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Anti Z Wobble for Anet A8

by saschai Oct 29, 2016
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this is not an 2mm pitch A8 lead screw. that looks like the frame screw. did you put this together wrong?

Comments deleted.

I personally wouldn't do this as it decreases your vertical print height by about 2 cm.

This is a really bad idea. If you want your A8 to work properly don't make parts like these.

This is not only unnecessary on a properly set up machine, but is really a bad idea from an engineering point of view. The reason the leadscrew is free to float is to avoid potential binding due to the convergence of the two axes. This binding will cause far more problems than the wobble (run out). The run out will not affect printing performance. I have two of these printers set up in different configurations and have designed and used many of the modifications available. The mods addressing electrical safety are critical. As shipped, this printer would never get CSA or UL approval. Replace the power cord, install a fused switch and cover exposed a/c contacts. Frame stiffening is a good idea as is a Bowden mod to reduce print head mass.

glad I read this before printing. thanks a bunch!

Wish there was a way to upvote comments.

A8 owners: Your threaded rods should swing about freely in the hole. Adjust your coupling. Do not use these "fixes". If your threaded Z rod is even slightly bent, this will actually make your prints much worse.

Andyman257 is correct, this part is an anti-pattern that has been plaguing the Mendel derived designs for years and years.

Because it's sinking to the bottom of the comments - please find and read the post by 1BigE. This part is not required if your threaded bar is set up correctly. There's a PDF posted that shows you correct fixing.

i would like to know where you purchased these upgraded screws from . Thank you

what screws do i use

None, because this is a bad idea in the first place. There is literally a way to adjust the z motor couplings. I would HIGHLY advise against this, as it WILL mess up your printer eventually!


Der Anti Z Wobling passt Perfect. Abstand Trapezspindel zu Laufschiene ist 100%.
Kugellager 8x16 rein machen und Glücklich sein. Leider sind meine Trapezspindel zu krum, das ich mir
diese wieder abbauen musste. Jetzt mit neuer Präzision Spindel und Präzision Laufschiene ist der Anet ein Traum !!!

8x16 ist falsch. Es werden 8x22 Lager benötigt.
Ich hab leider erst die Lager wegen dieses Kommentars gekauft und nachdem Druck festgestellt das es nicht passt.

Sorry, but doesn't fit, too large piece, wobble still there
Trying to design mine
Thanks for experimenting


1) Can I use a spinner bearings?
Most of the generic plastic spinners are 608zz for the 3 bearings at the edges and 608 for the main middle spin bearing.

2) Does the bearing need to spin alot?
The spinner bearings I have do spin but not freely.

they work (i took them from my sister) and they only need to be able to spin a little

if you take the rubber rings off the bearings it can spin a lot faster, however it is more prone to getting clogged.

Well they don't spin freely. It's more like it moves when you turn it.
But I guess this wouldn't matter as the rod spins using the motor and the motion isn't fast.

Using spinner bearings does save me money:-).

Hello saschai,
thank you for designing. In relation with correct adjusted t-shafts (it took me some time) this thing helped me to decrease tha last z-wobble swings. I tried also a variant of your other anti-z-wobbler to decouple the t-shafts from the guide-shafts but it made the wobble worser.
It's really important first trying to install t-shafts correctly.

Can't thank the creator enough for this design! It completely eliminated all of the shaking and squeaking my printer made while moving up or down on the z-axis. On another note, I honestly just use these and not the other anti-z de-wobblers that suschai makes. I have had too much trouble trying to get those to work. Also, I printed the 608ZZ bearings from another creator, and after a little smoothing and widening of the bore, they work perfectly! Very well done

Hi saschai, did you do this Anti Z Wobble for Anet a8 on Autodesk Inventor? If yes can I PLEASE get the file to make some changes to it. Like: make the bearing fit in without wobbling inside of it.

That was a long time ago!
Nothing left.
Did in 3d max

the bearings (608ZZ) don't fit the rods. oO

This piece slides on the flat bar, impossible to fix the piece. Even by tightening the screws the anti-z continues to slide sideways.

This articular element! It should not be fixed firmly! He must have freedom to work!


So two things:

  1. The bearings (608ZZ) don't fit my rods. I went into the comment section of this thing and what I found led me to number 2.

  2. The reason the rods don't go all the way up is because you have to adjust the connectors that connect the rod to the Z motor higher than you would think. You actually have to pull up on them while the motor set screws are loose (not the top Allen set screws, the bottom ones that hold the coupler to the motor shaft). You then lift the coupler (and connected rod) up until it sits flush with the top of the acrylic holes.

So, I guess now I will go make some spinners with my new bearings that I don't need.

Thanks for trying to help though!

Does this make any difference to your print I mane connecting the rod to acrylic frame

I can't slice it with simplify, there are spaces between different surfaces and some reaming hollow. I tried repairing it with meshmixer but with not good results. Can you check that? Thanks.

Colleagues in the last time !!!
1 screws fastened correctly, screws really short!
2 Flexible couplings I used

  • standard
  • A flexible rubber insert
  • Printed
    3 My device does not fix the screw tightly in the upper part of the frame (there are two degrees of freedom)
    4 The most important thing !!! The device works together with http://www.thingiverse.com/thing:1858459 I wrote in the description of my device. In this case, the screw has no connection with the carriage axis X and a single point of support flexible coupling.
    5 I will not impose this device, I just shared what helped me to print higher quality parts.
    6 I do not want anything to anyone to prove!
    7 I put pictures for comparison, let every man for himself decides for himself!
    8 I've got rid of my Anet8 and to be honest not much regret it !!!
    9 I turned the page and do not want to return as her!
    Sorry for my english
Anti Z Wobble for Anet A8
by saschai

Before you try any parts like this, please not the hole in the top frame support above the Z axis lead screws! If you believe your screws are too short its possible that the motor couplings are installed too far on the stepper motor shaft, if you loosen the set screws on the stepper shaft side of the coupler then slide the coupler and lead screws up until the rods are inside the top frame at least 1/8" you should be good, tighten the set screws back down on the stepper motor shaft. As others have mentioned, leave the lead screws to wobble some, this will allow the carriage to travel freely along the plane.

1BigE is correct. This part is useless. DO NOT USE THIS PART: Read Below.

Al the people who see who are printing and using this have it all wrong. It will "work" for some people only because their lead screw is off center. It happened to me, one rod was a little off and was causing friction going up and down. If I actually pushed it slightly, it would be perfectly straight.

So if this works for you, that just means your lead screw is misaligned, crooked, or bent, and this part is just pushing it back straight.

You should not need to use and you should not use this part. The lead screw is MEANT to be free on one side. Hell, look at the couplers on the motors. Notice the spiral cuts in it? Tug on the screw. Notice how it bends at the spiral cuts? That's because it was designed to be free at one end. The screws are not what is keeping alignment. Your printers body, and the smooth, fixed rod next to the lead screw is what keeps everything aligned. The screw is just what allows for Z motion. Adjust the couplers, adjust your printers frame, and test.

While this part will remedy a misaligned frame or fixed rod, it is temporary, and doesn't fix the problem. Even though your prints may be better, they absolutely will not be as good as they should be, because the lead screw is not meant to be fixed at two points.

I didn't read the comments before printing and installing this part. After the modification I noticed that the quality of my prints had degraded. And then I realised that if a screw rod is at least slightly misaligned and it is fixed at three points it will push and pull one of the points.
Eks_Whyzee and 1BigE are correct. This part shouldn't be used thoughtlessly.

I think your right. I just set up my A8, and noticed the two Z screws were not touching anything at the top, and just wiggling around in space. I realize now that I simply dropped them into the couplers, letting them drop to the bottom. If I raise them up that inch or so, hopefully the screws will reach the holes that are in the top of the frame. I will try that solution first. If need be these bearings can be purchased at gearbest for less than a dollar

Comments deleted.

Sorry, saschai, but this isn't an "upgrade". The Acme threaded rod is not meant to be solid like that. It should float freely at the top. This is just going to lead to binding on tall prints.

I do see that your Z coupler is not adjusted properly, and this is why you are getting z wobble. Adjust the coupler so that the acme thread is level with the top of the printer. Boom. No more need for this.

Thanks for this. Came looking for a solution to print, and found the correct solution in the comments. Adjustments made!

Do you have pictures you could show to explain what you meant? My threaded rods are short as well, but that appears to be the way it was designed and shown in the installation instructions. The rods are at least 1cm too short to reach the top of the printer.

Thats normal at the A8 ..

I can't post pictures here, but here's a link to a PDF showing the proper installation


Thank you mine were all the way down and rods were clear of the top by 5mm had some caps on them. Looks like a big improvement now I have installed them as shown.

<- Happy camper :-D

How did you know this is the "proper installation" I just noticed that threaded rods were not perpendicular to the ones next to them so I was going to put this on to "fix" that problem, but after reading its only because I don't have the proper setup?

With adjustable everything is fine!
I originally tried various couplings, including printed out.
Screws are actually short (344mm and 346mm)
I already wrote:

  1. The device has no rigid fixing
  2. He works together with the other device (see below)
    I bought a new screws (qualitative and normal length :)).
    Print quality became better than with the old screws, but worse than a modification times. Perhaps, purely subjective (see. Photo)


You are missing the point. The screws aren't too short. You have them set up wrong. There should be a big gap between the top of the z motor shaft and the bottom of the screw. If the gap is big enough, then the screws will be level with the top of the printer.

If you have it set up properly, you don't need this, and it prints better without this. Of course, if you insist on setting it up improperly, then this Band-Aid fix might improve the quality.

Friend, I use the 3D printer from 2012 (model i2).
Believe me, I know how to properly install couplings :).
I probably bad writing in English.
Once again, I write:
My screws shorter than standard.
If they are even completely pull out of the couplings, they reach the upper edge of the panel

The device works together with the other device (see link).
When a single point of support - flexible coupling(And all).
And screw can swing in a very large range.

This device concept is not new.
I have it running on the old printer.
I added a photo.

Well, you can lead a horse to water, as they say. Your couplings are definitely not installed properly. Just because you've been doing it wrong for four years doesn't make it right.

Odds are I've been doing CNC since before you were born.

LOL. I'm done here. Obviously I'm not going to change your mind. I was just trying to help others who might be steered in the wrong direction by this project.

1BigE, many many thanx for clear description. I think more people needs good documentation. Share knowledge is really welcome. Again, many thanx

Thank you 1BigE. Not everyone is learning resistant and you just tought me an important lesson, thanks :)

Friend, I'm sorry, I did not know that you have so many years, I think not less than eighty, judging by your comment. Well, then it certainly will not even arguing, you're right about everything :)))!
P.S. Please note, I'm nobody, nothing, do not impose!

An example from the official installation video: https://i.ytimg.com/vi/zi1wV4qAyIA/maxresdefault.jpg
I guess you are right with your setup.

if it doesn't fit ill modify it to fit.. props to ya with bearing amazing absolutely the best concept and small print time design A++ keep up the good uploads

Awesome, let me know when you resize it :)

This does not fit my A8, it is too wide.

Friend! I do not know how I can help!
I took the size and printed to a real printer. This printer works for me already almost a year.
Perhaps the manufacturer has changed the dimensions.
Perhaps the problem with the configuration.

Comments deleted.

Listen even I do not want to argue !!!
Complete with http://www.thingiverse.com/thing:1858459.
Screw rests only on the flexible coupling. Other points of support no.
Where to leans screw on the flexible coupling, one devil known
My device has two degrees of freedom. No rigid fixation!
It is close to the self-aligning bearing

Anti Z Wobble for Anet A8
by saschai

I printed your Anti Z Wobbler Part, unfortunatly the 608ZZ Bearing seats not tight. Do you have any suggestion what I can do, except taping it for a tight fit?

Heavy landing bearing is not needed ..
If it is very bad, use a drop of glue (PLA) or drop plastic dissolved in acetone (ABS)
No need to use super glue or glue with strong fixation

Hi, I want to attach this to my anet a8. Can anyone tell me how, or why to use in conjuction to the other "Anti Z Wobble" Part?

Remove the hard connection to the X-axis (lower unit set)
If you do not set an upper bearing, possible strong fluctuations of the screw.
At least it was for me.
No rigid connection to the X axis of the holder.
And on the flexible coupling may sausage strongly