Y-axis rework for Anet A8

by matsekberg Jan 18, 2017
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This is awesome! Such an improvement on the wafty belt tensioning setup that is supplied.

This has fixed the bowing of the frame for my A8 and allowed me to get the desired belt tension for better print finish.

Thank you!

diseño muy inteligente,

Fantastic work, thanks for this!

I did this upgrade and found it to be very effective. There's no need for the rods to be metric. I used 1/4-20 threaded rod from my neighborhood hardware. $1.50

Where did you get your toothed idler?

Hey man, thx for your work. I've tried to open the SCAD file in order to enlarge the holes for an 8 mm rod but it's not rendering the motor mount part.

This code caught my attention

module original() {
union() {

that file doesn't exist. I wonder if this is the issue.

Thx a lot, it's a great design

I'd like to add my congratulations on a design well done. I've only had my A8 for two months now and I've gone through several different designs for x & y axis tension devices. Most of them put way too much strain on the acrylic panels before you have enough tension. This printed first time and installed with no issues at all. My print quality improved visibly and it solid enough that I'm not worried about needing to print replacement parts when something breaks. I did do a slight modification to the front mount that allows it to be printed without needing support. I removed the slot to bolt down to a surface and made the rod holes go through the mount which lets you get rid of the extensions and yields a flat surface to build up from. The forces are still distributed by the nuts onto the face of the mount so it yields the same functionality without need to use supports which I still have trouble with since I only have one extruder and hot end.

This is by far my favorite Anet A8 upgrade and I appreciate your sharing it. Any chance you'd share what you're using for your x axis?

BTW: I used blue locktite on all the nuts and they've held in place perfectly. No need for nylon lock nuts.

Hey man, this looks awesome! I've printed some of the parts, but the rods i have are a bit bigger. I wonder if it's possible for you to share the originals? i dont want to destroy it using meshmixer . thx a lot!

Is it possibile to have the cad source file? I want to make a rework for my customized A8 and working on stl is not the best thing
Thank you for your design

Has anyone tried to rework this for the original pruse I3?

Hello, i really like your design, but could you please add a motor dampener version, like in here? https://www.thingiverse.com/thing:2477814

Y-axis rework for Anet A8 with 8mm screws

I'm using this thing for month, and i must say, it's amazing.
There is just a little problem, every few printing hours one of the nuts rattles loose and makes really bad noise.
I've addresses that by replacing all nuts with nylon locknuts.

loctite will solve your problem as well.

even small amounts of loctite have been known to cause stress fractures in acrylic. Especially at the points used (screw/bolt holes).
be careful getting ANY on acrylic... or plastic in general

Hey you all,

first i like to say thanks to all your affords, this is a very good design and i also think its a must have. All others are fine but not perfect.

Theres one thing i wanted to ask, maybe someone already done it but didnt publish it.

I realy like the design of the big front and back brase.

Front: https://www.thingiverse.com/thing:2397219
Back: https://www.thingiverse.com/thing:1430727

I just like the look of those, so a wanted to make a version of the front and Back that already have your design in it. I just dont know how.
Did anybody do this or know somebody that did?

Thank you in advance

Anet A8 - Front Frame Brace with Mounting Holes
Frame brace for Anet A8
by Simhopp
Anet A8 Frame Braces w/Y-Axis Belt Tension Rods

The idea behind this thing is being an alternative to the frame braces that are just distributing the forces to the outermost threaded rods.
This design takes care of the force needed to keep the belt tensioned and leaves little or no stress in the frame.
I would be very surprised if a combo should improve the prints.

Put your money on other things like clamping the frame to a sturdy base, or releasing the strain from the vertical threaded rods by printing a new X-belt tensioner.

Guys, how you do with axis y endstop after install this upgrade???

The issue seems to be that the Y_belt_bedmount_mount_w_offset.stl hits Y-axis_motor2.stl with or without the nut and washer preventing the Y axis limit switch from being actuated. My solution was to remove the nuts completely from the Y-axis_motor2.stl mount and with an exacto knife cut a very small notch in the left rod mount of Y-axis_motor2.stl so that Y_belt_bedmount_mount_w_offset.stl clears the mount as the bed homes. It doesn't take much and be very careful not to remove too much material.

Did you made it work?

Just the "must make" upgrade !
Printed 2 days ago, first print with it today, and... whaou !

"Save a lot of filament, frame isn't "working" or "used" to take or give back Y-forces, ..." I was seduced

Just a word : you're a great designer ! No need to sand, cut, drill, everything fit perfectly, just have to drill what you said to, and... that's it !
Everything fits, clips, takes place, so... congratulations !

And because anything can't be perfect ^^ : the smallest threated rod could be 3 or 4 mm longer ;)

Oh, and I have to drill the front support a bit and heat up the nuts (see photo) but... that's because I wanted to use back stock's screws ;)

Love the design, it took me a while to sort it out but it looks like it is working brilliantly now. I also upgraded the belt to a fibreglass reinforced one (GT2), I think the toothing may be different as one of my test prints has come out elongated (some further calibration to be done).

I've added some pictures and a description to the 'I Made One' section along with some pictures of how I mounted the belt to the H plate.

For those that were wondering!

Edit: Yep the GT2 belt had different teeth width (pitch?) so had to change the steps/mm for Y axis to 80, this fixed a lot of issues. There were no additional changes required as a result of this mod being installed.

Question: The assembly instructions state:
"Note that the belt mount under the bed will be removed completely since it is too bulky. You need to make a clamp of 1-2 mm metal with two holes matching the holes where the original belt was. Clamp the belt between the metal clamp and the bed with two screws and a nut."

But it looks like there are (now?) printable pieces that can be used to attach the belt under the H-carriage, is that correct? If so, can these be printed in PLA or should they be ABS due to their proximity to the hotbed?

I just finished installing this mod, all printed in PLA. Belt attaches to the H plate, not the bed, so no need for ABS.

Thanks for the mod! Just uploaded pics and comment.

Should be nice to have for AM8

Does this make the y axis quieter at all? i have noticed the steppers themselves are silent but once they are up against the frame they vibrate and become really loud.

The rework is not supposed to make anything quieter. Mine didn’t

Hi, this upgrade it's compatible with Anet A8 2017 version?? Thank you

I don’t have the 2017 version so I wouldn’t know

Installed and i confirm compatibility!!!

I printed this a couple of days ago. 6mm threaded rod is not so easily found in hardware stores in the states. Instead of using 6mm threaded rod I used 1/4". I know: Heresy! LOL. The 1/4" rod is only 1/64" larger in diameter so a drill bit and a small diamond file took care of size differences. It's a great design and has made a huge improvement to my prints. Nice job, matsekberg.

Is there possibility to get original source file? I have problem with my version of Anet A8 frame and it will help me much. I can still try to work with STL but original CAD files will be much better. Thnx

I just tore apart my a8 for upgrades including these models and I can't thank you enough for creating and sharing them. The y tensioning is the best I've seen it's so solid. My only suggestions would be this:

  • People should not use the specific rod lengths you give. They should just put the parts in the printer and see for themselves where the rods should be cut. Mileage may vary from printer to printer. When I cut the rods to your measurements they were way too short. No biggie, I just got a new rod and just custom fit them.

  • Also I drilled a hole through the rear mount and plexi next to the stepper motor so I could add a bolt there through the frame. just helped secure and square it up a bit.

Otherwise PERFECT. Thanks again.

Hello matsekberg, in the STL you give the holes where the 6mm threaded rods go (motor side) are "opened" ( U shape instead of O )
on the pictures they are not
how do they fit then ?
thanks !

The u-shape was made to simplify assembly

Not OP here, but in the STL files it is U shaped.
I redesigned the whole thing for 8mm rods ( https://www.thingiverse.com/thing:2477814 ) and have them O shape, but the holes are deeper, so you can push them in one hole first and then retreat into the other and keep the distance with screws.

Y-axis rework for Anet A8 with 8mm screws

jack your stepper appears to be sitting at an angle. mine was like that too at first so I sanded a bit more on the back of the mount to make sure it was flat and added a small m3 bolt through the frame right behind the pulley. that keeps is from getting bent in and staying flat against the back

I think this is due to the fact, that I have a damper between my stepper and the printed part, to get rid of vibration and noise. Of course that would effect the accuracy negatively I guess :/

Can you provide the source files?
There's an update of the acrylic frame of the A6 so I guess that it won't fit.
Thanks in advance.

Tip: use locking nuts

Is there a version of this that works with the brace that goes between the brace between the back and middle brace?

Hello, I mounted the H with the bar down, so I have to use the file Y_belt_bedmount.stl and I mount the belt in this direction H - belt - Y_belt_bedmount?

Just printed in PETG and installed.. The next print over 16 hours runs about 90% fine.. then the nuts became loose and the belt slips. So I replaced the nuts with locking ones and everything is now fine. THANKS.

Yes locking nuts is a good idea

locking nuts or a second counter nut.

Is there any way you can separate the y axis belt so they two parts can be printed independently of each other please?

added a remix with those parts separated

yeah, please. I printer it over night and while printing the blue tape unglued and the smaller part became deformed. Now I need to re-print only smaller part.

ok, did it using Meshmixer.

Thanks for the tip. I was also able to use Meshmixer.


I'm just getting all the bits together for this conversion & printing the bits off.
I accidentally ordered a 20 Tooth Idle Pulley, Is this going to be OK to use as opposed to the 16 Tooth Recommended?

Thanks Rob.

If the 20 teeth pulley has a bigger diameter it might affect how the belt/carriage moves. But no firmware or config needs to change

That's great! thanks for the reply. I'll see how I go and report back. If it doesn't assemble OK with the 20T then i'll use the standard bearings and order some 16T


One of the best and my most recommended mods for the Anet A8.

I assume, that you have to upgrade firmware to Skynet3D - in order for the printer to know about the extension of the Y-axis ?
I assume, that the smooth (non-threaded) rods also are needed in longer versions ?

I use the same unthreaded rods. I do have skynet 3D both before and after Y rework. No recalibration needed for the rework (that I can remember)

How to offset Z in Cura 14 ?

Very good idea, but you should really advise to use self locking nuts.

I used nylock's when I did mine. I also jammed 2 together at the back end (by the motor). I could then grip that with pliers when adjusting the front tensioner.

So where do you get the extra rods for this build? Mine only has 2 rods right now. Please help, I'm definitely interested in checking this out

Buy in a store. Our local store has threaded rods from 4mm to 12mm for 2 euro's per meter. So I bought 1m rod M6 for 2 euro's and cut it to pieces.

so no one can help me and tell me why cura won't let me set the motor bracket .9 below the bed? and how to split up items that are in a file?

Try using Meshmixer.

How does the belt get held in place? Is there a picture somewhere?

The U-shaped thingy in picture 6 holds a belt pulley

I know that, but how is the ends weaved/held in by the two pieces? can u post a pictures?

Does this have to be printed in ABS? Will PLA melt under the heated bed?

is there a reason why there are slots in the motor mount where the threaded rods go?

So you can mount/remove the rods without loosening the front/back

has anyone found a way to add this mod to this frame? http://www.thingiverse.com/thing:2074599
I currently have it installed and it took a bunch of filament and I dont reall want to waste it

Anet A8 Y-Axis Idler & Motor Brace Upgrades
by Ecto1A
Anet A8 Frame Braces w/Y-Axis Belt Tension Rods

But then I have to reprint it ;( Waste of materials :(
Thank You tho

cura wont let me split the y axis belt2 any help ? also it won't let me set the motor mount .9mm below z any ideas would be awsome thanks

For Z axis, uncheck "Automatically drop models to the build plate".

Just installed this. Thanks Matsekberg. Rock solid at the front of the frame but I find some movement during prints on the back piece of the frame where the y axis motor attaches. That is the perspex piece flexes back and forth during prints. Any one seen any rear frame braces that will fit around this to stop the flexing?


Could you possibly either make the original files available so that I can change, or quickly open up the holes to 8mm..? I'm using what I have to hand, and have M8 threaded bar but no M6.

So what is the purpose of this? Also what advantages are there by doing this?

Its all in the description

Very great design, thanks a lot for this one!

Unfortunately the pulley holder is too flat for 18mm/12mm pulleys. Could you provide one that is 2mm lower?


"Bill of materials
1 pc. 6 mm stainless steel threaded rod, 340 mm long.
1 pc. 6 mm stainess steel threaded rod, 290 mm long.
Cut the 6mm threaded bars into two pieces of 345 and 295 mm length"

Please change to 340mm and 290mm (or delete, as they have that length in the bill of materials). Otherwise it's a bit confusing.

you updated the wrong dimensions i think. i cut my threaded rod to 340 and 290 and it is too short. also, the y endstop doesnt work now.. no idea why though...

Will this work with a Anet A6?

Yes just fitted it to mine.

Great thanks.

I have no idea.

@matsekberg Would you mind making the original CAD files available? I'd like to do another version of this to suit my needs.


What's your opinion on clearing that bulge on the motor side rod mount? If it was flat instead of being a nudge off It would be the best surface to lay on the bed.

I printed a new part with the bulge below Z=0 by setting it lower by 0.9mm and it came out far better than the first one. I'll post the pictures when everything is mounted.

Sure, I could do that so there is a choice to print it in one of two ways. I guess you could place it with the motor side down with the existing stl file. If you lower it a bit so the bulge is beneath z=0 when slicing.

Printed yesterday and installed today. Using 295mm and 345mm threaded rod gives no room for adjustment and can cause the rear frame piece to bow out a bit if you have a less than square frame from ANET. I cut 5mm off each for 290mm and 340mm and left a small amount of play for adjustment. Testing later this evening.

The 290 was a bit short, it worked, but I ended up cutting one at 292mm. 340mm worked for the right side, and left plenty of room for placement and adjustment. If you own an A8, do yourself a favor and BUILD THIS! Seriously, the best thing Ive done for mine yet! High five to the dude that designed it and thank you!

Great, I will update after your findings.

However, after reading all the different values people have mentioned, I just mounted the fixed end and marked the cut-off point on the other end with some tape. After cutting it and measuring, my rods were exactly 295mm and 345mm. So, it's probably best to not cut the threaded rod until you've mounted the printed pieces and measured from the bottom of the cup (aka the face) of the front piece to the bottom of the cups in the rear pieces. I guess as long as it bottoms out in the back and doesn't slip out of the front you'll be fine. :)

printed this yesterday and you do need 295mm and 345mm m6 threaded rod. very easy to install

285mm and 335 mm were incorrect measurements for me. They needed to be 10mm longer each to even get into the hole of the front brace piece

Same for me. Otherwise the solution is great :-)

Will I need a new belt for this rework or can the old one be reused? Sorry if this question has been answered - I scanned through the comments the but didn't see anything.

I think the old will be fine. But many recommends a fibreglass reinforced one, maybe change that too at the same time?

Thanks. I think this makes much more sense than the stock setup....

I have an ANET A8 with a TronXY aftermarket melamine frame so the front middle and rear lower brackets are much taller than original A8. Can you share CAD files so I can remix these to support my custom frame setup? I think everything is the same just needs to be taller so the bottom plates reach the bottom of the frame brackets.

I started to print the kit from file Y-axis_belt2.1.stl
I found that it is not simmetrical. Four pins are not in the center of the piece but 3mm holes are centered. So when I fit four pins into frame square holes then 3mm holes are misaligned. Same thing with cilinders for threded rods - they are not centered.
I read thet you " remade the two endpoints by moving the screws a little bit to the left" but I did not understand what do you mean. Anyway, i believe something wrong here - 3mm holes should be aligned with 4 square pins. Or I missing something?

I have exactly the same problem as this. On my frame the pins and the holes are in line, so when I fit this part the holes do not line up at all. It seems we do not all have the same front panel.

We all have the same frontpanel, but the four pinholes in our frontpanels are not centered (106mm and 104mm distance from the sides)
Try rotating your frontpanel 180° and it should fit.

Oups that's bad. You could cut the pins and screw the mount to a base plate. And of course screw the rest of the printer to the base.

All ok. I ended up just drilling out the holes a bit. It's only a matter of one mm so no big problem. Otherwise it's great and has come together very well. Thanks for this great mod. I'll post some pics when I'm all done. Cheers.

Yes, I really like this design and was going to install it on my A8 when I noticed that the acrylic parts were starting to crack on many parts (where the screw attachments are). I ordered the Anet/Tronxy melamine frame as a replacement. Upon receipt I saw that your braces would not fit the new front and back braces. I was wondering if I sent you the measurements if you would be able to convert your design to the new dimensions? I'm 70 and just received this as a birthday present in December and am working on learning CAD but don't have the skills necessary to do the needed work myself.

Randy Black

it's possible to use on tronxy?

I have a new version of this thing coming up.
First change is to move the rods 1mm to the left, seems like they where not exactly aligned with the heatbed.
Second change is to shorten the cylinders in which the rods are put. It was hard to assemble the thing in the printer. Also made slots in the two rear cylinders so you don't have to stick the rods in the cylinder, you can "swing" it in.
Coming up tonite.

I am looking forward to the new version, as I've not assembled the current :-)

Oups, forgot to upload :(

Hi matsekberg,

I'm confused:
did you uploaded the new files already?

Thx in advance

Now version 2.1 are uploaded, sorry about the delay.

No problem. Take your time.

Hi, does this also work for the Anet A6?

I'm thinking of remixing & integrating this into the frame brace itself, as well as combining an existing belt tensioner. It will all be in a single front piece. This shouldn't be viewed as a replacement for frame braces, but rather as an addition to them. There's no reason not to have as rigid & stable platform as possible. Besides, frame braces also provide a platform for mounting the printer to a base.
Good work.

Cool. My approach is to fasten stuff in my rigid wooden base and to replace wobbly designs.

I've reworked everything, & performed a virtual mock-up. It works. Take a look at what I came up with. I kept your basic model as well as my braced one. I just had to widen it for the most part, but it's still within the cut-out of the cross beam so it won't hit the frame

Anet A8 Frame Braces w/Y-Axis Belt Tension Rods

Hey i really like your design and its a lot less printing time then the other frame braces :)
but is there a possibility to make a version for 8mm rods? since i got some laying around, it would be so nice :)

That will require more redesign than expected. The space between the rods will be less or an even bigger redesign will have to be done. The code is a bit hardcoded so I think its much easier to get the 6mm rod and also get a sleeker design.

Great design and really want to incorporate this but my local supplier only has 8mm rod - any chance you could do the 8mm version? It would be so much appreciated - pretty please? ;-)

Could you share some pictures of how the belt gets fixed to the hotbed? I've printed the parts and purchased the rods. But I don't have a clue on how to fix the belt simply to the bed :-(

I plan to make a mount of some sort. But currently I just made a small metal plate with two holes and clamped the belt to the tray

You mean
belt belt
metal plate

I clamp the belt between the bed metal plate and another metal plate I made

I have added files for the clamp in a second.

Best THING ever for Anet A8.... like HESINE_M505...... WORLD DIFFERENCE as with a Giant frame add

Metal parts arrive tomorrow from Grainger, belts and gears came from Amazon today, two of the three parts are printed. I will have this done and installed this weekend. This has got to be the best upgrade. Thanks so much for it.

In the middle of installing this. Had to do some work with the holes and the belt tightener that I printed will not do the job it is to big. Going back to the original Anet A8 belt holder. I read an article, not sure here or over on the Anet A8 Facebook site, I believe that the stock cross beam for the bed support was installed upside down. It seems to look better when the bracket is mounted on the underside of the rail supports. Going to play with this. Thanks again, been a really interesting project. I think I spent $10 on the whole thing.

More to come.


I like the idea a lot. I use the frame support at the moment and I had to use glue to ensure the motor didn't move when tensioning the belt. Your approach seems more realistic and shoud suppress some of the vibrations. (Perhaps you could had a second hole on the bottom of your two ends (two screws could add to solid base)

Hope to test it soon :)

This is a great idea! I like the look of the frame bracing but this could be a really nice way to keep the Y axis super stable. My only issue is that it seems like you lose some of the tension between the front and rear frames and potential vibrating/movement since it's only attached to the machine via the rear frame.

I have a weakness in that I like to over-engineer things but IMO this would be AWESOME if it were integrated into a "frame brace" type design. It doesn't have to be anywhere near as robust but it would help keep the belt an integral part of the frame to prevent vibrations/wiggling. I'm going to print it anyways as I'm probably worried for nothing but it's a potential remix as I gain skills in modeling.


Y vibrations is not an issue for me, I bolt the rear motor mount to the one inch plywood/MDF base plate. The two threaded Y rods are also bolted down to the base so no vibrations there for me.
The only thing I worry about now are the Z "towers" not swinging left/right or back/forward.

Looks pretty good. I've got tiny artifacts on the boat test from the Y-axis movement, so this would be a good fix. Why they only use 1 screw on the one side on the original motor mount is perplexing. Mines twisted slightly from day 1. This design will surely fix that :-)

I still like the look of having a the frame supports.

Remix into the http://www.thingiverse.com/thing:1430727 ???

Frame brace for Anet A8
by Simhopp

With the Y rework there is no need for a frame support, not for the Y at least. The upward frame of the A8 may need some support not to wiggle front/back or right/left. But my prints with the Y rework are really smooth.

I needed this so bad. Thanks I will try this upgrade

Cool, let me know the results.

How has this been working for you? The principle seems good in theory. If you get promising results I will definitely give it a shot.

I have tested the first iteration with good results. Some minor modifications is needed, mainly to adjust space around the module. I have also added a screw mount on the front part to be able to fasten it to a base plate to kill all bogus Y-movement.
I had problems with a hotend mount breaking and Z-axis wobble due to not parallell bar and threaded bar, need to print a new X motor mount.

The best rework for an Anet8 is to start with a sledge hammer (for the fun because a kid's hammer would suffice to break it !)

now i understand. i like this idea!

...Z-axis belt tension ....

the z axis has no belt Tension?!

It's for the Y axis not the Z..

i KNOW! but he wrote Z AXIS! than hhe changed it after i claimed this! read the comments!!!!!

Oops, typo fixed. Thanx.

I know it’s been said but:

This is a totally awesome mod to the A8. The design is very good and the execution perfect. I absolutely love it.

I never understood the problems others posted about because it all worked perfect on my machine - although I did have to make a custom belt clamp to give more forward clearance. But only because of the Bowden tube conversion I made (which I also love).

Thanks Matsekberg!!

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