Anet A8 Y-belt tensioner V2

by YoshiCat, published

Anet A8 Y-belt tensioner V2 by YoshiCat Jan 8, 2017
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Add new file for part V2_2, it is a little longer (V2_2L) for a better fit for the shorter original belt.
Add new file for part 3 to made it stronger, now V2_3 ( old one seems to break with some people ) Part 3 needs to be print with 100% infill.
Add 2 new V2 files with improvement of the parts 1 and 2. (See last photo)
This new version makes the construction more rigid
If you use the new parts you will need a longer screw for the belt tension

This tensioner can be installed without any modification on the a8 and makes it easy to tighten the belt.
For mounting on the frame are four M3 x 18 screws and four M3 nuts needed. For the tension you need one M3 x 18 screw and 1 M3 locknut. And two more M3 x 20 with locknut to mount the bearings and the pivot point.
I used three M3 washers on the bearings, one between the bearings and the other two between the bearing and the frame.

Print Settings


Anet A8






Wall 1.6

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What about backlash when tension oscillate ?

I can't get second version to work, screw is not parallel to rest of construction so nut don't want to work

Try to print part V2_2L this will solve the short belt problem

I have the same issue. I like this design, but that angle in the bolt makes it tough to use.

Comments deleted.

Try to print part V2_2L this will solve the short belt problem

Then, i think your belt is not long enough. With a longer belt it will be parallel.

Comments deleted.

The square pegs were not compatible with my A8, but a file, a sharp knife, and the rest fits perfectly. Thank you

Update - after 12 hours use it broke.. ah well, it was good while it worked

Use more infill, mine still works after 8 months

It broke on the pulley holder, where the right angle section with the tensioner screw plate joins the 2 sides. I will try again with 100% infill for that part, but will also try to edit and fatten the spot that's weakest for me - as I said, I like the design, clean, simple and works well, its just that one spot seems a little weak under load. I liked it enough to try it again :)

Heres a photo - https://imgur.com/a/qcmn4 showing where it broke - it was an early print, still learning the ropes.

Just upload a stronger version off the pulley holder, print it with 100% infill and let me know if it's ok.

Gave it a heavy 3 week workout, its handling the load beautiffully (and looks better than the modified one I did in Tinkercad )


I will look at it to made it stronger.

Wobling comes from z-axis

What about wobb wobbling on this model ? as all others ?

Not sure why, but this brace from Leo N does not fit my bed.. It is a factory Anet A8 120x120x140 dimensions. I just can't seem to find this on thingiverse.. Any help or advise would be appreciated ..

There is a cura setting that automatically reduces large objects so they fit on the table. After loading, check if the size is still 100% and if not change this back to 100%.

thank you, I am new to this and appreciate the help.

By the way, you need to turn the brace diagonal over the bed to print it.

Yes, that worked...! I want to say thank you, this was the most important upgrade for my unit and has resolved some of the issues I was experiencing with table movement(shaking). Your belt tension bracket works great.. thanks again..

great design,i love it !
can i use it with the 16 teeth pulley?

Did you use the 16 tooth pulleys and do they work?

Maybe you can try the remake from Butchja


Anet A8 Y-belt Toothed Idler Tensioner
by butchja

i´ve printed this days and it works with your version too :)

Happy tot hear that, enjoy.

No idea, don't have the 16 teeth pulley.

I printed this today and it fits perfect! Another great mod for my Anet A8 ;)
Thx for sharing!

Yoshicat, can you tell me which frame brace you used in the picture? I would like to print one that is compatible with your Y tensioner. Thanks for uploading this part.

Anet A8 Front Frame Brace
by Leo_N

Installed this today along with another tensioner and fiddled around with my printer, prints are greatly improved, thanks for sharing!

Do not feed that gloomy engineer. I like your design and I remixed it. Because it is perfect for my printer.

I have one suggestion: Could you add some tolerance compensation to this part. It was hard to me to put it into my frame. I mostly use 0.1mm or more on each side to generate a clearance fit.

I give it 0.1 tollerance and on my frame it was fitting fine, could it be the settings of your printer?

I think the TronXY uses a different thickness of acrylics for its tensioner (7mm), So I found that I had to take off about .8mm (aka the whole wall) of the inside of each stud (the left sides of the right studs and the right side of the left studs). The outsides and top+bottoms were fine.

BTW, I didn't have M3x18s, the TronXY comes with M3x20s. I just used a nut as washer on the outside.

The pulley holder and adjustment system here http://www.thingiverse.com/thing:2023359 is far better and simpler !

Belt tensioning modification for Anet A8
by riki92

It's not better and definitely not simpler since it requires you to screw your printer down to a board.

There are here several belt tensioners. So if you find another better, it is free to make and use them.
Everyone has their own idea to solve something so, choose a design yourself and enjoy it.



Indeed but the rule in engineering is first to do a search to see how others have done it (belt and pulleys have been used for a few hundred years) and at least try to improve on it, not do something inferior. This is not "fashion" or "philosophy". No need to reinvent the wheel and often end up with a square one :)

@MKSA: To justify, there is a immediately visible design flaw in the thing You mentioned - the belt is not straightly tensioned ;)

Tell it to the guy who designed it then and let's see :)