EMT8 - The absolute cheapest metal frame for your Anet A8

by whisky_97 Mar 7, 2018
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I've printed everything and cut the tubing to length. I'm doing a test assembly on a scrap piece of tubing and one of the parts to see how they screw together. My observation is that #10 screws seem just a touch big for 1/8" holes. Is that what folks are really using? Seems like #8 screws might be better. Also, 3/4" screw lengths seem long. If you have back to back screw holes like in the Zbrace, you're going to have the front and the rear screw interfering. Looking at what I have, I'm not sure why 1/2" screws wouldn't be better. Curious others thoughts.

Thanks for this--I just got it together and replaced the cheap bearings with the spiral pla bearings (also found on thingiverse) Its way quieter and alot more rigid. I used to print at 60mm/s but am slowly going to move it up to see what a difference the frame makes. I read someone doing 100mm/s?

Menace6983, play around with it. I've been able to print over 100 mm/s (for infill and things that don't matter). With PETG, I've found the limiting factor is the ability of the hotend to heat filament. The printer starts skipping steps (you hear it thunk) as it isn't able to keep up. Nonetheless, 100mm/s on PLA is probably well in the capability of Anet A8. You do start to sacrifice quality as you approach those speeds.

How do you line up the Y Rod holders and y motor mount and belt tensioner?

I largely left the bed intact for the changeover--you can also use the original plastic frame to align the rods until you get the screws drilled into the conduit. Then pull them out and re-assemble.

Do you think it is possible to use mgn 12h rails with this design? I am in the process of printing all the parts right now. Thank you for sharing.

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I can't wait to get to building this design! My acrylic frame is starting to pull in on itself, so it's definitely time to step it up.

Is there any preferred way to cut the EMT conduit? I've never worked with it before.

Also, I had an idea of filling the tube with expanding foam to further dampen vibrations...would this likely have any effect at all?

Use a cheap pipe cutter, which you can get for under 5$, it works perfect. You could try to use expanding foam, but resonance through the frame is not really an issue (at least not for me). But if you do please keep me updated, I'm curious!

Where does Zbrace_2x go? I don't see it on the renders or anyone else's build.

Z Braces were added a couple weeks ago. I put a new picture showing how they are installed.

I like this idea a lot! Does it really make a big difference in print quality relative to the stock frame? I know a metal frame is supposed to be better; but I wonder how much it really matters with the other inexpensive components of the A8.

It does! My brother has an AM8 and our prints are identical. It is a huge upgrade over stock.

I noticed that the Y guide holders STL files are different from those in the photos, is it right?

Yes, the v1 were rubbish, those included in the files sections are far better.

Genius! I saw this just after ordering some aluminum extrusions. I will keep this project in mind. Thanks for sharing!


Thank you for your stuff. Now I'm going to expand the Anet A8 instead of throwing it in garbage!

But do I have a mistake or is it a misunderstanding:

You write that if I come from a metric country I should increase the pressure to 105%. There is no problem with the corner connectors, but at the latest when the engine holders are on the line, they either no longer fit on the pipe or the holes for the fastenings are no longer centered. If yes, I have to increase all parts 105%. Do I have a mistake or how is it in practice?

Look in the Remixed sections, there is a metric version called the AMT8, it should be easier than scaling the parts.

Is it possible to redesign parts to use 1/2" conduit and 10mm smooth rods? Just trying to use what I already have on hand

Of course it is possible, Solidworks and stl files are given for that purpose. But I doubt the structural integrity of 1/2''

Started my build... wish me luck!

Could this printer be designed with a larger build plate? Like 400x400?

Of course. Just make the x and Y extrusions longer. I am currently designing the EMT10, a 300x300x500 printer using 2020 extrusions as rails. Keep an eye for its release!

Is there some kind of formula for figuring out the length of pipes I would need for a bigger print area? Still kind of new to all this I was thinking using my A8 to build this but also wanted a bigger print area

This frame is built for a 220x220 bed, so if you want to use a 300x300 bed, add 80mm to all the x and y tubes.

Currently printing out in petg

The metal pipe i got is supposedly 25.4 but at 107% scale way to tight. Doing it at 109% which is coming up a treat.
Still tight but not impossible after light sanding. Could be just my printer slightly different etc.

Will post pics once done but will be while as going igus bearings at same time with new rods and printed bearing blocks

How hard would it be for you to remix this with a 12mm smooth rod system instead of an 8mm? I guess the actual Prusa x carriage pieces would need to be edited to hold 12mm rods too. With a 12 you could easily scale up and make a Mega prusa i3.

I have a mega prusa but my acrylic frame at that scale is terrible. I'd love to be able to reframe it with conduit like this but I'm absolutely terrible with CAD programs. Maya and zbrush is more my speed.

Found 12mm smooth rod x carriage pieces. https://www.thingiverse.com/thing:2710658/files

test part for 12mm z rods (updated)

I don't know if I comment in the right place.. but I've never seen 3d printer made from this steel, in my country this is cheap. I were not designer but just got my first anet a8 and would like to upgrade the metal frame.

Is this steel sturdy enough? Can i make the frame from this? Any advice or suggestion? I am by no means an engineer or designer but I would love to learn make the printed parts for this frame. I think FreeCad would be good.. I am still learning actually.

Thank you for this great design. I definitely love this design.. I'd build this in the future.

Hy Rudz, I'm pretty sure that is rigid enough, I build my 3d printer frame with some scrap 9mm MDF (way softer than that metal profile of yours) and it works pretty darn well. And if you are planning to build it as a cube (like in the second picture) then it will be really sturdy. Good luck with your build, cheers!

I was having a tough time fitting alot of the parts. Just realized author is printing in PETG which has very low to no shrinkage, where as I am on ABS and need to increase it by 1-3% on X&Y (Z shrinkage is kind of kept in control by layer height).

*Those Z motor mounts are way overly tight even after scaling. Everything else is fitting in. Can you update it to not be so tight?

Anyone tried to make this with aluminium EMT tubes? They are for similar price (europe) as steel tubes, much lighter, same strength, easier cutting/drilling/etc ... thoughts?

Are the pipe measurements the same for the RepRap?


I see that some of people want to adapt this project to Anet A6. I also want to do this. I usually used OnShape, and it could import:
Part files - SolidWorks (.sldprt) 1999 to 2018
Assembly files - SolidWorks as Pack & Go .zip files from 1999 to 2018

While I was writing this comment I saw that there are some files attached. Are those are compatible with listed above?

ok,, I got it all printed and all the EMT cut and put together about to start putting the printer parts on but where do you mount the limit switches at for the Z and Y

For Z you'll need one of these -- https://www.thingiverse.com/thing:1776429

The Y limit mount is printed as one of the Y Rod holders. It will actuate when the Y bearing blocks on smooth rod hit it.

Z Endstop Fine Adjustment Prusa i3 - Anet A8

oh ok,,, I missed the other Y block,,,, and I will go print it and the other you linked to me. Thanks

not sure what I did wrong. I printed all the parts and everything fits perfect except the upright pieces for the gantry. The holes seem to be about 1-2mm to small for the EMT. do you know the best way to size them up? I could just scale it up a little but then I think it would make the lower base parts to loose. Any help would be greatly appreciated .

The Z motor mounts are a very tight fit on the verticals. You could use a drill or file to expand the holes a little. It probably took me a couple of minutes each using a smaller drill bit to expand the hole.

I'm stupid.. If I wanted to maybe put a 400x400 or 300x300 bed.. Would I just make the tubing longer or does that open a whole ball of shit.

I haven't done it, but have looked into it a little. Would require smooth rods and belts for X and Y to match your bed size. I'm not sure the Anet board flashed with Marlin will support larger sizes, but I think it should. Your other limitation keeping the Anet board and existing power supply would be the 12V requirement for heated bed. I have seen some 300x300 beds at 12V, but you have to be careful as some are 24V at that size to limit current needed. Also the stock power supply is said to be undersized, and the heated bed is the biggest power user, so you'd probably need to upgrade power supply anyway.

I guess it is kind of a can of worms.

What tool do you use to cut the tube? Hacksaw? Or the copper cutter around 20-30$?

I just used a copper tube cutter for up-to 1 1/8 pipe. Yes, around $20 at Lowes.

I used a small metal saw and used a file on the edges

I think this is a brilliant creation. With so many others talking about using different tubing my mind immediately went to Steam Punk. Polish some 1 inch copper water pipe. Print the fittings with metallic filament. Add a few other punkish accents and you could have a retro Steam Punk A8.

Copper is waaaaaaay too soft to build the frame off. You could paint the steel pipe to get a better finish

Are you thinking of copper tubing that is meant to be soft for flared fittings? I was was referring to 1 Inch Type L Hard Temper Copper Straight Pipe. It's very rigid stuff even in its full 10' length. In the lengths used for an A8 frame, the difference in flex between it and conduit would be indistinguishable, IMO.

I like your idea of just spay painting the conduit. It would be cheaper and work well for the 3D printed fittings, too. Copper paint for the conduit. Bronze paint for the printed fittings.

Regardless, for $15 more than the cost for a 10' copper pipe a person can get an AM8 extruded frame kit.

EMT is galvanized. It's difficult to get paint to stick to it, but it can be done by using an etch. White vinegar can be used, or a commercial etching solution to remove any passivation layer.

I agree. I have had some experience spray painting galvanized steel. Etching is required.

for sh#@s n giggles i scaled everything to 120% and am almost done printing all the parts, some holes need to be re drilled due to the scaling but im printing at 90% infill. parts fit 3/4 schedule 40 pvc pipe that i habe filled with expanding foam. i reprinted the support bracket to make a small front support and it will have a 400x400 bed with 500mm height, i will most definitely post pics when its together!! thanks for this! it wont be my main printer, but it will still get plenty of use.

Can't wait to see this! It was my main idea to build the frame with PVC piping, but it way cheaper for me to get the EMT

Hi all, I am almost done printing all the parts for this for my A6. I have the pipes all cut and everything and I noticed that my smooth rods for the z axis are about 3 cm too short. I already compensated for the larger x axis length with the rods, but I guess the z smooth rods are longer and x smooth rods are shorter? could somebody give me the measurements for the x smooth rod length and the z smooth rod lengths on their A8s? I could find the measurements of all the rods, but not which goes to which. Thanks!

My z rods are 379mm

This would be great not just for the A8 but a scratch build as well. Absolutely brilliant.

Absolutely, all the stock parts are so cheap on Aliexpress. And it is easy to make a 400mmx400mm with this frame

I actually found this while researching a parts list for a scratch build. I'll be using a 15 inch bed, would I need to upgrade steppers, belts, etc.?

I'm new to this but would I just get a new bed at 400x400 or is there alot of adjusting?

About the scaling to 105% for us Europeans that use 25mm OD tubing, what about the display holder wouldn't the scaling mess up the mounting holes for the display and the buttons?

Your design is cool, I really like it.
I'm printing it 107% now, and I noticed that for the holes on top it'd be better for printing without support if you just add a thin layer (like 0.2mm).

I just started printing the parts. I’ll post a make once I’m done. Such a fantastic design!!

Is this of any use to add to the collection? I haven't printed it yet but you can drill 4 holes and mount any existing Processor case to it. I'll be using it for my GT2560 case for my Geeetech I3 Pro B rebuild. Call it a prototype! :-) Mike

You could try uploading it as a remix

When I've made sure it's okay I might well do that. :-)

I'm speechless. This is so cool.

Thank you for the compliment

Care to remix for some larger frames...can you scale em up for say a CR-10 sized bed (400x400x400)...and give us a howto on those
Call it the EMT8(XL)
400x400 heat bed
Saw somone on FB made one! EMT8
And yes..I think a front angled piece would aid in stability by ALOT!!!

I would really like to build this with a 400 x 400 build size.. Any luck?

I can't see any reason a larger size wouldn't work. The 12V heated bed electronics (and cost for rods/bed/etc.) would be my main concern. I haven't experienced anything to tell me stiffness of the frame would be an issue.

Other than the obvious of the frame being physically bigger could I use the same motors etc from a anet a8?.. Sorry I'm pretty new at this

From my limited research, the original Z rod and lead screws are 380mm and 345mm respectively. You'd need 500mm versions of each of those on the Z axis and both smooth rods for x/y axis as well. Otherwise if you get a 12V heated bed, the printed parts and electronics should be the same and work. The A8 is a good printer and great learning tool, but I'm not sure I'd put another $150-$200 in parts into making it that much bigger. I'm considering doing one axis - likely Y which will be in the $75 range after I get a 220x275 or so bed and smooth rod/bearing kit.

Oh cool. Thanks for the advice.. Just curious if you had to build a bigger print bed printer from scratch.. What kind would you do?

You'd just need to use larger piping to compensate for the bigger bed. I will look into the idea of diagonal brackets on my remix version of it as I think thats actually a good idea.

Nice design :). You may add small diagonal brackets to the top corners to improve X stability. It should not remove space from printing volume but will stabilize X against shifting left right.

printing the parts right now this is a bloody good solid frame ime from the uk and useing 25mm conduit tube available at any screwfix store for £8.99 for 3mtr scaleing up to 105% is a bang on nice push fit one bolted up this frame isn't going anywhere to me its got to be the best upgrade to do by far


can you update the solidworks parts with the correct ZMotormount?
I'm in the proccess of remixing it to fit 25.4mm EMT tubes.


The actual .stl file of ZMotorMount is in reality ZmotorMount and BottomCenter combined together. I made these parts separatly and couldn't figure out how to merge them in a solidworks part. So I merge them in a .stl

no worries i'l recreate it from the stl files.


Okay for you guys in Australia who want to have a crack at this, I had a piece of 25.4mm "Rod Chrome Tube - 25mm x 2700mm)" left over from the MPCNC project, and printed up a Front Right Corner piece at various percentages over stock, and 107% is a nice tight fit without being too tight that the part will crack because of the pent-up pressure on the part. So, there is a starting point for you all. Naturally, you will print your own test part, because every printer is slightly different, but this works for me and the tube selected. https://www.bunnings.com.au/sandleford-25-x-3600mm-chrome-tube-rod_p4821932 ... $26.20. :-)

Can someone upload some pictures once they've completed this? I'd love to see how much better the printer is with 15 dollars worth of metal.

I posted a Made of the machine!

Dude that is bad ass...and scaleable!!!!! Imagine a 500mm Z and Y...there is a video floating around on FB of a guy that modded his A8 with a 1M tall Z and 1M long Y, printed a whole model airplane wing, not in parts!

So very cool...and cheap...awesome!!!!

Agreed! This would be a great way to get to that 310mmx310mm Ultrabase I want to use.

Looks awesome...great job :).

so, have you already build one?, looks really nice :D

I posted a Made of the machine!

Awesome, I already took a look to those pics, looks really great and easily upgradeable and scalable, comparing it with your other printers, how sturdy you think it is and print quality?. If you could later share us a video of it working that would be awesome, I will build this machine definitely. Kudos man :D

It's better than the stock frame for sure and about 100x more rigid than my delta haha. I compared it to my brother's am8, it's not as perfect but once screwed to the plywood it is definitively a HUGE upgrade. Plus: it looks badass


Worth noting that 3/4" hardwood dowels would probably also for this printer, and they're cheap/easy to come by too.

You're right! And it would look badass in wood hahahah

Hi! Great job! It really looks great. Is there any chance for a 25mm tube version for the european folks?

I think you can get 20mm in EU? I think it is the same thing as 3/4" if I follow this spec sheet. https://steeltubeinstitute.org/steel-conduit/types-of-steel-conduit/electrical-metallic-tubing-emt/
Just be sure the OD is 23.4mm and you're good to go.

Doubt we can get the same.
I rushed to the store today and got some ø20 tubes (outer diameter = 20mm) before fine reading these comments. The other option @ the store was ø25 = 25mm outer diameter.

Guess an 25mm version would be a better option for us on the other side of the pond.

The nearest size in uk to 23.4 od is 25mm od our next one down is 20mm od so i think the 25mm oD is the better option for us

Hi, you have a photo of the printer on this frame

Not yet! I'm currently finishing up the last piece then I will put everything together

so waiting for it up to wear because the idea of Super

i have the anet a6. i think i can make most of ir to work, z axis motor mounts need to be changed the rest looks like it will.

Were you able to use this for the Anet A6? If so, what modifications did you make?

not yet. slowly learning meshmixer. or maybe could use 123design. once i have it printed at tested i'll do a remix of it. it could be awhile before completed.

Are you sure that the x axis rods can't just all be extended to about 331 mm? From what I can tell that would work, not sure if you noticed something I didn't.

the x axis has a wider track so they hade ro move z axis motors and guides out from main part of the frame. so o need to adjust both bottom z motor mount and the top part of z axis.

I just posted a remix of this for the Anet A6 if you are interested and have not already remixed it yourself. Called the EMT6

awesome! now printing. it'll me take a while.

All the parts should be the same between the A8 and the A6, both are using Nema17 motors so you won't have to change the motor mounts. However, I would check if the smooth rods are the same lengths.

it not the motors. x axis is wider so the z axis had to be move away from main frame, about 60mm from main frame to center of z axis guide post. mount plate is 82.5 by 62.5.

Oh I see. I can provide you with SolidWorks files I you prefer working with them!

i don't have solidworks , i use fusion 360.

can you share step or inventor files (fusion can export those) editing is needed for european use.

Fusion 360 can import solidwork files, or maybe whisky_97 can export them to iges or step.