg)

[zhangxueyou]

My rod diameter is about 7.8mm, and coupling is 8 mm. They fit each other if I tighten the screws.
There are 4 screws in coupling, 2 for narrow the hole, the central 2 for tighen rod and motor shaft. The srew should face to the level side of shaft.

[ash2k14]

My coupler only got 2 screws there are no small screw hole for grub screw to lock the threaded rod nor the motor shaft on the coupler. Picture attached below for proof that no grub screw holes

[zhangxueyou]

Look, there are still 2 screws in coupling:

coupling.png (249.47 KiB) Viewed 17240 times

[ash2k14]

Look, there are still 2 screws in coupling:

coupling.png

Here is the thing that i rotate to let you see if there is any extra 2 screws to clamp down the rods or not