<p>You may not need to adjust the tension, but you may nevertheless want to measure the belt tension, at least to ensure it's not too tight: the shaft on stepper motor has limitations. For example, NEMA 17 may have 30 N maximum tension then the belt is located at 17 mm from the motor face.</p>
<p>In that case, no need to buy a tool, you can use an audio app showing the frequency spectrum and then you pluck the belt. The lowest frequency peak can be related to the tension as explained here:</p>
<p><a href="https://benchtopmachineshop.blogspot.com/2019/04/printer-belt-tension.html" rel="nofollow noreferrer">https://benchtopmachineshop.blogspot.com/2019/04/printer-belt-tension.html</a></p>
<p>For GT2 belts and 27 N tension, assuming the distance between belt and motor face is 10 mm, the relation is</p>
<p><span class="math-container">$$f [\text{Hz}] = \frac{28531 \frac{ \text mm}{\text s}}{length [\text{mm}]}$$</span></p>
<p>Be aware that by plucking the belt you will excite the higher harmonics more than the base harmonic, therefore identifying the lowest frequency may take some time and multiple tries. You should display the frequency spectrum as &quot;waterfall&quot;. The app &quot;Spectroid&quot; for Android has it.</p>
<p>If the distance between middle of the belt width and motor face is twice the value assumed (for example, 20 mm instead of 10 mm), the belt tension should be halved (based on an inverse relationship).</p>
<p>For those interested in alternative approaches, <a href="https://prorifi3d.com/pages/how-to-tune-your-timing-belt" rel="nofollow noreferrer">this page</a> calculates the belt tension based on the datasheet of the belts, but <strong>it completely ignores the maximum load tolerated by the motors</strong>. So you can follow their directions but do not exceed the values recommended by the motors. The calculations mentioned there are discussed also on the following video:</p>
<p><div class="youtube-embed"><div>
                <iframe width="640px" height="395px" src="https://www.youtube.com/embed/gB8m6_eGShs?start=0"></iframe>
            </div></div></p>

CC BY-SA 4.0
2021-10-12T21:27:14.453Z
heh, tuning your belts by sound? I always was going for a *nice* sound, not a specific frequency, but this is gold!
Trish
CC BY-SA 4.0
2021-10-05T15:14:54.180Z
2024-02-26T14:26:11.187Z
2024-02-26T14:26:11.187Z
FarO
<p>People are using this</p>
<p><a href="https://i.sstatic.net/zA3d9.png" rel="nofollow noreferrer" title="Clothpin springs repurposed into a makeshift belt tensioner"><img src="https://i.sstatic.net/zA3d9.png" alt="Clothpin springs repurposed into a makeshift belt tensioner" title="Clothpin springs repurposed into a makeshift belt tensioner" /></a></p>
<p>to tighten the belt but I would totally agree with @Tom - there is no need to use such devices or gauges and your problem lies in stepsticks current.</p>
<p>It would be also problem with endstops so PCB doesn't know it's time to stop :)</p>

CC BY-SA 3.0
2016-04-12T10:01:50.997Z
Can you explain how this belt tensioner (if that is a correct name for it) works?
kamuro
CC BY-SA 3.0
2016-04-12T10:03:37.993Z
@kamuro it's just a spring that you put on the belt. It isn't really a tensioner (you still have to pull the belt tight somehow) but it helps keep the tension consistent.
Tom van der Zanden
CC BY-SA 3.0
2016-04-12T10:05:32.667Z
In the meantime I found the idea by image searching 'belt tensioner', too: http://www.iheartrobotics.com/2009/11/timing-belt-tensioner.html The search also turned up lots of other interesting tensioning designs used in various other (industrial) sectors, too. Sweet inspiration ;)
kamuro
CC BY-SA 3.0
2016-04-12T10:09:17.150Z
On another note, I would assume that the current of the stepsticks also is a less important effect. I would take a look at the axis motion friction first. Parallelity of rods first, if the strength of the effect is varying depending on the position.
kamuro
CC BY-SA 3.0
2016-04-12T11:32:55.023Z
Well - depending on drive train design - this effect can also apear because of low wrap angle. Which means that timing belt surrounds a pulley not enough.
darth pixel
CC BY-SA 3.0
2016-04-12T11:38:26.690Z
@kamuro as TvdZ said - it's not real tensioner it's more like laundry clip but it works fine so why not to give it a try :) But be careful it cost even $2 (as a "tensioner") but if you buy 10 laundry clips you will get 10 "tensioners" for half od dollar.
darth pixel
CC BY-SA 3.0
2016-04-12T11:41:43.077Z
I didn't want to diminish the idea of using a belt tensioner at all, sorry if it came across like that.
kamuro
CC BY-SA 3.0
2016-04-12T11:48:44.807Z
@kamuro not at all :)
darth pixel
CC BY-SA 3.0
2016-04-12T14:35:00.617Z
I would advise AGAINST using that kind of belt tensioner. Springs anywhere in your drivetrain add ringing at corners. The last thing you want in a precision motion control device is stretchy belts.
Ryan Carlyle
CC BY-SA 3.0
2016-04-12T14:44:04.870Z
@RyanCarlyle Are you sure about that? It seems these spring-type tensioners are used in "professional" printers (Ultimaker comes to mind) and even some mass-market 2D printers. In any case, this problem is likely not about belt tension.
Tom van der Zanden
CC BY-SA 3.0
2016-04-12T16:45:51.477Z
@RyanCarlyle don't you think these tensioners are just compensate sudden de/acceleration. Belt itself is not stretchy, its dimension change during acceleration only then it gets back to normal so counting whole amount of the movement dimension doesn't change a bit. Timing belt itself is doing the same by its nature isn't it?
darth pixel
CC BY-SA 3.0
2016-04-12T17:01:19.850Z
Yes, I'm sure. A spring-tensioner is better than a loose belt, which is why some Ultimakers have them (particularly since getting even belt tension on a UM gantry is hard) but a rigid tensioner (adjust and lock) is superior to a spring tensioner. We use fiberglass-core and aramid-core timing belts in 3D printers for a reason, because they're as stiff as possible in tension. Spring tensioners makes the belt more stretchy. Specifically, when you turn a corner at positive velocity (jerk>0) any springiness in the drivetrain causes increased overshoot and therefore ringing.
Ryan Carlyle
CC BY-SA 3.0
2016-04-12T17:25:55.450Z
Should add here that if the clothes-pin spring tensioner is nearly fully extended, it will be fairly stiff, because the geometry creates a force multiplier to make the spring apply a lot more tension. (EG see http://physicsbuzz.physicscentral.com/2015/04/physics-life-hack-number-3-getting-your.html) But if the spring tensioner is taking up a lot of slack and is not extended, it will add springiness to the belt.
Ryan Carlyle
CC BY-SA 4.0
2016-04-12T09:14:42.250Z
2024-02-27T19:04:04.697Z
2024-02-27T19:04:04.697Z
darth pixel
<p><em>Added for reference.</em> To my understanding, especially if you run multiple identical printers, having the same belt tension on all of them is essential to getting accurate and consistent results. The effects of overly loose or overly tight belts have been demonstrated in a <a href="https://youtu.be/_m9TTzEh5xM?si=W4xKfKc_XZGPQWk6&amp;t=145" rel="nofollow noreferrer">YouTube video by CHEP</a>.</p>
<p>As mentioned in the comments above, a frequency analyser on a smartphone can be used, a web-based analyser is available at <a href="https://belt.connect.prusa3d.com/" rel="nofollow noreferrer">belt.connect.prusa3d.com</a>. Additionally, the article <a href="https://help.prusa3d.com/article/adjusting-belt-tension-mk3-mk3s-mk3s-mk4_112380" rel="nofollow noreferrer">Adjusting belt tension (MK3/MK3S/MK3S+/MK4)</a> explains the concepts and steps that can be taken for belt tensioning.</p>
<p><a href="https://i.sstatic.net/GFhnvm.png" rel="nofollow noreferrer" title="Photo of the web-based Prusa Belt (Beta) frequency analyser on a smartphone"><img src="https://i.sstatic.net/GFhnvm.png" alt="Photo of the web-based Prusa Belt (Beta) frequency analyser on a smartphone" title="Photo of the web-based Prusa Belt (Beta) frequency analyser on a smartphone" /></a></p>
<p>Also, a simple belt tension measurement tool called <a href="https://www.printables.com/model/46639-tension-meter-for-the-gt2-belts-of-i3-mk3s-or-prus" rel="nofollow noreferrer">Tension Meter for the GT2 belts of i3 MK3S+ or Prusa MINI+</a> that can easily be printed has been published by Prusament.</p>
<p><a href="https://i.sstatic.net/LKAhxm.jpg" rel="nofollow noreferrer" title="Tension Meter for the GT2 belts of i3 MK3S+ or Prusa MINI+"><img src="https://i.sstatic.net/LKAhxm.jpg" alt="Tension Meter for the GT2 belts of i3 MK3S+ or Prusa MINI+" title="Tension Meter for the GT2 belts of i3 MK3S+ or Prusa MINI+" /></a></p>
<p>There is a similar printable model called <a href="https://www.thingiverse.com/thing:4731435" rel="nofollow noreferrer">True Open source tension meter for GT2 belts</a> by ChipCE.</p>
<p><a href="https://i.sstatic.net/05T5nm.png" rel="nofollow noreferrer" title="True Open source tension meter for GT2 belts"><img src="https://i.sstatic.net/05T5nm.png" alt="True Open source tension meter for GT2 belts" title="True Open source tension meter for GT2 belts" /></a></p>

CC BY-SA 4.0
2023-11-07T09:08:36.233Z
2023-11-07T14:46:12.457Z
2023-11-07T14:46:12.457Z
Bob Ortiz
<p>It's extremely unlikely that belt tension is actually your problem. I've never heard of anyone using a gauge to measure their belt tension. Typically you just pull your belt tight by hand so that it produces a low note when plucked. It's far more likely that you're experiencing shifts due to too high or too low stepper current.</p>

<p>Unless your belt is so loose that it easily skips over the pulley (which should be obvious without using a gauge) or so tight that it completely binds up (it would be impossible to get it that tight without some kind of superhuman force) it's definitely not the problem.</p>

CC BY-SA 3.0
2016-04-12T10:00:39.713Z
I've read of people using smartphone apps that calculate the belt tension by measuring the frequency of the plucked belt. If you (the TO) are completely lost and need any kind of confirmation this might  be a way to get it easily.
kamuro
CC BY-SA 3.0
2016-04-12T17:34:17.600Z
I used a spring scale (meant for fishing). But it's really not critical. Just make sure it's not skipping teeth on the pulley and you should be fine.
TextGeek
CC BY-SA 3.0
2016-04-12T18:42:32.517Z
I tensioned the belts of my delta printer equally tight solely based on their note when plucked. If you have an ear for music, that should be fairly straightfoward.
Tormod Haugene
CC BY-SA 3.0
2016-04-12T20:18:44.693Z
@kamuro thanks, will do if needed. Although now it seems not the issue.
Bashar Abdullah
CC BY-SA 3.0
2016-04-12T20:19:59.357Z
@TormodHaugene alright. Although now it seems unlikely this is the issue.
Bashar Abdullah
CC BY-SA 3.0
2016-04-12T20:24:21.600Z
@Tom van der Zanden Any tips how to know if this is stepper current problem?

I'll most likely end up opening separate thread for that. But it would be good to have more info.
Bashar Abdullah
CC BY-SA 3.0
2016-04-13T08:54:29.730Z
@BasharAbdullah your issue is one of possible signs of current problem :)
#1. Check resistor on your SS (right next to black central chip.
#2. There should be R200 or R100 so R=0.2 or 0.1
#3. Read current (I) value from motor label
#4. V = I * R * 8
#5. this is max voltage which should be set on SS
#6. set it and check if your printer works ok
#7. if not - reduce it 10..15% and chceck if this helps. you can repeat #7.
darth pixel
CC BY-SA 3.0
2016-04-14T06:51:56.687Z
@darthpixel thanks. I'm new to 3D printing really, so will try to tinker and see where I get :)
Bashar Abdullah
CC BY-SA 4.0
2023-11-10T12:45:38.460Z
Loose belt doesn't need to skip to cause print problems - it's one of most common causes of a very common problem with small layer shifts, resulting in awful surface of vertical walls.
SF.
CC BY-SA 4.0
2023-11-10T12:49:51.030Z
Also, the phone app is a great way to learn what sound is the "good tension". Once you learn it, forget the app and do it by ear. There's plenty of slack between "too tight" and "too loose" so don't sweat it about getting it perfect.
SF.
CC BY-SA 3.0
2016-04-12T07:45:06.353Z
2016-04-12T07:45:06.353Z
Tom van der Zanden
<p>I have a 3D printer that is going crazy with x-axis shift, and I need a tension gauge belt to measure the tension.</p>

<p>I've never used one before, and looking online, I can't tell which one would be the right fit.</p>

<p>Any ideas? What things should I look for?</p>

CC BY-SA 3.0
2016-04-12T14:35:37.590Z
What kind of printer is it? Most Cartesian printers that experience X-axis shift are having problems with fatigued electrical wiring to the X stepper or X endstop.
Ryan Carlyle
CC BY-SA 3.0
2016-04-12T20:17:22.923Z
@RyanCarlyle It's Cubicon. Not popular brand in West. Korean made. Supposed to be good. But soon after getting it, this started happening. Part of their troubleshooting suggested checking the belt
Bashar Abdullah
CC BY-SA 3.0
2016-04-13T02:04:23.947Z
Looks like a cartesian XY gantry printer, from a quick googling. If you can pluck the belt like Tom mentioned and get a low note, but still get X axis shifting, my next guess would be bad X motor or X endstop wiring.
Ryan Carlyle
<hardware><belt>
Which belt tension gauge do I need?
Bashar Abdullah
# Which belt tension gauge do I need?

(Asked by: username_0 on 2016-04-12)

I have a 3D printer that is going crazy with x-axis shift, and I need a tension gauge belt to measure the tension.

I've never used one before, and looking online, I can't tell which one would be the right fit.

Any ideas? What things should I look for?

**Tags:** hardware, belt

> **Comments:**
> **username_1**: What kind of printer is it? Most Cartesian printers that experience X-axis shift are having problems with fatigued electrical wiring to the X stepper or X endstop.  
> **username_0**: @username_1 It's Cubicon. Not popular brand in West. Korean made. Supposed to be good. But soon after getting it, this started happening. Part of their troubleshooting suggested checking the belt  
> **username_1**: Looks like a cartesian XY gantry printer, from a quick googling. If you can pluck the belt like Tom mentioned and get a low note, but still get X axis shifting, my next guess would be bad X motor or X endstop wiring.  

---

## 4 answers

### Answer by username_6 on 2016-04-12. Score: 6 | Accepted answer

It's extremely unlikely that belt tension is actually your problem. I've never heard of anyone using a gauge to measure their belt tension. Typically you just pull your belt tight by hand so that it produces a low note when plucked. It's far more likely that you're experiencing shifts due to too high or too low stepper current.

Unless your belt is so loose that it easily skips over the pulley (which should be obvious without using a gauge) or so tight that it completely binds up (it would be impossible to get it that tight without some kind of superhuman force) it's definitely not the problem.

> **Comments:**
> **username_5**: I've read of people using smartphone apps that calculate the belt tension by measuring the frequency of the plucked belt. If you (the TO) are completely lost and need any kind of confirmation this might  be a way to get it easily.  
> **username_8**: I used a spring scale (meant for fishing). But it's really not critical. Just make sure it's not skipping teeth on the pulley and you should be fine.  
> **username_9**: I tensioned the belts of my delta printer equally tight solely based on their note when plucked. If you have an ear for music, that should be fairly straightfoward.  
> **username_0**: @username_5 thanks, will do if needed. Although now it seems not the issue.  
> **username_0**: @username_9 alright. Although now it seems unlikely this is the issue.  
> **username_0**: @username_6 Any tips how to know if this is stepper current problem?  I'll most likely end up opening separate thread for that. But it would be good to have more info.  
> **username_4**: @username_0 your issue is one of possible signs of current problem :) #1. Check resistor on your SS (right next to black central chip. #2. There should be R200 or R100 so R=0.2 or 0.1 #3. Read current (I) value from motor label #4. V = I * R * 8 #5. this is max voltage which should be set on SS #6. set it and check if your printer works ok #7. if not - reduce it 10..15% and chceck if this helps. you can repeat #7.  
> **username_0**: @username_4 thanks. I'm new to 3D printing really, so will try to tinker and see where I get :)  
> **username_10**: Loose belt doesn't need to skip to cause print problems - it's one of most common causes of a very common problem with small layer shifts, resulting in awful surface of vertical walls.  
> **username_10**: Also, the phone app is a great way to learn what sound is the "good tension". Once you learn it, forget the app and do it by ear. There's plenty of slack between "too tight" and "too loose" so don't sweat it about getting it perfect.  

---

### Answer by username_2 on 2021-10-05. Score: 5

You may not need to adjust the tension, but you may nevertheless want to measure the belt tension, at least to ensure it's not too tight: the shaft on stepper motor has limitations. For example, NEMA 17 may have 30 N maximum tension then the belt is located at 17 mm from the motor face.

In that case, no need to buy a tool, you can use an audio app showing the frequency spectrum and then you pluck the belt. The lowest frequency peak can be related to the tension as explained here:

<https://benchtopmachineshop.blogspot.com/2019/04/printer-belt-tension.html>

For GT2 belts and 27 N tension, assuming the distance between belt and motor face is 10 mm, the relation is

$$f [\text{Hz}] = \frac{28531 \frac{ \text mm}{\text s}}{length [\text{mm}]}$$

Be aware that by plucking the belt you will excite the higher harmonics more than the base harmonic, therefore identifying the lowest frequency may take some time and multiple tries. You should display the frequency spectrum as "waterfall". The app "Spectroid" for Android has it.

If the distance between middle of the belt width and motor face is twice the value assumed (for example, 20 mm instead of 10 mm), the belt tension should be halved (based on an inverse relationship).

For those interested in alternative approaches, [this page](https://prorifi3d.com/pages/how-to-tune-your-timing-belt) calculates the belt tension based on the datasheet of the belts, but **it completely ignores the maximum load tolerated by the motors**. So you can follow their directions but do not exceed the values recommended by the motors. The calculations mentioned there are discussed also on the following video:

> **Comments:**
> **username_3**: heh, tuning your belts by sound? I always was going for a *nice* sound, not a specific frequency, but this is gold!  

---

### Answer by username_4 on 2016-04-12. Score: 1

People are using this

[![Clothpin springs repurposed into a makeshift belt tensioner](https://i.sstatic.net/zA3d9.png "Clothpin springs repurposed into a makeshift belt tensioner")](https://i.sstatic.net/zA3d9.png "Clothpin springs repurposed into a makeshift belt tensioner")

to tighten the belt but I would totally agree with @Tom - there is no need to use such devices or gauges and your problem lies in stepsticks current.

It would be also problem with endstops so PCB doesn't know it's time to stop :)

> **Comments:**
> **username_5**: Can you explain how this belt tensioner (if that is a correct name for it) works?  
> **username_6**: @username_5 it's just a spring that you put on the belt. It isn't really a tensioner (you still have to pull the belt tight somehow) but it helps keep the tension consistent.  
> **username_5**: In the meantime I found the idea by image searching 'belt tensioner', too: http://www.iheartrobotics.com/2009/11/timing-belt-tensioner.html The search also turned up lots of other interesting tensioning designs used in various other (industrial) sectors, too. Sweet inspiration ;)  
> **username_5**: On another note, I would assume that the current of the stepsticks also is a less important effect. I would take a look at the axis motion friction first. Parallelity of rods first, if the strength of the effect is varying depending on the position.  
> **username_4**: Well - depending on drive train design - this effect can also apear because of low wrap angle. Which means that timing belt surrounds a pulley not enough.  
> **username_4**: @username_5 as TvdZ said - it's not real tensioner it's more like laundry clip but it works fine so why not to give it a try :) But be careful it cost even $2 (as a "tensioner") but if you buy 10 laundry clips you will get 10 "tensioners" for half od dollar.  
> **username_5**: I didn't want to diminish the idea of using a belt tensioner at all, sorry if it came across like that.  
> **username_4**: @username_5 not at all :)  
> **username_1**: I would advise AGAINST using that kind of belt tensioner. Springs anywhere in your drivetrain add ringing at corners. The last thing you want in a precision motion control device is stretchy belts.  
> **username_6**: @username_1 Are you sure about that? It seems these spring-type tensioners are used in "professional" printers (Ultimaker comes to mind) and even some mass-market 2D printers. In any case, this problem is likely not about belt tension.  
> **username_4**: @username_1 don't you think these tensioners are just compensate sudden de/acceleration. Belt itself is not stretchy, its dimension change during acceleration only then it gets back to normal so counting whole amount of the movement dimension doesn't change a bit. Timing belt itself is doing the same by its nature isn't it?  
> **username_1**: Yes, I'm sure. A spring-tensioner is better than a loose belt, which is why some Ultimakers have them (particularly since getting even belt tension on a UM gantry is hard) but a rigid tensioner (adjust and lock) is superior to a spring tensioner. We use fiberglass-core and aramid-core timing belts in 3D printers for a reason, because they're as stiff as possible in tension. Spring tensioners makes the belt more stretchy. Specifically, when you turn a corner at positive velocity (jerk>0) any springiness in the drivetrain causes increased overshoot and therefore ringing.  
> **username_1**: Should add here that if the clothes-pin spring tensioner is nearly fully extended, it will be fairly stiff, because the geometry creates a force multiplier to make the spring apply a lot more tension. (EG see http://physicsbuzz.physicscentral.com/2015/04/physics-life-hack-number-3-getting-your.html) But if the spring tensioner is taking up a lot of slack and is not extended, it will add springiness to the belt.  

---

### Answer by username_7 on 2023-11-07. Score: 0

*Added for reference.* To my understanding, especially if you run multiple identical printers, having the same belt tension on all of them is essential to getting accurate and consistent results. The effects of overly loose or overly tight belts have been demonstrated in a [YouTube video by CHEP](https://youtu.be/_m9TTzEh5xM?si=W4xKfKc_XZGPQWk6&t=145).

As mentioned in the comments above, a frequency analyser on a smartphone can be used, a web-based analyser is available at [belt.connect.prusa3d.com](https://belt.connect.prusa3d.com/). Additionally, the article [Adjusting belt tension (MK3/MK3S/MK3S+/MK4)](https://help.prusa3d.com/article/adjusting-belt-tension-mk3-mk3s-mk3s-mk4_112380) explains the concepts and steps that can be taken for belt tensioning.

[![Photo of the web-based Prusa Belt (Beta) frequency analyser on a smartphone](https://i.sstatic.net/GFhnvm.png "Photo of the web-based Prusa Belt (Beta) frequency analyser on a smartphone")](https://i.sstatic.net/GFhnvm.png "Photo of the web-based Prusa Belt (Beta) frequency analyser on a smartphone")

Also, a simple belt tension measurement tool called [Tension Meter for the GT2 belts of i3 MK3S+ or Prusa MINI+](https://www.printables.com/model/46639-tension-meter-for-the-gt2-belts-of-i3-mk3s-or-prus) that can easily be printed has been published by Prusament.

[![Tension Meter for the GT2 belts of i3 MK3S+ or Prusa MINI+](https://i.sstatic.net/LKAhxm.jpg "Tension Meter for the GT2 belts of i3 MK3S+ or Prusa MINI+")](https://i.sstatic.net/LKAhxm.jpg "Tension Meter for the GT2 belts of i3 MK3S+ or Prusa MINI+")

There is a similar printable model called [True Open source tension meter for GT2 belts](https://www.thingiverse.com/thing:4731435) by ChipCE.

[![True Open source tension meter for GT2 belts](https://i.sstatic.net/05T5nm.png "True Open source tension meter for GT2 belts")](https://i.sstatic.net/05T5nm.png "True Open source tension meter for GT2 belts")


---

