<p>So after reading the instructions more carefully, ANET do cover this in their operating instructions under <strong>troubleshooting</strong>. On closer inspection, I realised that the brass nut following the right hand thread seemed to be out of alignment with the stepper at the bottom. Fiddling with the flexible coupling helped a bit, but what I needed to do was place the assembly at the tight point, slacken the 3 bolts marked <code>SHCS</code> in the diagram, then tighten them again. I was expecting I might need to open out the holes, or re-make the white (factory printed) part, but this wasn't necessary.</p>

<p><a href="https://i.sstatic.net/5k8Wh.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/5k8Wh.png" alt="From ANET manual"></a></p>

CC BY-SA 4.0
2019-01-20T12:50:56.333Z
Found it in the A8 Operation instruction-1.1.pdf file provided on the SD card, page 66
Cactusbone
CC BY-SA 3.0
2016-11-21T11:42:55.380Z
ha! so there is caret nut :) it's good to hear you've solved it (btw: my suspicion about 1. assembling according to instruction was priviledged) ;) and 2. that there is a problem was priviledged too)
darth pixel
CC BY-SA 3.0
2016-11-21T12:53:28.793Z
I don't think `caret nut` is a real word. It is probably a mistranslation.
Tom van der Zanden
CC BY-SA 3.0
2016-11-21T16:57:35.007Z
@darthpixel - I would wager that `caret` actually means `carriage`, as in _the x-axis carriage_. Mostly because of the phrase in Tom's answer, _which can eventually hang caret_, which probably should be _which can eventually hang [the x-axis] carriage_
Greenonline
CC BY-SA 3.0
2017-04-04T21:38:45.710Z
where did you find this under troubleshooting, I think Im having the same issue. Can't find what you are refereing to.
user6668
CC BY-SA 3.0
2016-11-21T11:13:53.917Z
2016-11-21T15:44:53.670Z
2016-11-21T15:44:53.670Z
Sean Houlihane
<p>I assume you did everything according to the instructions but here is a checklist of what could be possibly wrong:</p>

<ol>
<li>Friction - check if you can rotate/move parts without lot of resistance</li>
<li>Screws - check if screws on couplings are tight and they don't slide over a shaft or thread</li>
<li>Stepsticks - check if they are cooled properly and similar (as there are two of them)</li>
<li>Carriage nuts on threads - check if they do not slide out of their nests while [the x-axis] carriage goes up</li>
<li>Filament - check if filament unrolls without resistance which can eventually cause [the x-axis] carriage to hang.</li>
</ol>

<p>IMO #2 and #3 are the most possible cause</p>

<p><a href="https://i.sstatic.net/4Hd33.png" rel="noreferrer"><img src="https://i.sstatic.net/4Hd33.png" alt="Diagram of issues 1, 2 and 5"></a></p>

CC BY-SA 3.0
2016-11-21T11:01:55.130Z
`caret nut` is a new term for me.
Sean Houlihane
CC BY-SA 3.0
2016-11-21T11:11:50.687Z
well - here is top left elem (prusa i2) where such nut sits http://3dprinter.my/cart/images/Reprap%20Prusa%20i2%20Printed%20Parts%20Black.jpg more or less the same is in prusa i3
darth pixel
CC BY-SA 3.0
2016-11-21T12:53:16.160Z
I don't think `caret nut` is a real word. It is probably a mistranslation.
Tom van der Zanden
CC BY-SA 3.0
2016-11-21T15:46:32.347Z
With (2), I had the spindle and the thread pressed tight together, the coupling was unable to bend...
Sean Houlihane
CC BY-SA 3.0
2016-11-21T16:58:33.677Z
@TomvanderZanden - I think `caret` should actually be `carriage`
Greenonline
CC BY-SA 3.0
2016-11-21T17:10:54.413Z
@SeanHoulihane the issue is to have screws properly screwed
darth pixel
CC BY-SA 3.0
2016-11-21T20:21:52.947Z
@darthpixel - Would you happen to have a source for the image and the checklist? Just to check the intended meaning of `caret`. I have downloaded the Anet [troubleshooting guide](http://www.anet3d.com/English/Technical_Support/Customer_Service/109.html) but it was not mentioned in that document.
Greenonline
CC BY-SA 3.0
2016-11-22T00:21:43.683Z
@greenonline checklist and image source, both come from my head :) let's forget this caret thing, I've just changed it in my ans
darth pixel
CC BY-SA 3.0
2016-11-21T10:58:58.947Z
2016-11-21T17:50:52.723Z
2016-11-21T17:50:52.723Z
darth pixel
<p>From <a href="http://3daddict.com/anet-3d-printer-common-mistakes-fix/" rel="nofollow noreferrer">http://3daddict.com/anet-3d-printer-common-mistakes-fix/</a></p>

<p>The motor shaft and the threading rod must have space between them in the flexible coupler.</p>

<p>That means unlocking the coupler from the motor shaft and moving it up a bit, in the end the threaded rod nearly touches the printer top hole instead of having like a 1cm gap.
This will allow the coupler to flex, and thus should handle small misalignments of the brass nut.</p>

<p>That's about point 2 of @darth-pixel answer, but before locking the screws, make sure to have empty space between rod and motor shaft</p>

CC BY-SA 4.0
2019-01-20T12:47:12.643Z
2019-01-20T12:47:12.643Z
Cactusbone
<p>I've actually solved this, but I think its still a useful question which I don't think is easy to answer with existing questions.</p>

<p>As soon as I'd built my ANET-A8 (Prusa i3 DIY kit), I found I was having problems with the extruder crashing into the bed. Although I thought I'd adjusted the bed leveling OK, the calibration seemed to keep getting messed up.</p>

<p>I tracked this down to two factors. First, I was winding the extruder head up some distance before loading the filament and starting a print. Second, at roughly half-way up the axis, the right-hand thread seemed to be getting stuck (more often when moving up than down).</p>

<p>What wasn't clear (and not mentioned in the building instructions) was what might cause this problem.</p>

CC BY-SA 3.0
2016-11-21T10:47:35.140Z
Is it correct to use the prusa tag for clones?
Sean Houlihane
CC BY-SA 3.0
2016-11-21T11:00:37.773Z
(thanx for creating it)
darth pixel
CC BY-SA 3.0
2016-11-21T12:54:18.340Z
@SeanHoulihane There's no such thing as a "clone". The Prusa design is open-source and in my opinion, "Prusa" refers to any number of designs.
Tom van der Zanden
CC BY-SA 3.0
2016-11-21T13:10:35.267Z
@TomvanderZanden Thanks for clarifying - I edited the tag :)
Sean Houlihane
CC BY-SA 3.0
2017-05-11T19:16:58.450Z
In many open source projects the name is trademark, while the designs are copyleft, the company still wants to maintain their brand (and reputation). However, I don't know Prusa's feelings on it.
HaMMeReD
<prusa-i3><z-axis>
Z-axis steppers and bed alignment problems
Sean Houlihane
# Z-axis steppers and bed alignment problems

(Asked by: username_0 on 2016-11-21)

I've actually solved this, but I think its still a useful question which I don't think is easy to answer with existing questions.

As soon as I'd built my ANET-A8 (Prusa i3 DIY kit), I found I was having problems with the extruder crashing into the bed. Although I thought I'd adjusted the bed leveling OK, the calibration seemed to keep getting messed up.

I tracked this down to two factors. First, I was winding the extruder head up some distance before loading the filament and starting a print. Second, at roughly half-way up the axis, the right-hand thread seemed to be getting stuck (more often when moving up than down).

What wasn't clear (and not mentioned in the building instructions) was what might cause this problem.

**Tags:** prusa-i3, z-axis

> **Comments:**
> **username_0**: Is it correct to use the prusa tag for clones?  
> **username_1**: (thanx for creating it)  
> **username_2**: @username_0 There's no such thing as a "clone". The Prusa design is open-source and in my opinion, "Prusa" refers to any number of designs.  
> **username_0**: @username_2 Thanks for clarifying - I edited the tag :)  
> **username_3**: In many open source projects the name is trademark, while the designs are copyleft, the company still wants to maintain their brand (and reputation). However, I don't know Prusa's feelings on it.  

---

## 3 answers

### Answer by username_0 on 2016-11-21. Score: 3 | Accepted answer

So after reading the instructions more carefully, ANET do cover this in their operating instructions under **troubleshooting**. On closer inspection, I realised that the brass nut following the right hand thread seemed to be out of alignment with the stepper at the bottom. Fiddling with the flexible coupling helped a bit, but what I needed to do was place the assembly at the tight point, slacken the 3 bolts marked `SHCS` in the diagram, then tighten them again. I was expecting I might need to open out the holes, or re-make the white (factory printed) part, but this wasn't necessary.

[![From ANET manual](https://i.sstatic.net/5k8Wh.png)](https://i.sstatic.net/5k8Wh.png)

> **Comments:**
> **username_1**: ha! so there is caret nut :) it's good to hear you've solved it (btw: my suspicion about 1. assembling according to instruction was priviledged) ;) and 2. that there is a problem was priviledged too)  
> **username_2**: I don't think `caret nut` is a real word. It is probably a mistranslation.  
> **username_5**: @username_1 - I would wager that `caret` actually means `carriage`, as in _the x-axis carriage_. Mostly because of the phrase in Tom's answer, _which can eventually hang caret_, which probably should be _which can eventually hang [the x-axis] carriage_  
> **username_6**: where did you find this under troubleshooting, I think Im having the same issue. Can't find what you are refereing to.  
> **username_4**: Found it in the A8 Operation instruction-1.1.pdf file provided on the SD card, page 66  

---

### Answer by username_1 on 2016-11-21. Score: 6

I assume you did everything according to the instructions but here is a checklist of what could be possibly wrong:

1. Friction - check if you can rotate/move parts without lot of resistance
2. Screws - check if screws on couplings are tight and they don't slide over a shaft or thread
3. Stepsticks - check if they are cooled properly and similar (as there are two of them)
4. Carriage nuts on threads - check if they do not slide out of their nests while [the x-axis] carriage goes up
5. Filament - check if filament unrolls without resistance which can eventually cause [the x-axis] carriage to hang.

IMO #2 and #3 are the most possible cause

[![Diagram of issues 1, 2 and 5](https://i.sstatic.net/4Hd33.png)](https://i.sstatic.net/4Hd33.png)

> **Comments:**
> **username_0**: `caret nut` is a new term for me.  
> **username_1**: well - here is top left elem (prusa i2) where such nut sits http://3dprinter.my/cart/images/Reprap%20Prusa%20i2%20Printed%20Parts%20Black.jpg more or less the same is in prusa i3  
> **username_2**: I don't think `caret nut` is a real word. It is probably a mistranslation.  
> **username_0**: With (2), I had the spindle and the thread pressed tight together, the coupling was unable to bend...  
> **username_5**: @username_2 - I think `caret` should actually be `carriage`  
> **username_1**: @username_0 the issue is to have screws properly screwed  
> **username_5**: @username_1 - Would you happen to have a source for the image and the checklist? Just to check the intended meaning of `caret`. I have downloaded the Anet [troubleshooting guide](http://www.anet3d.com/English/Technical_Support/Customer_Service/109.html) but it was not mentioned in that document.  
> **username_1**: @username_5 checklist and image source, both come from my head :) let's forget this caret thing, I've just changed it in my ans  

---

### Answer by username_4 on 2019-01-20. Score: 0

From <http://3daddict.com/anet-3d-printer-common-mistakes-fix/>

The motor shaft and the threading rod must have space between them in the flexible coupler.

That means unlocking the coupler from the motor shaft and moving it up a bit, in the end the threaded rod nearly touches the printer top hole instead of having like a 1cm gap.
This will allow the coupler to flex, and thus should handle small misalignments of the brass nut.

That's about point 2 of @username_1 answer, but before locking the screws, make sure to have empty space between rod and motor shaft


---

