BLV mgn12 mod for Anet A8 / AM8

by Blv, published

BLV mgn12 mod for Anet A8 / AM8 by Blv Oct 21, 2017


BLV mgn12 mod for Anet A8 / AM8

  • The main purpose of this project is: converting your Anet A8 into an incredible 3d printer, using MGN12 rails fixed on an aluminium extrusion frame.

  • This upgrade compatible with pheneeny's AM8 mod with small changes. (Huge credit!)

  • Why mgn?
    The linear bearing and Delrin Wheel Gantry commonly used at most of low-mid 3d printers as a cheaper solution for linear motion. Its cheaper replacement for the expensive mgn rails BUT price is at the expense of accuracy and reliability. Well, linear guided rails (mgn rails) are much more rigid, extreme precise and smooth then linear bearing or Delrin. The linear rails lets you print with higher speed - shorting print time without compromising print quality. The fact rails are fixed to frame prevents unwanted motion related to bent threaded rods or other axis's motion. There seems to be a good reason why they are mostly used with high end 3d printers..
    So, i found cheap chinese mgn rails at Aliexpress and thought to myself why not?


fixing the mgn rails can be very frustrating. it need to be perfectly aligned and straight.
else, it will give you a headache, so don't start this project without tons of patience.

  • Please notice:
    Unfortunately, few days after started building this model, I was injured at work.
    So, right now i am recovering from cornea erosion - long story..
    Basically, I meant publish all the files only after putting all together but a lot of community members was asking for STL files. Therefore, all the files needed to build it released here. I'll appreciate every thoughts or suggestion that you will share with me.
    Thank you guys :)

  • design flexibility and Source file
    I'm sharing with you the source file of this project in order to improve the design and make it even more better. you will find the STEP file inside the project zip.
    Please follow the item license (under the Creative Commons - Attribution - Non-Commercial - Share Alike.).

  • Also made for this project a Build plate for simplify3d

Please notice you may need to re-center bed coordinates via marlin configuration
or change Z extrusion position to center the hotbed

Build it at your own risk.

Latest video update
A quick peek at my project building progress.
sorry for all the exposed wires - i had to test it. first video after all axis's electronics had been connected. Next week i'll get the 400mm threaded rods and install the rest.
I had to reverse x-motor connector in this video beacuse mistakly i fixed the carriage screw on the back instead on the front (i fixed and uploaded the fixed x carriage).


  • 7/1/18 All STEP files updated including: Main Printer, Cube carriage and MK3 carriage.
  • 6/1/18 New experimental Cube carriage supports V6/Clone BLtouch, 8mm/12mm Sensor (required 4010 blower fan). (inspired by CR-10)
  • 6/1/18 New MK3 carriage made for Prusa original MK3 nuzzle fan support BLtouch, 8mm/12mm Sensor. I Love this Carriage !!
  • 6/1/18 New X-screw holder extended
  • 6/1/18 New holders made for 30A/29A 360W power supply.
  • 6/1/18 New X motor holder added a 4010 fan holder to cool the X motor on higher speeds.
  • 6/1/18 New 4010 Spitfire style fan cover for the New X motor holder.
  • 6/1/18 Modified the rear corners which allows threading cables through extrusions.
  • 8.12/17 improved bed adapters for better slicing process.
  • 25/11/17 added 2 type of Jigs that helps aligning the mgn12 rails
  • 17/11/17 added a new experimental carriage adapter for Anet A8 Original carriage
    STEP file updated ! (can be edited with any CAD software exp: fusion360)
    added X-motor cover+cable holder (infill 65%+)
  • 05/11 added X-Carriage for E3D Chimera Hotend
  • 02/11 new LED strip holder (compatible with regular 9.8mm strip width)
    new rubber feet mount instead of the tapped method. (Print with 60% infill)
    new improved X-Carriage (added on both sides cable holder)
  • 28/10 BOM updated
  • 27/10 added Heated bed Belt locker (belt_lock_infill80.stl) (infill 80%+)
  • 26/10 fixed x-carriage (the belt holder holes are now on front - reveres x motor not needed any more)
  • 23/10 BOM list updated (added solution for AM8 with 440mm z extrusion)
  • 22/10 added Cad Source file due to community request (BLV Mgn12 mod.step).
    added BOM file (pdf)
    added printing orientation images

Quick video: It's alive :) the first axis test..

Choose your Style

Mod variations:

You have the ability to choose your own style:

  1. Anet A8 converted to AM8 (original height: 440mm)+ BLV mgn12 mod:
    If you are already a proud owner of an AM8 printer and don't want to change the orignal height, you will have to get a 350mm rails instead of 400mm .

  2. Anet A8 converted to AM8 + Higher Z-axis (height: 500mm) + BLV mgn12 mod:
    First you will have to build an AM8 with a small changes:

    • instead of: 2x440mm 2040 extrusion > replace with: 2x500mm 2040 extrusion or bigger.
    • instead of: 2x340mm 2040 extrusion > replace with: 4x364mm 2040 extrusion
    • get a longer threaded rods 400mm.
      obviously, you don't need to print all AM8 parts but some (more info at printing info section)
  3. Anet AM8 + Free style + BLV mgn12 mod:
    As i mentioned, the design is flexible and includes separated parts that can be fitted to your wish. if you want custom size printer with a bigger bed or higher Z-axis, please choose wisely your own extrusion size and attached the modular parts to your desired extrusion.

Requirements & BOM


  1. Anet A8 printer > AM8
  2. Tools
  3. Technical ability
  4. spare time

BOM - parts you need

clarification: BOM includes AM8 BOM.

  • 7 x Mgn12H Carriage (4 for Y-axis, 1 for X-axis, 2 for Z axis)
  • 3 x 2040 extrusion 313mm (for top, front, back)
  • 4 x 2040 extrusion 364mm (Y-axis)
  • 1 x 2020 extrusion 420mm (x-axis)
  • 2 x 608zz bearing (optional: if you intend using the top threaded rod holders)
  • 16 x HBLFSNF5 Corner Bracket
  • 150 x M5X10 Button Head Socket Cap Screw
  • 8 x M5x10 Socket Head Cap Screw
  • 6 x M5x16 Socket Head Cap Screw
  • 4 x M3X20 Socket Head Cap Screw
  • 60 x M3X8 Socket Head Cap Screw
  • 1 x M4X30 hex head (y-tensioner button)
  • 6 x M3X20 screw
  • 1 x M3X32 screw
  • 20 x M4X10 screw
  • 160 x M5 T-nut or M5x.8 Square Nut
  • 40 x M3 T-nut
  • 4 x M3 nut
  • 13 x M3 Washer
  • 1 x M3 nylock
  • 20 x M4 nut
  • 20 x M4 washer
  • 6 x Rubber Feet
  • 2 x GT2 16T idler (3mm bore)
  • 1 x 5 meters GT2 reinforced fiberglass belt 6mm wide pitch 2mm
  • 1 x PC4-M6 OD4mm (optional: if using greg's geard extruder)

for option 1 (original AM8 size):

  • 2 x 2040 extrusion 440mm (z axis)
  • 3 x Mgn12 350mm rail (x & z axis)
  • 2 x Mgn12 400mm rail (y axis)

for option 2 (extended z height):

  • 4 x Mgn12 400mm rail
  • 1 x Mgn12 360mm or 350mm rail
  • 2 x 2040 extrusion 500mm (z axis)
  • 2 x Threaded Rods 400mm

Additional electronics BOM

  • 1 x e3d v6 hotend or Clone
  • 1 x e3d Chimera hot end

What & How to print

Part to print from this BLV mgn12 mod project:
print all except those optional parts:

  • Y mount motor - (print this part only if you dont have the AM8 Y motor mount)
  • Top z holders - (aka anti z-wobble) (holders may limit Z height and they are not really needed)
  • Caliper Holder - (print only if you have a digital metal caliper)
  • LCD case and brackets - (print it only if you have a reprap Discount LCD 12864 only, else use the original AM8 lcd case and brackets)

Part to print from AM8:

  • 1 x 1_LCD_Base_Left (only if you are planing to use the original Anet A8 lcd)
  • 1 x 1_LCD_Base_Right (only if you are planing to use the original Anet A8 lcd)
  • 1 x 1_LCD_Case_Top (only if you are planing to use the original Anet A8 lcd)
  • 1 x 1_PSU_Mount (for Original Anet PSU)
  • 1 x 1_Wire_Holder
  • 2 x 2_Bottom_Tee_Plate
  • 2 x 2_Top_Corner_Plate
  • 4 x 4_Bottom_Corner_Plate
  • 1 x Anet_Board_Mount__With_Fan (dont print if you choose the electronics box)
  • 1 x Anet_Board_Mount_No_Fan (dont print if you choose the electronics box)

Material and Infill

Inside zip file you will find a PDF file named: BLV mgn12 mod.pdf
which contain full spec of the Parts (name, material to print with and infill percentage).

Printing orientation

Highly important: i added 4 pictures showing printing orientation of the prats.
the printing orientation is very important because it contributes to the strength of the items.

  • make sure before printing that its calibrated since the dimension precision are crucial !

view original size: open it in a new windows and save the image or use the pdf file inside the zip files

view original size: open it in a new windows and save the image or use the pdf file inside the zip files

Assembly instructions

  1. Assemble the frame extrusion according to pheneeny's AM8 mod
    at the AM8 mod files you will find also the prefect guide pheneeny made for assemby.

  2. Assemble the BLV mgn12 mod according to assembly instructions that found in this project zip file. its a pdf file named:BLV mgn12 mod.pdf. the file contains sketch with all
    the main parts.

  3. I made an assembly video in order to explain how to assemble: Bed adapters, X-axis components, Cube carriage and V6 carriage.
    Please notice you may need re-center the hotend/bed coordinates via marlin configuration.

Additional Parts

Additional Optional Parts

MGN12 rails & Carriages extra info

MGN Rails

Well, i used a cheap Chinese mgn12 rails from aliexpress cost 20$ each.
The store i bought it from named: "Mellow" via aliexpress. Before that i bought from other store named: "linkcnc Store" and the rails was awful! it was a used rails, damaged and shorter then what i ordered. They ware so awful, that even after cleaning and lubricating it was still stuck and jammed.

Cleaning and lubricating

notice that the mgn rails you'll get will not be smooth as it should be.
at the factory they lubricate it with a protecting oil that need to be cleaned away.
There are some videos on YouTube showing how to clean the carriage with WD-40.
don't forget that after cleaning both rails and carriage, you will have to lubricate it with sewing machine oil.
As for smoothness: Please ignore the method for testing smoothness but tilting the rail - its wrong! You want it to be smooth but not too much.
Also, since its a miniature rails, please don't use thick grease to lubricate.

Adittional links

Cleaning mgn12 carriage video:
Although the video in russian language which i don't understand - its a pretty good video. just use a container in order not to lose steel balls

note: after assembling all steel balls, you will be left with empty space of one steel ball.

Rails installation:


  • fixing the rail can very frustrating, you will have to re adjust it a few times until the rail will be leveled and straight.
  • the mgn bed adapters needs to be fixes with screws to the heated bead carriage - screws must be tighten in cross like in anet a8 manual.
  • take your time an adjust until it will be even from both sides then the motion will be smooth.
    its very tricky and need a lot of patience.

Small demonstration video

Note: The motor in the video is incompatible. it was installed only for taking the video and testing the weight.

view original size: open it in a new windows and save the image or use the pdf file inside the zip files

view original size: open it in a new windows and save the image or use the pdf file inside the zip files

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You should design a direct feed bowden extruder (with bl touch) to fit onto this rail upgrade. Im hesitant to attempt this upgrade because the bowden tubing makes it extremely difficult if not impossible to print in flexible plastics...

Hi, i am working on it :)
I have designed a prototype and i am wating for the Titan extruder to arrive.
After i will make sure it works well, it will be released :)

Comments deleted.

Hi .Im ned bigger printing place like 400x400 .What im must change on this project ?

Looked around but couldn't find any information regarding the Y carriage adapters you made.

Think about ordering a new Y carriage:

Will those hole dimensions work out of the box for these adapters? :)

Are you talking about the dimensions of the Anet Y carriage?
If so i can upload a simple sketch of the adapters proportions

Yea, just wanted to know if the holes in the carriage would match with your adapters for the MGN12H.

Ok :)
I made a sketch with the requested dimensions (attached)
The 20mmX20mm is for the mgn12 carriage and the second set of holes is for the Y-carriage

Hy there...cool design, in fact I've decided to build this one, in all black 2040...I will build the 500 mm Z version and I need to ask you the changes that I have to do in skynet...I need some numbers I think. ..can you help me?...

Thanks a lot for your mod...

You did an amazing job !
I'm currently building one and I have a questions :

  • Could please tell why the hole over the X motor cover is for?

Do you mind to design a MK3_V6_hugger for a 40mm fan (30mm fan are too noisy)? I tried by myself and I definitely have no skill in this...
Thank you and once again, GREAT JOB !!!

Hi, Thank you :-)

  • As you can see at the posted pictures the hole is actually more like a channel to hold a 12-10mm PVC pipe that contains the cables.
  • You can try using a 40mm fan adapter of it (many adapters available at thingiverse)

On a couple of your pictures / renders and in one of the videos you have a green piece on top of the blue x motor part that looks to route wires, but I cannot find that stl in your files. Is that available anywhere?

You can find it in the files,
The name of the part is "X-motor_cover.stl".

This is amazing! I'm slowly assembling my own. I was wondering how to use the "Anet Extruder adapeter Beta". It's unclear how to attach the belt. I see two small holes (not the mgn12h ones) and was wondering if there was a part that supposed to screw there to fasten the belt. Should I just "ziptie it on" or is there something better?

Hi, thank you !
secure it with help of 2 zip tie each side and on top of the two screw install the x-belt holder which secure both screw heads.
I prefer the zip tie option other then the fixed adapters

Здравствуйте, это полноценный проект принтера или доработка?
смогу ли я по этому чертежу сделать принтер?
зарание спасибо)

The STEP file contain all the parts needed.
You can also find the basic manual at AM8 thingiverse page.

Hello guys, I was thinking about making this "improvement" to my machine.

In addition, as I´m fully disasembling it, I want to increment my printing size with a bigger bed (300x300mm).

However I can´t find in any store the bed platform. I did found this ( http://store.thingibox.com/es/laser/206-base_300x300mm.html#/tipo-metacrilato_8mm_negro ), but it is made with 8mm methacrylate and it is heavy for my 200x200mm version so this one must be so much heavier... And one more thing, it fits linear rail rods, not lineal guides as this printer or 2020 aluminium profiles for the other printers as Creality, Tevo...

So if anyone knows where I can find it I would really appreciate if I can have those links :)

You have to update pdf with part to rpint abs and pla and suggestion settings :D

The blue parts are PETG/Abs and the green ones are pla :)
But he also included one file with print instructions

not about new pieces... ;)

Would you be willing to add a E3D Titan Aero Carriage for this, or would the v6 one be compatible at all? I was hoping to upgrade to one of those when I do this conversion.

Right now i am working on a Titan direct drive carriage, as for the titan aero - it depends how well the titan carriage will preform.

Hey and congratulations for this nice mod!

I'm atm planing to build one, i have here a 220x270 Heatbed, i want to go with the 270 site on X, so the bed travels on Y still the same way.

Is my planing right, that when i change the 3 x 2040 extrusion 313mm to 363 and the X extrusion + rail 50mm more, than im fine?


Its seems to be just fine..
Wish you enjoy building it :)

Hello, where have you buy the rubber feet, please ? They look great !

i printed cyclops carriage mount but not fit my
could you make a version for this?
maybe a mod of your chimera carriage like this in picture whit space large 30mm and more long the support

whats the best material to make these parts out of?

will PLA work for any of them?

The best ideal material is Petg.
However some parts can be made from PLA. Inside the zip file of this design you will find a PDF with full
description how to print those parts. You will find there full info such as: Material to use with each part, infill percentage and so on..

Love the design! Rails are getting flown in from China already!

One small question would hate to go away from my direct drive.
Are you looking at creating a direct drive mount or did someone else already make some? :)

Great work!

Yes, I will start working on this soon..
First i want to upload a new updated 2-3 versions of the carriage and some other improvements (very very soon).
Personally i am considering adding a Titan Aero.

What are you using for those wire wraps?? I like them a lot

Hi :)
i have wrote it couple of time before, Its "PVC Flexible Corrugated Cable Protection Pipe".

If anyone is interested, I have added BLV mod support to my modular x-carriage design: https://www.thingiverse.com/thing:2599692

Modular X-carriage for ANET A8 / AM8 / BLV

Nice !!! great work !!

WOW all black..
I see you have made a custom plate - its seems to be very solid and rigid. Nice!

Thanks! All black petg.


My own design. Will update the thing with BLV adapter mount after some integration. I already see a few things that need fixing.

Modular X-carriage for ANET A8 / AM8 / BLV

Extremely Modular :-)

what are
I cant find in pdf

Those are new parts that designed after i made the pdf.

Feet - Small feet that you can add to extrusions corners. it has a hole for the AM8 rubber feet.

LED clip - if you want to add led strip, although you can just slide the led strip inside the extrusion without problem.

X-motor cover - its a cover for the x-axis motor. It will protect the 16t wheel and belt. You can add a P.V.C flexible pipe to hold all of the electronics. (Check my photos of the printer i built).

This week i hope to add a big update (more carriages and options) and refresh all the pdf.

hello Blv, i am in the process of making this awesome mod, i was wondering a few things. Did you see au real ( like a huge ) improvement in quality of prints and noise ?

And the second question, and its not 100% related to your mod but, if i want to make the bed bigger, can i reuse the stock board of my anet a8 and just change de configuration file ?

Anyway, this is a huge work, you a monster thank you very much for sharing this.

EDIT : i forgot, i want the bed 200*300, i already ordered my mgn rail and they are all 400mm long. I think it will be alright. For the aluminium extrusion, i just need to add 100mm on all the X axis ? Thank for you help !

hello, I copied it as far as all goes well, do not get the configuration.h,
they have a ready configuration.h for Ramps 1.4 mega2560.

Thank you very much

x motor mount dont need support for small part go outside?

Yes, you will need a support for this part :)

it's the only one? becouse i read nothing in the project about it :(

You are right.
unfortunately, with thingiverse platform i'm unable to choose what part requiter support and which one doesn't. But i am thinking on making a new PDF that will include this information. However until then, if you see a part with a hanging section, just add a support and i promise to work on a new PDF after i will finish the new carriages testing
Thank you

Printed tonight for test the xmotor mount in ABS with this settings (S3D)
15line brim
80mm/s speed
and obvisiouly... support
seems ok

good morning, congratulations for the project. I'm building a printer like yours, but I can not read the measures in this file because the photo is too small, could you enlarge the photo to make it readable? thank you

Hi and thank you :-)

The dimensions PDF file can be found inside the Zip file (not an image format but PDF).
Also please notice that the space between the bottom and the Z motors mount depends with your height of you coupler. With my printer i placed the Z motor mounts very close to bottom of the extrusions.

ok, thank you, I did not see it, now I can continue with the assembly

Hi Blv.

One question,
i am wondering, how did you fix the rails to the extrusion profiles?

With the standard square nuts?


Hi :-)
With an M3 T-nut / T hammer nuts.

hello what are these green hoses and where can I get them?

I have wrote it a few comments below:
"...pipe called: "PVC Flexible Corrugated Cable Protection Pipe".
the only problem is that it usually sold in 1000m rolls for contraction.
I found mine while walking down the street and saw a hookah store.
apparently, its pretty common to use those pips as a hookah smoking pipe. the seller was pretty sure i am crazy,
after i told him i could use a hookah pipes for my 3d printer.."

I bought mgn12 rail to make your project little be bigger... 30x30cm bed... but i cant find a way to how clean it in youtube :(
did you changed the steel balls? becouse the only video you linked is to do that... (which is the right diameter of balls ??)

Hi :)
I have not changed the steel balls, just cleaned them with a de-greaser (WD-40) and oiled them with sewing machine oil.
just be careful not to lose the steel balls! use a container to disassemble it so you will not lose them.
I have found a good video demonstrating how to clean the mgn carriages (i am NOT speaking Russian, but the video is very good and can be helpful).
Video: https://www.youtube.com/watch?v=luonzoH-xwQ

Awesome design my friend! I have everything but the rails which should be here today. One question... looks like you printed your cable management 'springs'? I love those things, but I can't seem to find a link for them.

Thank you :-)
Actually It's not a printed spring but a pipe called: "PVC Flexible Corrugated Cable Protection Pipe".
the only problem is that it usually sold in 1000m rolls for contraction.
I found mine while walking down the street and saw a hookah store.
apparently, its pretty common to use those pips as a hookah smoking pipe. the seller was pretty sure i am crazy,
after i told him i could use a hookah pipes for my 3d printer..

Da pra usar mgn300mm no eixo x?

I'm afraid 300mm is a bit smaller than needed.

I almost have all the hardware! Just waiting on the rails!

I'm having trouble printing the y carriage adapters. Two of the hex bolt holes are printing without a wall leaving it open.

I think it's because it's counting the text on the side in the walls but despite reslicing, no dice.

What slicer do you use and how many walls are you printing?

jpg is a picture of the carriage adapter

I am using Simplify3d and 3 layers walls for the Y-axis adapters and it closing the adapter walls. (actually, i am using 3 walls for all the parts that needs to be extra strong)
However, You can use it without the external wall, the nut hole are there just to hold the nut locked.
Please don't forget to scrap out the hanging material (the curly petg leftover in the nut hole), the nut hole should be flat, else the nut will stick out and it will not be straight.

Thanks for the heads up. I'm still struggling with the petg and I'll most likely reprint these. If you have a moment, would you be willing to slice one and post the g code just so that I can make sure it is the slicer? I'm looking for an excuse to buy a s3d anyway.

Problem solved, Check out the new improved adapters (thing updated) :)
I tried to slice it with cura and saw the problem. Any way, i moved the text to the other side and made the outer wall 1mm thicker.
Now, you will not have any problem to slice it and get a perfect adapter :)



Hi, first of all, really cool design, kudos!
I've been using the standard AM8 for some months now with genuine e3d v6, marlin firmware and my own x-carriage design but got a bit bored with it. Everything works great and constant fiddling/upgrading stopped.
I was thinking of buying original Prusa mk3 until I saw your little monster. So instead, I ordered the linear guides, additional profiles and can't wait to get rid of cheap Chinese 8mm rods and start building!

I think I'm addicted to these printers. I haven't even finished crafting my first AM8, and I've already ordered parts for this mod so I build a second one!

I've had to shift to a capacitive sensor for autoleveling due to the inductive sensor having a hard time seeing aluminum through 4mm of glass. Once I get that dialed in on my original A8, I'll finish and setup the AM8 to print the parts for the BLV mod.

And Rover31 beat me too the punch. I want to build a 400 X 400 based printer next, hopefully based on the BLV design!

Great design though. I look forward to building it. I'm thinking of designing a carrier for the E3D v6 that has all the mounts for the autolevel sensor, cooling fans, etc., unless one of you has already done it?

Thank you :)
Glad to tell you my friend, that I'm close to release a new carriage locker which allow you to use
Mistral fan, Semi circle fan and full circle fan. along with an adjustable bl-touch/proximity sensor (8mm/12mm) holder :-)
meanwhile skip printing carriage and the locker (on the next couple of days i will upload a new updated version)
I will update you after i will finish..

"Mistral 2.1" Extruder Cooling Duct for the Anet A8 Printer
by Leo_N
Semi-Circular Anet A8 Fan Duct
by lokster
Hesine M-505, Anet A8 - Center Nozzle Fan
by Arjjck

great design and idea. I am deff leaning this direction!
So how do you think it would be to incorporate a larger build into your design? Something such as this,

Thanks for your thoughts!

AM8 Large Print Volume 220x320x290 (Enlarged Bed)
by thaug29

Thanks :)

Since it a modular design - No doubt..
Only you will have to get a bigger rails for axis's and bigger extrusion for the x-axis.

May you include a direct driven e3d titan x carriage mount? :)

dude that thing looks so sick. major props to you

Thank you my friend !

How important are the screw head types? Are there any specific spots where a button head could not be used in place of a hex head? Or vice versa?


The head cup goes for the Z motor mounts and you can see the the exact location at the
AM8 manual - its wrote inside the AM8 manual

AM8 - Metal Frame for Anet A8

From the looks of things, the original printer was basically a source of hardware (extrusions, belts, PSU, electronics. Do you see any reason why this printer could not be assembled from scratch? In other words, was anything you used out of the A8 custom and unique to the A8? Thanks.

Well, you are absolutely right !
Basically, you are totally right. you can take your own hardware and fix it into this design :-)
The only things that should be the same is: 16 teeth idler, check if bed carriage fits and standard nema stepper motor with same size as the anet a8 motors.

Now that is perfect. That just means I can move forward because I have a ton of parts here! Thank you.

Extrusions and rails ordered... Should probably start printing stuff at some point.

Nice !
Have fun building it :)
it takes a lot of patience with the carriage cleaning process but it worth it.
The precision and print quality is definitely noticeable !

Hey Blv,

Your TR8 nuts do they have springs? Mine came with spring and be damned if i came just get the nut in let alone the spring too.

Yes, my TR8 came with anti backlash parts (spring and another small part).
In my case the anti backlash kept jamming the Z-axis. I took it out and
I like the results.

Since installing the rails might be tricky, I wonder if a 3d printed alignment jig would be helpful...? Totally looking forward to 0 wobble on my Anet. Thanks BLV.

Update: added 2 types of Jigs for 2040 and 2040 :-)
Thank you mate !

Awesome. Cheers

Yes, you are totally right.
I will add a jig :-)

hi, that's a great project.
I have printed all the parts and start building now

whar fan duct you have mount?

can you give us a link for it?

Nice !
I have used the radial fang fan from here:
Notice that you need to get from there the stl for 5015 fan.

Radial Fan Fang
by Lion4H

Hello what is the space who seperate the front and the back block, please ?

Hi tull :)

The space between the Back of rear extrusion and back of Z extrusion is: 119mm
inside the Zip file you can find dimensions.pdf file that contain all the dimension.
Please notice that i need to fix one error there: the Z motor mount should be pushed down until it will touch the Bottom_Tee_Plate

119mm behind adapter front and rear, i ask that, it's to adapt it for my 300*300 bed mount support, thanks.

i'm doing the same, which size you used for X and Y extrusion profile 2040?

Hello, I added + 80mm because the original heating plate is 220mm and the one I put is 300mm.

I found printing the z motor mounts caused it to warp for some reason using PETg. Couldn't get it to print successfully so i sliced with 4 perimeters and 20% fill and these guys are solid as a rock. Not sure if 80% fill is needed. Takes like almost 6 hours to print each one but they are almost done now.

Hi marcbea
If i am not wrong, Petg should not warp unless it has high humidity percentage.
Any way i hope that the 20% will work and 4 external walls will increase the rigidity of the part too.
I would appreciate if you could please share your work after it will be finished :)
Thank you :)

Yeah brand new roll just opened it. Filament box is at 30% humidity so should be fine. Yeah the part i did print is super rigid and fits perfect on the extrusion. Was so amazed last night when it started to bridge on the reinforcement parts for the z motor mounts. Not a sag on almost an inch distance. :)

What are your print settings, retraction distance and speed? I just ordered petg and I'd love to have a baseline to start from!

Here are the details

Print speeds and quality:

0.2mm @ 40mm/s
5mm brim
20% infill
4 walls
Top layer 2 Bottom 2


4.5mm @ 60mm/s


Hotend 235c
Bed 55C

Touch of hairspray on the glass bed does a great job if you have your leveling tuned. Print on of the x holders first to check your dimensions and hold sizing to make sure you don't have to tweak your printer first before doing hours of printing. Forgot some details above so added brim infill and walls

That sounds like hard learned experience. Thanks for the heads up

Once again, thanks Blv.

Getting closer to my next upgrade for my Ranita AM8 https://www.thingiverse.com/thing:2462104 , as the MGN12 rails with MGN12H carriage arrived from Aliexpress. I bought them on their 11.11 sale

2x 400mm https://www.aliexpress.com/item/12mm-Linear-Guide-MGN12-L-400mm-linear-rail-way-MGN12C-or-MGN12H-Long-linear-carriage-for/32837995749.html?spm=a2g0s.9042311.0.0.ASiIHB

3x 350mm https://www.aliexpress.com/item/12mm-Linear-Guide-MGN12-L-350mm-linear-rail-way-MGN12C-or-MGN12H-Long-linear-carriage-for/32838019510.html?spm=a2g0s.9042311.0.0.ASiIHB

All rails where well padded, sealed in plastic, covered in machine oil. ~ $78 shipped for 5 rails.

Slowly printing out parts...

Anet AM8 Variant
by ranita

Have you unpacked and inspected your rails yet? I'm ready to pull the trigger, but the seller has subpar reviews (only 15 reviews total) and one complaint specifically about the rails.

Agreed with blv, they will need cleaning.

I have only unpacked one of the rails to inspect and it seems fine. I inspected the others through the plastic and they seem fine too, no wobble due to missing balls etc. I am not an expert, but it slides smooth despite all the packing oil.

Thank you very much!

Did you get them to combine shipping? It's looking like $86 total right now. Oh, and I think his price went up a dollar from earlier today.

WOW ! this is actually a very good price !

It looks like all 5 axis plus two additional carriages will run about $100USD shipped. Not sure how Artistebot pulled off $48.

Nice !!
Don't forget to clean the mgn12 carriage carefully. dissemble them inside a plastic container so you would not lose the steel balls.
I have found a good video demonstrating how to clean the mgn carriages (i am not speaking Russian, but the video is very good and can be helpful).
After you will finish i would love to see your creation :)


Some people have used HBLFSDW5 brackets which connect to both slots instead of just one.


Have you found any instability related to only having the bracket in one of the two slots? The above 20x40 brackets are $3.50 each. I would rather forgo them entirely or at most, just double up the single brackets.

Hi KarmE,
Actually the one slot brackets are quite good. For the Z extrusion you can use the double brackets and it will hold even better.
Notice the inside (for the extrusion below the Y-axis mgn rails you will have to use short/one slot brackets).

First of all, wow, thank you. You brought some serious game to the AM8. Thank you.

Question about the Y Axis extrusions. Pheneey uses 340mm and you have 364mm.

Am I overlooking something?

Thanks again for your contribution!

This Question was already asked (And I just discovered) by user Mycroftholmes on Oct. 22 and subsequently already answered by BLV. To save some scrolling, the short answer is Pheneey's design shorted the bed from the original Anet, and BLV's extrusions restore that loss. I'll delete this comment if people think it junks up the board or if I misinterpreted the answer given

Thank you my friend !
Please don't delete it, i think it can help others.

Good luck building it :-)

Comments deleted.

I realy like your Modification and want to rebuild it. I have only one Problem with the Mesures , because i got a Coocheer A8 with a 220x270 mm bed and 270 mm height print volume.
4 x 2040 extrusion 364mm (Y-axis) i will change to 4 x 2040 extrusion 414mm (Y-axis), because my print bed is longer than a usual at a anet A8?
I would be thankfull for help, to step on with that nice Build without cut or order wrong mesured profile parts.
Height will be ok, usual i can upgrade the linear rods later.

Theoretically it depends on the bed carriage more then the bed. I can try mesure it to see if you will need a 450mm mgn rails
Do you have any sketch and domension of the bed carriage

The H carriage of my Coocheer A8 + is 21,5 cm Long and 22 cm Wide. Plus my justation Screws lets say 23 x 23 cm.

Oh i am sorry for the delay
saw it only now, i will try to simulate the carriage and tell you :-)

So i need to try on good luck now, or could you say please if your 22cmx 22 cm AM 8 has the same 22cm H carriage too, in both directions?
My A+ heatbed overlaps the Ends 2,5 cm up and downside. Maybe i need to give it a try and hope for, not to knock against the frame.

No Problem, i where busy too. 23x23cm H carriage and 22x27cm bed. Height is 27cm, but i wil incease it up to 60, i think so.

I am not sure but i think the H carriage is the same like the normal 22x 22 cm heatbed Anet. Maybe i wil get problems with my extended Heatbed which is 5 cm longer than usual, thats why i ask for.

I think i found a sketch of it and looks the same, but i can't guarantee that because its very difficult to find the correct dimensions of it.
is saw at list 4 different dimensions for the same carriage.

My lead Rod for the heatbed is 44 cm long, does that fit ?

If i understand you correct, you are talking about the Y-axis movement. Then, You will have to get 450mm rails

Still having a Diamond hotend laying around which i plan to use with. Is there any chance that you could create a Diamond Hotend Holder or do i need to tweak them together myself? the diamond Hotend is 8 cm wide and needs a bit more space.

That MGN12 Rails hurts in the pocket. 4 pieces 80 euro :D goin on.

if i am correct i need 5 rails plus 7 Slider and not 7 whole rails with 1 slider ?
Urgs, maybe i need to cut one down to save Money.

Hi Felix
Only the 2 rails for the heated bed has 2 carriage.
Here is the List:
Z-axis (Highet): 2 rails + 2 carriages
X-Axis (left<>right): 1 rail + 1 carriage
Y-Axis (heated bed): 2 rails + 4 carriages

it works just fine with 3 carriages on the bed :P

Yup, it will work well.
Two of my rear bed carriage less tighten and it working just fine

So i bought One rail to much now. 4 x mgn 12 400 mm. In Need for the two Y Axis mgn Rails 450 mm longer in case of my extended Heatbed.
One 400 mm mgn I could cut down to 360 mm but I can't expand their length really well.

where in the USA are people getting the Mgn12H Carriages?

Comments deleted.

You can find mgn12 rails on amazon / aliexpress / ebay

So do I need 2 440mm extrusions even when not changeing size?

I just got my am8 frame and don't want to buy more extrusions unless nessesary I see you mention option 1 won't change size but still needs two extrusions in the bom

If you want to leave the original AM8, you just add two exteusion (on the Y-axis) for the y mgn rails + brackets. Rest of AM8 extrusions should be the same..

Comments deleted.

Nice, that's taken it to the next level.
thanks you

Thank you my friend !

Very Nice! I don't have the time right now, but if I'd upgrade my A8, I'd do it your way.
Kudos for releasing the step files!

Another 3D-Printer working with linear rails is the cetus. You might look at the belt-management which i really like!

Thanks Thorax :)
I admire the clean setup of the cetus printer !
At first, i designed a belt system running inside the aluminium extrusion, but after couple
of hours i noticed the belt was to close to the extrusion core. Knowing that bigger wheels
such as 20T decreases the accuracy - led me to design an open lifted belt system..

my friend that excellent work, I mounted an original am8 and wanted to replace with MGN only the X axis, but I see that its parts of the X axis are attached to the Z axis what solution?

Thank you mate :)
Since it is a modular design, you can try and use thaug29 2020 X-Axis 2020 mod.
Then try to add the X-axis parts from the mod i designed.

Anet A8/AM8 2020 X-Axis 2020 for E3D V6/Titan Aero
by thaug29

Entendi, obrigado!

Hello, for what groove you have make the parts 5 or 6 mm

All the parts that fixed to frame are 5mm (hole)
Some internal parts with m4 and m3 (not to the frame).
You can look for it at the am8 manual and the bom file.
As for the other m3 & m4 all the description its attached as pdf file.

Y Axis question: I currently have an AM8 and used the 364mm extrusions on the sides as per the AM8 variant. The two new 364mm extrusions are held in place by alum corner brackets?

Thank you

Yes, the two 364mm extrusions below the rails are held with corner brackets (two brackets each).

That's all I needed to know, thank you!

First of all: WOW, you put really much effort in this, not only for building it but also for documenting it well!
Thank you a lot for this, also for the hint on how to get the china mgn12 rails to properly work (will try that asap).
I want to build this from my own custom made prusa i3 and have recently ordered a mk42 bed, has anyone tried using it and will it fit and be usable in all its size?

Thank you :-)
The bed used in the project is 220X220, I dont think you will have problem using 250X210.
For 300mm bed: it will fit also but the hotend will not reach the edges unless X-axis size increased.

Whenever this thing is completed? I'm looking forward to it and i will definitely build one! <3 <3 <3
Thank you for build and share that with me and everyone!!!

I have built it already :-)
A few things left to do.. such as installing BLtouch, find center of bed, PID, calibrations and finding Best jerk / acc
Then i will post the results :)

Hi Blv,
You did a really great job here!!
And yes, a BLTouch would be really appreciated :)
In your file "BLV_mgn12_mod", green is for PLA and blue for ABS/PETG or it was just for the style?
Are pieces in STL files in the way they have to be printed?
thx :)

Thank you :)
The bltouch will be installed with fang fan (This fan has a built it sensor mount for bltouch and proximity).
You are right, all the parts colored green is for pla and blue for petg, but some parts can be changed according to user will.
I added now a few new parts:

  • new feet mount instead of the tapping method
  • led strip holder for top and x-axis
  • improved x-carriage

Right now i am working on adding higher version of mgn y-axis adapter.

Hi, thanks for this awesome piece of work. One question : In the BOM it says : 5 MGNH12H carriages but shouldn't that be 7 ? (4 for the bed, 1 for the X-axis and two for the Z-axis)
Thanks for clarifying !

Correct !
I thought i fixed it 3 days ago, but after saving i got "token invalid" on thingiverse site (too much edit time i guess)
any way i have corrected it now
Thank you very much body !!

Comments deleted.

Could you please advise the lengths for 2040 for the front, back and top of the printer. I could not see this on the BOM.

My friend
Its 313mm according to AM8 manual
as i wrote in section "Choose your Style" at the item description, first you will have to choose your style (Original AM8 OR extended Z height). then, since it's based on the AM8 you will have to download the AM8 manual from here.
i wrote. Dont forget to read the "what to print" section in order to know what to print from AM8 parts.

AM8 - Metal Frame for Anet A8

This is awesome, I am preparing to upgrade to AM8 soon.

Cool ;-)
It's a lot of work, but man.. what a difference !

Hello and thank you for sharing, I would have liked to know if a heatbed of 300x300 can be installed with the dimensions of the frame to 500mm?

Thanks :)
you will have to replace the 313mm (2040) extrusion and the X-axis (2020) extrusion.
if you will not do that, the V6 carriage will not cover the bed edges (Y-axis depends on the carriage size)

And on the y axis no change? I thought to extend 80mm both axes (frame and rails). The original bed is 220mm and the one I want adapted 300mm that's why 80mm.

It depends on the carriage you are going to use.
Give me a link to the bed carriage and i will calculate for you the Y rails/extrusion size :-)

I think I will cut a plate of aluminum 300 * 300 like the heated bed.

So will you leave the space between the mgn carriage the same?

I will use the mgn12h which will be fixed under the plate of aluminum then between the plate of aluminum and the heating bed, the springs and screws.

Yes, but before you need to calculate the Y rail length because the travel distance extended by 40mm each side.
The distance depends in the space between the carriage that holds the bed carriage. please tell me the space
between mgn carriage (rear<>front) then i will calculate what lenght of rail you will need for 300mm bed

In fact, I thought to take the distance proportional to that of the 220mm!

That makes sense :)

Oh yes! now here is a mod I like!


Thank you :-)

Thank you this is brilliant.
I do have a few simple questions though that being if i was wanting to do this build without making it larger and with using the standard extruder carriage what i the parts that would be needed? I have seen that you listed a Mgn12 350mm rail instead of the 400 for the standard build size am I just missing the other parts that would be needed?

PS get better need good designers out there...

Well ,i worked on something, check the attached images to this post.
The weight is still an issue and i'm afraid you will have to get a longer extrusion instead of the 313mm.
since the Original Anet extruder is very wide compering to V6 it will not cover the edges.
the adapter i made is only a prototype and i am not sure about it.. on Sunday i will be at home and check
again the measurements.

Thank you :)
you will need the 350mm rails, But for the extruder - i will have to make wight and size simulation of the original carriage.
if it will fit there, i will design a mgn12 carriage to Anet original extruder adapter .

I will update you :)

Honestly this is really stunning work that you have provided to the community. I wish you a speedy recovery. Many thanks for releasing the STEP files.

Dear friend
i really appreciate that, thank you :)

First, I hope you recover soon.

This is AWESOME, thanks for creating this. I recently completed the Ranita AM8 that turned out great. After I finish my MksGen1.4/Bowden upgrade might have to do this!

One suggestion.

The original AM8 LCD mount uses the Anet LCD, that when mounted on the front, would still fit within a Ikea "Lack Table" enclosure, mounting the 12864 will cause the AM8 frame to no longer fit (too long). I recommend the "AM8 RAMPS Full Graphic LCD Smart Controller Mount" by PapaJohn88.



Thank you mate !
I appreciate your excellent suggestion and will add your recommendation to item description.
also i am very pleased to know that my work can be helpful to you :-)

Thanks for the reply.

From the look of the images, your solution seems to be not any wider than the "stock" a8? The "other" v-rail,slot, open-rail etc A8 solutions seem to be wider, so they would not fit in a "Ikea Lack table" enclosure. BRAVO!

Why did you change the vertical (Z) 2040 extrusion to 500mm from 440mm? Since I have already built my AM8 frame with 440mm Z will it work with 350mm rails?

Thanks for the note on a source for the rails, as I thinking of buying the rails form Aliexpess "Cheaper the better" I was thinking but maybe not? One seller (wuhushiyu Store) says in their listing "NOTE: We can cut in any length of rail. Just do not hesitate to tell us your request."

PS: Found the "link cnc store" as they seem to be the only one that offers 360mm rail. The pictures show rails scratched and worn etc.

Thank you :)
I have changed it to 500mm in order to increase printing volume height
The main reason i am answering only now is because i made some simulations with a 440mm extrusion (original AM8 size).
at the end i found that 350mm mgn12 rails can fit there pretty good (measured it with a 350mm threaded rods).
Also, the drawing/sketch of the simulation attached to this replay message.
The 350mm mgn12 rails will fit just fine to the X-axis rail without any problem
btw: I think you should avoid buying custom size rails, they will cut it horribly.

Thank you!

Again, good work!

Hello... I bought all pieces to make AM8 ranita versión... It is possible to make that one but with same high of ranita one and not 500 mm?

Yes, it is possible.
the z rails can be fixed to a bit smaller extrusion.
As long as you will make sure to fix it well to extrusion. even if a small part of the rail will hang on air - it will work just fine.

hi again , i have another question , i would like to know if you have de 3d files of the pieces maybe in solid works , i do that question because i can machining some pieces in a machining center for doing it in aluminium ,and from the stl files i cant take the measures.
best regards

Well, since you asked so nicely..
I have uploaded the full Step file which can be edited with most of CAD software.
Enjoy :-)

hi,the desing is awesome , bue i have few questions,
in the BLV mgn12 mod PDf . i see 2x364mm profiles and 3x313mm and i the pom pdf , says 4x364mm profiles can you say me what is the real one for 220x220 bed ?. and another question , if i want to do a 500x500mm i must just add the resting 280mm from the diference of 220 bed ?

You are right and i will explain it:
In the original AM8 BOM there are 2 Y-axis size 340mm which was wrong, since it was less then the original Anet A8 y-axis size. as a result the pause function didn't worked. So, Another user (ranita) suggested changing the Y-axis extrusion size to 364mm in order to gain back the lost 2cm. in conclusion, You will have to buy 4 x 364mm Y-axis extrusions. I apologize for the messy pdf, in this case i made there 2 images: the first 2 x 364mm extrusion is for the bed rails and from right you will see another sketch with another 2 x 364mm extrusions.
Yes, you will have no problem doing it with 500mm the measurements will be divided excluding the bed size (you may have need to change the bed coordinates in marlin) i will be glad to add the right measurement or code after you will finish it.