<p>From your video, it sounds to me as though the stepper motor is fighting against the bed movement. That would indicate to me the bed rails on the X-axis are not square to the bed movement, which would cause binding of the linear bearings on the bed.</p>

<p>To see if this is the issue, loosen the threaded rods in all six places (three placed times two rods). Loosen the belt tensioner so it is not causing any issues. Then see how the bed moves. If the bed is freed up, tighten the nuts on the threaded rods two at a time on the same plane (each plate of the frame). At each tightening, ensure the bed continues to move freely. Measure the distance as accurately as possible to ensure the frame continues to stay square and are parallel to each other. Once you have tightened all of the nuts on the threaded rod, then re-tighten the belt tensioner.</p>

<p>If none of this solves it, it could also be an issue with your linear bearings. If your Anet A8 is a Chinesium clone, the bearings are not what I'd call "top notch". I replaced mine with Igus Drylin bearings and have not regretted the $10 investment. There are other printed options you could go with as well, which you can find on <a href="https://www.thingiverse.com/search?q=linear+bearings&amp;dwh=965c1f9d491dd88" rel="nofollow noreferrer">thingiverse.com</a>.</p>

CC BY-SA 4.0
2018-12-23T14:36:45.390Z
2018-12-23T14:36:45.390Z
Pᴀᴜʟsᴛᴇʀ2
<p>With the second video and the photos I could identify, that the sound in part stems from the belt:</p>

<ul>
<li>It is too loose and swing <strong>sideways</strong> as it pulls.</li>
</ul>

<p>Tighten the belt till it sounds <em>at least</em> like a C<sub>3</sub> or D<sub>3</sub> (130/146 Hz) and possibly higher. My Ender3 is <em>tuned</em> to something like A<sub>3</sub> (220 Hz). It should be tight and show no sideways swinging on using the motor.</p>

<p>It seems also, that the belt is not running parallel but skewed - that would induce sideways swing too. Make sure the axis of the motor and the pully are parallel and the mounting point of the carriage is not sideways of the belt path, as this will rub the belt against the gear.</p>

CC BY-SA 4.0
2018-12-23T13:55:11.883Z
Where at the belt should I pull? I measure and pull on the longer end, i.e. the one directly connecting the tensioner and the motor, not the one where the carriage is mounted.
Till B
CC BY-SA 4.0
2018-12-23T13:57:22.570Z
I test my long arm, with the carriage at the far side. it is not *exact*, it is just what I like to hear for my tension: both up and low close to one another and around A3
Trish
CC BY-SA 4.0
2018-12-23T13:48:16.600Z
2018-12-23T13:56:46.453Z
2018-12-23T13:56:46.453Z
Trish
<p>I have an Anet A8 and I currently try to improve the y-axis (with a tensioner and a frame to support the structure). Now after I dis- and reassembled the y-axis, I get a loud rattling noise when homing the y-axis (and also when moving it stepwise from within the firmware). After the rattling goes on for a second or two, the printer halts and asks to reset. During the rattling, the print bed moves much slower. It appears to only rattle at the end of the axis, close to the endstop, however the point at which it starts to rattle appears random.</p>

<p>I tried a tighter and looser belt and aligning the frame. When moving the bed manually, it does require some force, but it does not appear to be tighter at the back side of the axis. Also nothing seems to block the path of movement.</p>

<p>I noticed that with a tighter belt the rattling starts only closer to the end stop, however it appears like I have to overtighten it to work properly. I got it to hit the end stop this way without halting, however it still produced the rattling sound. Also the y-stepper motor made a high pitched humming noise after this operation.</p>

<p>What else could I check or do about it?</p>

<p>This is a video showing the print bed with the rattling sound:
<a href="https://www.youtube.com/watch?v=H0Xhz2GtUYQ" rel="nofollow noreferrer">https://www.youtube.com/watch?v=H0Xhz2GtUYQ</a></p>

<p>View from below:
<a href="https://youtu.be/oTEuZUWD0ZM" rel="nofollow noreferrer">https://youtu.be/oTEuZUWD0ZM</a></p>

<p>This is the motor mount:
<a href="https://i.sstatic.net/7xmJM.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/7xmJM.jpg" alt="enter image description here"></a></p>

<p>And this is the tensioner with the support frame:
<a href="https://i.sstatic.net/5wz8u.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/5wz8u.jpg" alt="enter image description here"></a></p>

CC BY-SA 4.0
2018-12-23T13:26:41.690Z
I added a video of the setup and the sound. The belt does not appear to rub on the frame. When pulling the belt, I get various sounds, like I said, I tried different belt tensions.
Till B
CC BY-SA 4.0
2018-12-23T13:44:30.320Z
Added the pictures. Also I noticed that with a tighter belt, I can control the rattling, however it does not disappear. I added a section on this in the question.
Till B
CC BY-SA 4.0
2018-12-23T13:46:50.247Z
The belt makes  noise like a guitar string. Currently it is at around 100Hz. Like I said, I tried various tensions. At this tightness the rattling is less that with a looser belt.
Till B
CC BY-SA 4.0
2018-12-23T13:54:31.163Z
With the original Anet A8 kit.
Till B
CC BY-SA 4.0
2018-12-23T14:06:40.703Z
Let us [continue this discussion in chat](https://chat.stackexchange.com/rooms/87423/discussion-between-trish-and-till-b).
Trish
CC BY-SA 4.0
2018-12-24T20:33:47.810Z
The upper and lower part of the belt need to be parallel to the bed, the standard attachment is a design flaw, see a correct attachment [here](https://www.thingiverse.com/thing:1648888).
0scar
<anet-a8><y-axis><belt>
Failing y-axis home with loud rattling
Till B
# Failing y-axis home with loud rattling

(Asked by: username_0 on 2018-12-23)

I have an Anet A8 and I currently try to improve the y-axis (with a tensioner and a frame to support the structure). Now after I dis- and reassembled the y-axis, I get a loud rattling noise when homing the y-axis (and also when moving it stepwise from within the firmware). After the rattling goes on for a second or two, the printer halts and asks to reset. During the rattling, the print bed moves much slower. It appears to only rattle at the end of the axis, close to the endstop, however the point at which it starts to rattle appears random.

I tried a tighter and looser belt and aligning the frame. When moving the bed manually, it does require some force, but it does not appear to be tighter at the back side of the axis. Also nothing seems to block the path of movement.

I noticed that with a tighter belt the rattling starts only closer to the end stop, however it appears like I have to overtighten it to work properly. I got it to hit the end stop this way without halting, however it still produced the rattling sound. Also the y-stepper motor made a high pitched humming noise after this operation.

What else could I check or do about it?

This is a video showing the print bed with the rattling sound:
<https://www.youtube.com/watch?v=H0Xhz2GtUYQ>

View from below:
<https://youtu.be/oTEuZUWD0ZM>

This is the motor mount:
[![enter image description here](https://i.sstatic.net/7xmJM.jpg)](https://i.sstatic.net/7xmJM.jpg)

And this is the tensioner with the support frame:
[![enter image description here](https://i.sstatic.net/5wz8u.jpg)](https://i.sstatic.net/5wz8u.jpg)

**Tags:** anet-a8, y-axis, belt
> **Comments:**
> **username_0**: I added a video of the setup and the sound. The belt does not appear to rub on the frame. When pulling the belt, I get various sounds, like I said, I tried different belt tensions.  
> **username_0**: Added the pictures. Also I noticed that with a tighter belt, I can control the rattling, however it does not disappear. I added a section on this in the question.  
> **username_0**: The belt makes  noise like a guitar string. Currently it is at around 100Hz. Like I said, I tried various tensions. At this tightness the rattling is less that with a looser belt.  
> **username_0**: With the original Anet A8 kit.  
> **username_1**: Let us [continue this discussion in chat](https://chat.stackexchange.com/rooms/87423/discussion-between-trish-and-till-b).  
> **username_2**: The upper and lower part of the belt need to be parallel to the bed, the standard attachment is a design flaw, see a correct attachment [here](https://www.thingiverse.com/thing:1648888).  

---

## 2 answers

### Answer by username_3 on 2018-12-23. Score: 1

From your video, it sounds to me as though the stepper motor is fighting against the bed movement. That would indicate to me the bed rails on the X-axis are not square to the bed movement, which would cause binding of the linear bearings on the bed.

To see if this is the issue, loosen the threaded rods in all six places (three placed times two rods). Loosen the belt tensioner so it is not causing any issues. Then see how the bed moves. If the bed is freed up, tighten the nuts on the threaded rods two at a time on the same plane (each plate of the frame). At each tightening, ensure the bed continues to move freely. Measure the distance as accurately as possible to ensure the frame continues to stay square and are parallel to each other. Once you have tightened all of the nuts on the threaded rod, then re-tighten the belt tensioner.

If none of this solves it, it could also be an issue with your linear bearings. If your Anet A8 is a Chinesium clone, the bearings are not what I'd call "top notch". I replaced mine with Igus Drylin bearings and have not regretted the $10 investment. There are other printed options you could go with as well, which you can find on [thingiverse.com](https://www.thingiverse.com/search?q=linear+bearings&dwh=965c1f9d491dd88).


---

### Answer by username_1 on 2018-12-23. Score: 0

With the second video and the photos I could identify, that the sound in part stems from the belt:

* It is too loose and swing **sideways** as it pulls.

Tighten the belt till it sounds *at least* like a C3 or D3 (130/146 Hz) and possibly higher. My Ender3 is *tuned* to something like A3 (220 Hz). It should be tight and show no sideways swinging on using the motor.

It seems also, that the belt is not running parallel but skewed - that would induce sideways swing too. Make sure the axis of the motor and the pully are parallel and the mounting point of the carriage is not sideways of the belt path, as this will rub the belt against the gear.

> **Comments:**
> **username_0**: Where at the belt should I pull? I measure and pull on the longer end, i.e. the one directly connecting the tensioner and the motor, not the one where the carriage is mounted.  
> **username_1**: I test my long arm, with the carriage at the far side. it is not *exact*, it is just what I like to hear for my tension: both up and low close to one another and around A3  

---

