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

by LittleMrJ Feb 17, 2017
Download All Files

Thing Apps Enabled

Please Login to Comment

Thanks a lot. Front and back of my frame cracked from too much y-axis tension (possibly due to small fingers playing with the tensioning knob I'd added when I wasn't looking). This fixed my problem (I was able to print it despite the cracked frame, which I superglued and clamped to hold together.

A good, all round brace that i printed over two years ago. Looking back at it now it would be great to make some room for a stepper motor damper on the rear brase. All you need is 5-7mm and you would have the space (3.5mm off each side). Dampers help to cut out a lot of the sound.

Did you notice an improvement of the quality of your prints? Not surprisingly I have problems with vibrations on mine and using dampers helps but they are still there.

Thanks for the design, really helped give my “wood” CTC A8 some rigidity.

Just printed and installed. It fit like a glove. Back brace could use some tweaks to support threaded rod boss and some adjustments to give allowances for a screw driver when installing the Y-Stepper Motor.

Current front brace needs support material for bosses.
Current Rear brace needs support material for bosses and some overhangs and wiring holes

I printed in PETG, which is stronger than PLA to provide better rigidity.

This has been one of the best "upgrade" prints I have done to my A8. I have been using it now for a couple months and it is amazing. Big thanks to LittleMrJ!!

I use a silicone damper with the original y-rework. It is a simple 3mm Nema17 damper. No Problem, there is enough free space...
I printed the front brace, it works perfectly....now I want to print your rear brace, but that would mean that I have to remove the damper.

Would it be possible that you do a little mod for the Nema17 Damper? ( I still have to learn CAD)

Like moving the part of the brace left to the stepper motor 4mm to the left? I would screw a 3mm damper between stepper motor and brace (to the right) and put 1mm silicone damper between brace and motor on the left.

Thank you a lot for this ultimate frame brace design ;)

I'm going to try to remix this to add the stepper motor brace as seen in ykimhi's remix (https://www.thingiverse.com/thing:2350830) of matsekberg's original.

Frame brace with y axis motor mount for Anet A8
by ykimhi

the front brace does not fit .
Bad design and waste of time and filament

I agree with Iomax1987. The back brace is too high and hits the y carriage bearing blocks. The front brace is just a frankensteined monstrosity of 2 items that are not aligned properly, and do not fit the front of the printer.

Pretty much a time waster, had to modify everything after printed.

I don't know what to tell you. This fits & works perfectly for me, with photos showing as much. Anet isn't the bastion of precision, they can make asymmetric parts.

I'll just remove the damned front tabs, that seems to be an issue with some people. It really doesn't need them anyway.

As far as the bearing blocks, if you are still using the bulky stock aluminum bearing blocks, upgrade them to a slimmer design. However, this worked for me before I upgraded to better blocks too.

I removed the front tabs with a dremel afterwards, but that still gives the issue that the m3 holes do not line up as such the M8 rods do not fit when they are placed. maybe make the holes for m3 sliding holes.

the 2 M6 rods are not 100% centered at the front, thats an issue with tinkercad snap grid I think happened?. maybe ungroup the 2 items and set snap grid off, and/or place both the front and back part on top of each other to see. I didnt see any issues in prints btw when using it.

The bearing blocks I use are the original ones, cause this is my backup printer. but isnt the whole idea of this, to make the original printer more rigid? buying other blocks is a bit against that idea in my opinion. A simple 2 mm (or even make it follow the original arcylic?) lowering of these bariers, fixes that. I fixed with dremeling the thing.

Maybe I was a bit salty and im sorry for that, but it costed allot of material to print, when I was hoping I wouldn't need allot of time with my backup printer to get working again.

Thanks for taking the time to check the issues out

The entire purpose of a front frame brace is to reinforce the acrylic frame panel, as belt tension will, over time, slowly bend the acrylic. My little system here removes belt tension from the front frame entirely. The front acrylic frame piece isn't actually needed now, other than for a shiny accessory. The back brace stiffens everything else up a bit, and makes the system functional. It was an experiment, a mashup of 3 other designs. I'm satisfied with it, as my frame is very ridged, & mounted to a base. Sorry some people have issue with it, I realize how long this takes & how much filament it uses.
I wasn't suggesting buying different bearing blocks. I designed my own: https://www.thingiverse.com/thing:2274088
As far as the M3 holes, I should just remove them too, so everyone can drill their own holes to line up to their specific frames.

Low Profile Bed Carriage Bearing Box

Did fit on my printer. Have you tried to turn the front brace by 180 degrees? It wasn't symmetrical on my printer. Turned it around and the brace fits.

Can you please post here some kind of editable file? I'd like to make 8mm rod version :)

All three of these files ARE editable. What CAD program are you using which won't accept .stl files? It takes all but 3 minutes to load them into TinkerCad and make 8mm holes.
Or, print them out as is, then use a drill bit to ream them.
Or take an 8mm rod, heat the end, & melt a larger hole.
I've done the hard part, & offered it to the world. It's up to others to modify or remix it.
Figure it out, I did.

I would prefer a 8mm threaded rod version. I have a 6mm rod already and it seems very flexible. Is that really enough to strenghten the frame?

The braces are reenforcing the frame, not the rods. The only thing the center rods are doing is relieving belt tension off the front frame panel. 6mm should work fine. After all, you don't need to tighten your belt very much anyway, it's not a guitar string.

Can you please update the length of the rods? 34 and 40 are clearly not correct. Shorter one should be around 30cm and the longer one should be around 34?
I just started to print and did some measuring, so i can not post the correct values yet.

Yea, I have no idea where I came up with those first numbers. One is 30.5cm & one is 34.5cm. 30 & 34 will work too.

What kind of belt holder do you use for this?
I find many thst are to big and doesnt fit between the threaded rods.

Comments deleted.

Any chance you can make this work with 8mm threaded rod? it's MUCH easier to get in the US. I have 6 feet of it already.

Yes I CAN make this work with 8mm threaded rod. Take a 5/16th drill bit & ream the holes larger.

i have print the files,
but the M6 longer are bad,
someone can give me the longer for the short side end the longer side please (34 & 40 are not good)
i have a anet a8

Yea, my first description was bad for some reason (I drink a lot). 30.5cm & 34.5cm are good. 30 & 34 work as well.

Can anyone other than LittleMrJ (no offense) confirm, that this fits now?

is the infill mandatory to be 95% and above? or can I get away with 20% or 40%?
thank you

God no. I think I only used 35% infill.
The .stl file doesn't have a preset infill, that's just your slicer setting.
It would take forever to print at 95%, plus it would use all your filament. Don't do it.
Change that shit.

I've purchase a Tronxy 802/Anet A8 replacement melamine frame. It is cut from 1/4" stock. I have the dimensions of the front and back frames in inches/fractions. I am still learning CAD and at 70 things sometimes come slowly as I learned drafting old school and have difficulty making the change. Would you be willing to redo the brackets (small items) for me? Just tell me how to send the information to you.


At least on my printer, the front brace doesn't fit as designed. This might be an issue with my printer though, as the holes in the front plate are not symmetrical - when looking from the front, the four holes for the tenons start 10.4cm from the left side, but 10.6 cm from the right side, with similar measurements for the 8mm holes for the outer threaded rods. The model is designed symmetrical with the correct measurements for the right side, which leads to the left hole being 2mm too far left when printed.

Also, the small bar at the very front that goes below the acrylic frame is too thick. There is 4.8mm space between the lower tenons and the bar in the model, but the actual piece requires at least 5.6mm. I've since filed that down quite a bit and now it fits.

I'll add more details, pictures and measurements tomorrow, but before you print this piece, you should make extra sure it fits on your printer.

I tried installing the back brace but unfortunately, I ran into multiple problems, making the parts unusuable for me. I've detailed them with photos in the "I made it" section. Again, if you plan to print this, double check it will work for your printer.

First let me thank you for jumping into the water and analyzing this one. You're the first, awesome.
Second, I'm sorry for your result. Your photos looked bad. I got mad at myself & tried to see what happened.

I printed out the front piece, & it fits perfect for me. Very flush & smooth. I checked the back piece again, with the mock-up model of my own frame. I do notice the error with the rear frame being 2mm off, but cutting or melting the tab away should save from reprinting another piece. The bolts & nuts should still have space to hold it firmly in place.
As long as you're experimenting, try that. I'd hate to think it was a waste of time & material. You may be able to salvage the idea, & maybe see something new. Cut that tab off, center it correctly, & see if the bolt holes line up well enough.
Thanks again.

Wait, don't bother cutting anything. I SEE IT NOW. Cutting off the tab would shift the rods. It will either be off-center, or the motor won't fit. It's the motor mount bracket & tab which is off by 2mm, the rest of the piece is centered. One small error is throwing off everything else in the brace.

*Edit: I fixed the 2mm rear tab offset, everything else looks good & centered in CAD now.
As far as your front bracket, that just looks like a bad print. I'll post pics of mine. Our holes may be off as well, I've seen a few weird asymmetrical Anet errors on Thingiverse.
Thank again for helping. If you need me to throw time into something you have, I'm down!

Hi. Thanks for the feedback.

As I said, in case of the front brace it appears to be an issue with the acrylic part of my printer - it should be symmetric but it's not, but that was easily fixed with a bit of sanding and drilling. The printed part had the same dimensions it should have according to Blenders protractor tool.

I'll try to print the back brace again, but unfortunately, this will take a bit of time as I will be traveling in the next three weeks or so. When I get around to it, I'll get back to you.

And BTW, thanks for taking the time to design that piece!

Cool. Just know to download the very latest versions of whatever you want to print, because people constantly update their designs, including me. If you print something tomorrow that you downloaded today, it may already have become a different design. Most of us in here are constantly experimenting with everything.

Relly like your design I wanna start with the front brace is it all good to go everything should line up ?

Yes, I've printed, tested, & tweaked everything. It's on my printer now, & fit's like a glove. I've also added pics. I may tweak the tension arm in the future, to allow for a larger toothed idler pulley, but that's not a big deal to reprint.

There were a few re-works as I tested the system. Everything is aligned & fits my Anet perfectly. Keep in mind, Anet isn't the bastion of perfection either, you may have a frame with off-center holes, or other errors, as another user pointed out.
Many tweeks have been added, so download & print the latest version, don't print anything you downloaded from here days or weeks ago.

so you made it even worse with the latest changes to the backbrace.
There now is no way to get the stepper in there. Also you didn´t add a hole to get the 4th screw to attach the stepper fully with all 4 screws.
Pls for the future, testprint your things before you publish them..especially big prints like this.. Do not use CAD to look out for mistakes or misfits cause you will most certainly miss something else important.
Messure the distances between the rods and the frame and also between the rods themself to center the M6 rods properly.
I am kind of pi..ed because i printed your first version with it not fitting several weeks ago and now the second one thinking you solved the issues with it being clearly shown by svenwhd and his "made" pictures. This took almost 15h for both printing not mentioning the material thrown into the trash.
Can you upload the step files so i can mod them myself, that would be great.

No offence, just criticism ;)

Thanks, no bad criticism here. I have printed & installed this system on my printer. It has been fully tested & altered with improvements. It fits my Anet like a glove, & functions as intended. The rear stepper fits perfectly, & access windows have been added for screw access & wire routing.

Hi LittleMrJ,

This is a great design!

I read in the description that there are issues with front panels that have off-centered holes. Then I read the comments. But I didn't fully understand the answer you gave to svenwhd about this. Did he (or you) finally came out with a solution?

Btw, I doubt this is a failure from Anet since it seems to be very common with the printers manufactured in 2017.

Thanks for your reply.

Comments deleted.

Printed the rear brace and about to print the front.

hows it going with everything aligning up ?

The back worked fine for me but the front took a dremel to persuade it in. But I've been running it since then without issues. Not sure what changes the creator has done since I printed mine to correct the problems though.

Would you recommend printing it? Even with this issue?

Does it make a big difference in the printer?

Another negative point is that there are cheaper and faster options. You do have to go out and get a metal rod, cut it, and get a few extra nuts and washers. Only a couple bucks but...

I can't say if made anything better or that it is better than the other frame braces out there. I would probably print it again if I had another printer. I like how easy it is to tighten the belt and I think it makes the printer look better (only my opinion)

I have been meaning to remix the idler arm to allow for more clearance for a metal idler pulley.

Also, the rear brace seems to conduct motor noise more than the stock setup did. The version i printed allows enough clearance for a dampener to be installed, i just have not taken the time to do it.

Sorry it's not a definitive yes or no...

You're right about the added noise, but I think that's a good thing, it means the printer has more surface area contact with the base. It's much quieter once you mount it with screws, & Igus bearings eliminate a lot of noise too. I think mine is much quieter now than my first print was.
I see what you said about using a Dremel, I used a soldering iron to melt it to fit. I've since fixed the issue in the design file.

Looks interesting. Is it compatible with a Nema 17 shock absorber?

Not currently. The hole pattern is the same, but the absorber pushes the stepper back into the brace. You'd need to shave off 15mm on the left side behind the stepper, as a stepper alone is currently flush against the brace.
Not a big deal, I can fix it for you in 3-5 minutes if you don't know CAD.


Thank you for this fantastic design, I'm printing it as we speak. I'd be interested in a slimmer rear motor mount, I replaced the original one, which is 38mm in height for 40mm, it barely fits on the stock frame without crashing with the bed. Will it be possible for you to make the motor wall slimmer?

I could try to do that but I'm not sure how with TinkerCad or Fusion360.


I think about doing a remix fitting for the shock absorbers and for a 500mm frame (as I update to a 200x300 heat bed).

Im also interested using this + nema dampers. Hope it will still be strong enough

I would really like a shock-absorber design, too. ;)