Prusa i3 MK2-X

by davtr, published

Prusa i3 MK2-X by davtr Jul 27, 2016
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Prusa i3 MK2-X by davtr is licensed under the GNU - GPL license.

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MK2-X is implementation of most of Original Prusa i3 MK2 mechanical and electrical components into metal frame from RebeliX project. The goals are:

  • Significantly more rigid frame, which can be assembled easily and precisely.
  • Reuse as many original parts as possible, especially all X-carriage assembly with extruder.
  • Make basic parameters easily adjustable.

Frame is built from AL profiles 30x30mm (slot width 8mm), frame couplers and steel Y-rods are original from RebeliX project. Frame dimensions are 360x380x390mm (WxDxH). Y-rods are 360mm long. Profile lengths:
X: 360mm (3x)
Y: 320mm (2x)
Z: 330mm (2x)

Linear bearings for Y-carriage are replaced by their longer version LM8LUU. You can also use two LM8UU in row instead of one LM8LUU. You can even use only one LM8UU, in that case put it in center of bearing housing. But with longer bearings the bed is significantly more stable and rigid.
Top end of Z lead screws is secured in 8x22x7 bearings.
You will need some M6 screws and nuts to build the frame and mount printed parts onto it, and some M2,5 screws, M3 screws and self-locking nuts to mount MK2 equipment.

X-home position as well as geometry of Y-carriage can be adjusted by moving Y-rods.
Y-home position can be adjusted by M2,5 screw in Y-belt-holder under the bed.
Y-belt is tightened by simple belt tightener implemented in Y-idler (M2,5 screws).

See also http://www.thingiverse.com/thing:1898131 - modifications made for Igus RJMP-01-08 linear bearings.

Print Settings


Prusa i3 MK2






0.2mm, 3 perimeters, 3 bottom layers, 4 top layers


ABS 15%, PETG 40%


To print: 4pcs Y-rod-holder, 2pcs Z-axis-top (one mirrored around X), 2pcs Z-axis-bottom (one mirrored around X), 3pcs Y-bearing-housing, 4pcs al-profile-cover, 2pcs al-profile-cover-with-hole, 2pcs psu-mount-socket, 2pcs psu-mount-plug, all other files as one copy.

Don't print from PLA. Parts touching potentially hot surfaces (motors, bed, PSU) could deform if printed from PLA.

How I Designed This

  • All parts are designed to be printed easily from ABS without supports and without significant warping.
  • Regarding holes - usually if the hole is rounded, the screw should go easily inside, the hole might need to be finished by drill. If the hole is hexagonal, the screw is supposed to cut the thread there. Don't use drill on this type of holes.
  • Parts are designed with exact dimensions. You may need to do necessary adjustments to fit your printer and type of filament.
  • Some parts contain adhesion pads in corners (e.g. profile covers). They're supposed to be cut away by sharp knife.

Additional info

Current TODO list

  • Redesign Y belt tightener for more comfort
  • Maybe redesign Y-endstop mount, put Y-endstop on Y-rod-holder to avoid unreasonable dependency of Y-endstop and position of belt pulley on Y-motor.


Original Prusa i3 MK2: http://shop.prusa3d.com/en/3d-printers/59-original-prusa-i3-mk2-kit.html
RebeliX project: http://reprap4u.cz/rebelix/ (Czech only)


  • 2016-07-27 initial upload
  • 2016-07-28 added LCD mount, new supports replace original ones and all LCD assembly then slides into front rail of the frame
  • 2016-07-28 added Rambo mount
  • 2016-07-28 added AL profile end cover and cover with hole (power lines from PSU to Rambo goes there)
  • 2016-07-29 added assembly guide while still in memory ;-)
  • 2016-07-30 temporarily remover AL profile covers (need redesign), added PSU mount socket and plug
  • 2016-07-30 added new AL profile covers
  • 2016-07-31 finished conversion guide, added few photos of completed printer, cleared "work in progress" flag
  • 2016-08-31 made RebeliX build instructions permanent download link, added original RebeliX corner couplers source STL files
  • 2016-09-17 changed orientation of y-rod-holder
  • 2017-02-12 redesigned some parts to make them work with standard 3030 extrusion T-nuts
  • 2017-05-09 enlarged slots for 3030 T-nuts (was 8mm, now 10mm)
  • 2017-05-09 redesigned z-axis-top and z-axis-bottom: moved down 5mm to avoid colision of probe protector and Z-motor screw, added tightening screw to top part, added hole for adjusting screws

Brief assembly (conversion) guide

  • Assemble the frame using only AL profiles and frame couplers, refer RebeliX guide for details. It's in Czech language, but with a lot of images. You can do it. :-) You can find one at http://s000.tinyupload.com/index.php?file_id=04890953869356069651 Original file can be found at http://reprap4u.cz/navod-na-stavbu-3d-tiskarny-rebelix/ but their download link sometimes doesn't work. When assembling the frame, don't forget to slide in required amount of nuts. They will be needed later. Without them you will have to disassemble the frame to mount printed parts. Also remember that rear edge of vertical profiles should be exactly 115mm from back side of the frame as shown on page 13 of RebeliX guide.
  • Mount Z-axis-bottom (left and right, watch the orientation), tighten.
  • Mount Y-rod-holders, Y-idler, Y-motor-holder, don't tighten (will be adjusted).
  • Slide LM8LUU into housings, mount on Y-carriage, don't tighten.
  • Slide in Y-rods, snap into Y-rod-holders (adjust positions). Fix with zip-ties.
  • Check geometry of Y-carriage (should be parallel with frame), check movement (should move freely in all way in/out), adjust rods if needed, tighten rod holders a little to prevent unwanted moving.
  • Mount Y-motor with endstop. Tighten motor screws, not frame screw.
  • Mount Z-motors (watch cable lengths, longer to the right), tighten.
  • Slide X-carriage assembly on lead screws carefully.
  • Slide in Z rods carefully and stick them in Z-axis-bottoms until they touch motor bodies. You may need to use a little force.
  • Use M3x16 screws and square M3 nuts to assemble z-axis-top parts. Put 8x22x7 bearings into Z-axis-top parts and slide them on lead screws and Z rods (watch orientation). Tighten to the frame. Check geometry, should be perfect. Put M3x30 screws into prepared hole (see images), it will limit vertical travel of the extruder. You can use the screws later for fine-tune of X-axis level.
  • Lay the frame on side, mount heatbed on Y-carriage, mount Y-belt-holder.
  • Assemble Y-belt (path of belt should be straight), tighten a little using adjusting screws on Y-idler. Don't overstress Y-idler. It's a printer, not guitar.
  • Check if Y home adjusting screw clicks Y-endstop when in home position. If not, adjust positions of belt pulley + Y-motor-holder, or heatbed.
  • Return the frame to normal position and check the geometry of Y-carriage. Should be parallel to frame and approx. centered in X axis. Adjust by sliding rod holders in frame. Tighten. Adjust Y belt if needed.
  • Connect cables to Rambo and check function. Both Rambo and PSU are NOT mounted to frame at this step, just laying around to check function and fine adjust geometry. Watch the cables, they shall not collide with moving parts.
  • Check adjustment of home position - do Auto Home command. When finished, Z-probe should stay just above probing point. If not, adjust X by moving Y rods left/right (watch the Y-belt), adjust Y by adjusting screw in belt holder. Recheck home position and repeat until satisfied.
  • === The printer should be able to work at this point.
  • Place Rambo mount on the frame. The bottom side is where M3 holes are closer to edge. Align the height of bottom side around the height of heatbed. Don't put it too low, you won't be able to mount and close the casing door. Don't put it too high either, the cables aren't that long. In particular right Z motor cable is way too short.
  • Mount Rambo in its casing the same way as in Original Prusa i3 MK2.
  • Now comes the tricky part. You will need to replace power cables for longer ones. You need cables 75cm long. Remove black Prusa cover from PSU, drill a hole to bottom side so new cables can go out from bottom side on outer edge, approximately between mains socket and mains switch. Replace cables and put the cover back.
  • Mount printed PSU-mount-plug onto the PSU, use the same screws and holes as on MK2.
  • Slide in printed PSU-mount-sockets.
  • Attach the PSU assembly to the frame by hand all the way down (bottom side touches frame coupler) and mark the position of sockets on Z frame profile.
  • Remove sockets from assembly and mount them on the frame at marked positions.
  • Slide in the PSU.
  • Slide one AL profile cover (with hole) on both cables, put cables through rear traverse frame profile (via center hole) and fit the cover. Slide another cover on both cables on the other side and fit it on the frame.
  • Mount connectors on cables and connect power to the Rambo board.
  • Replace LCD supports by new ones, connect LCD cables at LCD side and then slide both supports into rail in front traverse frame profile.
  • Fit two AL profile covers on front frame profile, another two on top frame profile.
  • Finish cable management. I used some RebeliX cable clips combined with zip ties.
  • Done. Feel free to make additional gadgets yourself. :-)

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Are you using Orange EasyABS from Prusa Research to print your parts? Or something else?

My last MK2-X is all orange PETG. ABS is quite difficult to print without warping.
With PETG I use 40% infill to eliminate its elasticity.

Do you mind if you can share what brand are you using? The orange looks identical to the one that Prusa has.

The printer shown on the pictures is printed using orange ABS from Prusa. Orange PETG is a bit darker and more glossy.

My Y endstop does not switch properly... what I am doing wrong? I think pulley have small diameter...

Have you put adjusting M2,5 screw into y-belt-holder? See https://ibb.co/nBxqna

Hell no :D thanks!

Hi everyone
I remixed the extruder motor holder of the prusa i3 multimaterial, to fit the MK2-x 30x30 extrusion.
enjoy and happy printing


E-Motor Holder MK2x MultiMaterial

Could you please post a link to your spool holder? Would be nice ;)

can you make it for 10mm rods too? or upload source files please.

What is the reason for using 10mm rods?

Could you please explain function of screwholes in upper Z part? Thank you. V.

You can adjust horizontal level of X axis assembly using M3x30 screws in those screwholes. Just set the screws and then move X axis up until it hits the screws. It is part of XYZ calibration process in Prusa FW.

Hi, is there a way for me to resize the slot widths to fit a 6mm slot width? I wouldn't want to trouble you with it. Cheers

davtr - in reply to wsl

I'm afraid the easiest way is using another project based on 2020 profiles with 6mm slot. See remixes.

Hey davtr, just curious how old are you ?

Old enough for midlife crisis. XD

Sorry .... you're right, thanks

i noticed the particular psu-mount-socket.stl has the non-through hole.

i noticed the particular psu-mount-socket.stl has the non-through hole

And now try to figure out, how it would be printable without supports, if the hole was through. ;-)

What changes files (z-axis-bpttpm_v2.stl z-axis-top_v2.stl) compared to previous version?

See changelog in thing description. :-)

Hello davtr, I am printing the new Z-axis top and bottoms. What size screw is used on the top z-axis tightening screw hole?
My build is almost complete. Waiting on some additional Hardware as I am building from scratch.
Thanks again

It's mentioned in instructions. M3x16 with square M3 nut. Adjusting screw is M3x30.

Can someone with completed rebuild measure this for me please? Thanks a lot! http://imgur.com/a/HVzfG

42mm (with MK42 heatbed)

Hey guys, does ist work with the anet a8? Or are there different dimensions?

What type of stepper motor do you use?
Sorry my language is bad.

Apr 25, 2017 - Modified Apr 25, 2017
tusantrey - in reply to davtr

Can you give detail of stepper motor type you use? Example: Kysan 1124090 / 42BYGH4803, Rattm 17HS8401, and Wantai 42BYGHW609

What stepper motor do you use in making 3d printer above?


Detailed what are the 3d prints above? Is the print good? Or else there are other problems such as poor results or rough prints etc. Please give details clarity, because I want to recommend to my friend if this 3d printer is good in use.

Steppers are original MK2 which came with Prusa i3 MK2 kit.
MK2 does pretty nice prints, just see images in this thread: http://shop.prusa3d.com/forum/original-prusa-i3-mk2-f22/prvni-vytisky-na-mk2-t975.html

Hi! As a beginner in all this, I'm just amazed by your work! Thank you very much! I would be very grateful if you could link to all X-carriage assembly with extruder... i have not nothing yet :) Only expression and expectation of magic when I can immerse myself in the world of 3d printing :) I already ordered an aluminum profile and a printin' of the details that you so kindly provided. Now I'm dreaming of my own 3d printer and absorbing the abundance of information :) It's all so exciting!

Extruder and x-axis parts are available on Prusa's github repository.

Please note that this project is not designed for building MK2 printer from scratch. It's designed as rework of existing MK2 printer, you'll need some knowledge and experience to build new printer based on this design.

I understand, thank you! It's first that I truly like and I decided to build it )

There are missing M6 holes at Rambo mount i think?

There are missing M6 holes at Rambo mount i think?

After a glance the holes were found where they should be. :-)

Than maybe I am fool, but how to mount Rambo mount to the frame? http://imgur.com/a/A1TJN

Well, that's one simple method how to print the part without supports. ;-) After printing you remove that 1-layer helper by knife or 6mm drill (by hand).

Ah ;) now I understand... that 1 layer is only as support. I did not realize that it is only one layer ;). Thanks.

Where is the mount z-endstop?

There is no z-endstop, inductive probe does the job.

could you share your SketchUp files? I'm working on an enclosure http://www.thingiverse.com/thing:2252428 and would like to check all measures for my remix. Thanks.

Prusa i3 MK2-CUBE (integrated enclosure)
by dedalo1
Apr 16, 2017 - Modified Apr 16, 2017
davtr - in reply to dedalo1

The link is few posts back, look for "filedropper".

Excelent! thanks!

Have you designed a spool holder that mounts like the original or are you using something different?

Comments deleted.

Please read instructions carefully. Take z-axis-top, mirror (flip) it around X or Y axis and you will get required part. The same about z-axis-bottom.

Is there a version of the X Ends that use LM8UU bearings instead of the RJMP? I have a surplus of LM8UU's and want to use them. I have been searching but dont want to waste the hours printing just to find out they dont line up with the linear rod and lead screw.


All STL files for Original MK2 are available at Prusa3D github repository, including X-end and extruder parts.

Hi, I really like your adaptation of prusa i3 mk2 vs. rebelix. It's awesome. I had already built my own Rebelix but I would like to make some changes - right now I would like to reprint my Rebelix to this one. But I have a some questions - I see that I will have problems with flexible couplings for Z axes 5x8mm. Can you tell me if it is enough space between trapeizodal 8mm rod and smooth rod for Z axes? Or what is a distance between them? And next problem what I see is that due to change from original Wade extruder of Rebelix to the Direct Extruder I have a problem with homing Z axe because X motor is touching flexible coupling of Z axe first then I touch bed with my nozzle. But I will see how it will fit.. And my last question is which filament you use for this. I like this orange, I understand that is the ABS but from which producet if it is not secret. Thank you so much for this design is really awesome. ;)

Apr 5, 2017 - Modified Apr 5, 2017
davtr - in reply to mikymora36

see that I will have problems with flexible couplings for Z axes 5x8mm. Can you tell me if it is enough space between trapeizodal 8mm rod and smooth rod for Z axes?

There is enough space for flexible couplings, but there is another problem using them. Big advantage of using trapezoidal lead screw is quite fast and accurate movement of Z axis allowing to use Lift-Z feature (Z-hopping). But flexible couplings efectively deny that because of their axial flexibility. They cause significant backlash.

And my last question is which filament you use for this. I like this orange, I understand that is the ABS but from which producet if it is not secret.

It's orange ABS from Prusa3D. AFAIK original manufacturer is Plasty Mladec http://www.filament-pm.cz/en/?stranka=10&id=21

Ok, thank you so much for quick reply and your tips ;).

I fully understand issue about the flexible coupling therefore I must think about the reason why a lot of reprap machines using them? So what I should to do now? It's possible or not that I simply fix trapeizodal screw with motor shaft like "hard connection", without any flexibility? Or it is not so easy? Trapeizodal lead screw means that trapeizodal screw its part of stepper motor (it is connect directly to motor shaft) correct?

And I'm so sorry for my questiones because I'm new in 3D printing (roughly few months). However I'm trying to test new type of extruders, constructions, polymers, etc. and I would like to find better solutions for some weak parts of Rebelix, etc.

So thanks once again for your answers and time.

Jo a koukám, že budeš nejspíš Čech, tak možná bude lepší čeština. Ale zas nadruhou stranu, takhle si to může nejspíše přečíst (porozumět tomu) více lidí. Nechám to na tobě. Každopádně dík za rady.

Ahoj, na jedné z mých tiskáren jsem měl kombinaci klasických NEMA motorů a trapézových šroubů spojených pružnou spojkou a nedělalo to dobrotu při tisku objektů s hodně přejezdy a retrakcemi v kombinaci s velkou hodnotou Lift-Z. Na tom výsledku to bylo vidět. Originál MK2 má ty šrouby přímo integrované do motorů (tvoří jejich hřídel). Pokud se použijou kluzné ložiska, tak je to ještě markantnější, mají větší tření.
Použij pevnou spojku, klidně tištěnou, je to jednoduchý díl, který nakreslíš za 10 minut. Nejlíp to měl řešené původní Rebelix tou klasickou PVC hadičkou narvanou na osu a závitovku, pružilo to a zároveň to nemělo axiální vůli a jako bonus to skoro nic nestálo. Bohužel se to blbě realizuje, když motor má 5mm a trapézovka 8mm.
Nouzově se dá použít i ta pružná spojka, když se uvnitř dorazí osa motoru úplně těsně k trapézovce a když nahoře zajistíš, aby se trapézovka nemohla samovolně vysunout směrem nahoru (při současném natažení té pružné spojky).

OK, chápu rozumím. Já právě nepoužívám Z-Lift vůbec, zkoušel jsem to, ale jak říkáš nefunguje to - a teď aspoň vím důvod, dík moc. Já si právě zkoušel vytisknout pružné spojky pár dní zpět - střed je z Eco3D flex a spojky jako takově z ABS. Myslíš, že výsledek bude ten samý jako u klasických pružných spojek? Tam je ta axiální vůle dost markantní.

Chtěl jsem ti právě napsat i tu možnost jak vzpomínáš, že když dorazím trapéz v pružné spojce až k hřídeli motoru, tak se ta axiální vůle dost omezí. Jinak teda to rozumím, že nejlepší je to spojit na pevno. ;) Vyzkouším a uvidím jak se to bude chovat.

Tak jako tak dík za cenné rady. ;)

Apr 5, 2017 - Modified Apr 5, 2017
davtr - in reply to mikymora36

střed je z Eco3D flex a spojky jako takově z ABS. Myslíš, že výsledek bude ten samý jako u klasických pružných spojek?

To vůbec netuším, s tou konstrukcí a materiálem nemám zkušenosti. Ale kdybych náhodou tisknul spojku, tak ji hodím z PETG úplně jednoduše váleček s 5mm dírou z jedné strany a 8mm dírou z druhé strany, díry tak akorát nafest, aby se nemusel použít stavěcí šroub. PETG je dostatečně pružný sám od sebe a axiální vůli to mít nebude. Díry musí být dost těsné tak, aby tam šly ty osy z obou stran hodně ztěžka. Pak se to dá ještě pojistit vteřiňákem. Rozebírání se bát nemusíš, prostě to rozlomíš a pak stáhneš po nahřátí horkovzduškou.
Při použití stavěcího šroubu se to při utáhnutí deformuje a pak nemáš obě hřídele v ose. Dělá to dokonce i ta kovová spojka.

když dorazím trapéz v pružné spojce až k hřídeli motoru, tak se ta axiální vůle dost omezí

Ale jenom jedním směrem. Roztahovat se to může i nadále a je potřeba to zajistit na horní straně. Já jsem to řešil tak, že jsem před utáhnutím tu pružnou spojku trošku natáhnul, takže potom samovolně stahovala ty hřídele k sobě a roztáhnutí kladla poměrně značný odpor. Ale k dokonalosti tomu ještě kousek scházel.

JJ já ten flex jen chtěl zkusit, ale PET-G mám, protože jsem si část Rebelixe přetisknul z PLA na PET-G. S PET-G se mi dělá dobře a mechanicky je to taky jedna radost.

A s těma spojkama máš pravdu, já tam teď mám M5 závitovky a všimnul jsem si, že je to v té pružné spojce vyosené. Když k tomu přičtu stoupání a profil toho metrického závitu, tak přecházím na trapézy. Uvidíme snad se v kvalitě posunu zase o kousek dál...

This is very good! It would be even more Awesome if you put it on github as well, maybe together with the source files. Then changes you make could be updated and merged with custom modifications.

finally a printer i want to create!! looks simple enough!! all ill need is the aluminum parts and the rods, screws correct? i have ramps and all the motors and good stuff!! sorry first time builder of a thingiverse printer!! pretty happy i found this one!! tooks some diging on thingi

I like your enthusiasm but please keep in mind that this project was designed primarily for owners of original MK2 or at least MK2 upgrade of MK1. Of course you'll be able to finish the printer using other parts, but I'm sure there will be some issues you'll have to resolve yourself, which might be quite difficult task especially if this is your first build of 3D printer with no previous experience.

What extrusion lengths?

Hi will this work with 30x30 but 6mm?

Hi, what is version of extruder? You can send me the files? I need this to complete my project...

The hotend is E3D V6 full (no bowden version) and all extruder printable parts are available on Prusa3D github repository.

Hello! Is there any chance you could provide the source files for these parts?

My hardware store only sold 2525 aluminum and I would very much like to modify these parts to work with it :)


Thanks a ton!! I really appreciate your hard work!

Where did you source the 360mm rods for the Y Axis ?

Thanks for your reply... Yes, I know how to do a google search, thank you. I take it you don't have a recommendation based on your experience?

Hobby 3D printers are not a rocket science. Any hardened steel rods will be OK. Much more important is where are you from, actually I buy steel rods in local hardware shop, just because it's closest option.

"Any hardened steel rods will be OK"

Are you kidding??? I upgraded from chinese shafts to Thomson Linear Race shafting, and the difference was night and day.

How about you purchase some shafts from Aliexpress, and also some shafts from Thomson, and then you might be able to figure out that there is a HUGE difference between dirt cheap shafts and precision linear motion shafts. I would HIGHLY recommend against getting them from a local hardware store, and instead get them custom cut from a linear motion type company, any city would have a couple.

Your right, its not rocket science. Ironically you fail to grasp some pretty simple and crucial concepts. Don't be so smug and post "the let me google that for you", and then follow it up with a rude remark about rocket science, when you are completely wrong.

Is there a parts list if I wanted to build this from scratch without having an original Prusa i3 MK2 to get the parts from?

Great news. Thanks for the link.

I ordered mine and new I need to build new printer since my Prusa Steel is too small to accommodate this bed. I'll be taking Prusa Steel 2.5 as a base and extending X and Y axis.

Without original MK2 you won't get required heatbed. Of course it is possible to build similar printer using other parts, but you will have to find out how to do it and most likely modify some printed parts to fit the components you use.
Anyway, you can use online documentation from manual.prusa3d.com to find out parts list.

The new heatbeds will be available soon. There are 2 separate groups working on them right now.

Any links?

surprised he didn't LMGTFY.

Probably because there aren't any links. There is no MK42 heatbed alternative at the moment.

Hi, thank for you design, i am interested in build one for me. i Have some questions, do you have improvements in print quality? What are the significant differences with the previous printer about the print quality.

Please read the earlier comments. It has already been discussed.

Ok Thanks

Also redesign the stls for 4040 openbeam aluminium frame. I don't know how. Somebody ?

Any special reason for using 4040? Or 2020?
Why not 6030?

hi can i use 2020 aluminum extrusion instead of 3030?

Sure you can. But you will have to redesign printed parts. ;-)

Ahh okay thanks for the reply..

Mar 6, 2017 - Modified Mar 6, 2017

I really like this idea and i am looking to upgrade my prusa i3 mk2 to use this frame but i just want to get a few things clear:

  • Are my right in saying that these are the cut out dimensions for the Aluminium extrusion?
    X: 360mm (3x)
    Y: 320mm (2x)
    Z: 330mm (2x)
  • And the only extra equipment i need to buy to do this upgrade is to buy 360mm rods for the Y Axis and 3 LM8LUU bearings?
  • The fittings are connected with T-Nuts?
  • Why do i need new PSU cables?
  • Are my able to print these parts out in PETG?
  • Are there any adjustments i need to in the firmware or does this work as normal when i turn it on?
Mar 6, 2017 - Modified Mar 6, 2017
davtr - in reply to SchoolyBach

Are my right in saying that these are the cut out dimensions for the Aluminium extrusion?
X: 360mm (3x)
Y: 320mm (2x)
Z: 330mm (2x)


And the only extra equipment i need to buy to do this upgrade is to buy 360mm rods for the Y Axis and 3 LM8LUU bearings?

Yes. Plus 608ZZ bearings (8x22x7) 2x - optionally. Plus some M6/M3/M2.5 hardware (screws, nuts, washers) of course.

The fittings are connected with T-Nuts?

Yes, you should be able to use T-nuts with latest version of printed parts (updated Feb 12)

Why do i need new PSU cables?

Read instructions. Original ones are too short to make them tidy.

Are my able to print these parts out in PETG?

Sure. Use a bit more of infill since PETG is more flexible than ABS.

Are there any adjustments i need to in the firmware or does this work as normal when i turn it on?

The printer works with original firmware. Only XYZ calibration is a bit tricky, new frame is a bit higher than original one. Nothing complicated, just keep X axis leveled and the nozzle at initial calibration height above the heatbed (208mm) when asked for moving the extruder all way up. And be ready to immediately reset the printer if anything goes wrong during selftest and calibration.

Mar 6, 2017 - Modified Mar 7, 2017
SchoolyBach - in reply to davtr

Thank You very much for the reply, the 609ZZ bearing are for top of z axis? I have read that it is best to keep the top of the rods free for alignment? what did you use instead of T-Nuts? and as for XYZ calibration does it need to be exact 208mm? or will probe compensate?
and also for the PSU cables what size cable did you use (AWG/gauge)?
sorry for so many questions but just want to make sure i know what I'm getting myself into.

bearing are for top of z axis? I have read that it is best to keep the top of the rods free for alignment?

I like my solution more. If the printer is assembled well and lead screws are not defective (bended), it works great and looks better.

what did you use instead of T-Nuts?

I used these: https://www.aliexpress.com/item/50pcs-304-Stainless-Steel-Hex-Flange-Nuts-M6-Antiskid-Nut-Metric-Thread-DIN6923/32712563165.html just because I got a lot of them. ;-) But T-nuts are way better, of course.

as for XYZ calibration does it need to be exact 208mm? or will probe compensate?

You will have to move extruder (X-axis) all way up as first step of calibration process. On original MK2 this ensures X-axis is level and in exactly defined height. Calibration process then moves X-axis down and begins searching for calibration points to find out printer geometry. If you move it too high, it won't be able to track the calibration point. If you move it too low, it will crash into heatbed. There is some safe range, I guess 206-210mm.

for the PSU cables what size cable did you use (AWG/gauge)?

The same as original one. ;-) I don't know. It should be able to carry currents of about 25A, so you should be ok with 12AWG.

Mar 7, 2017 - Modified Mar 7, 2017
SchoolyBach - in reply to davtr

Thank you for answering, just to mention this is a brilliant design and I hope to get it done soon.

12AWG might be quite thick.
Heatbed is rated 15A, hotend not more than 5A, so total of 25A is peak power which is quite rare situation. I think you should be ok with 14AWG or maybe even 16AWG. Better check original cables before buying new ones.

Okay i think i will go for 14AWG, one other thing is what length screws do i need for M6/M3/M2.5 screws do i need and roughly how many of each? Sorry for so many questions.

Mar 7, 2017 - Modified Mar 7, 2017
davtr - in reply to SchoolyBach

Well that's quite tough question. :-) Unfortunately I didn't build up any BOM during building phase of the frame so I haven't got any record of consumed screws. Most of M6 were M6x6 and M6x8. Too long screws will collide with 3030 extrusions. I made myself supplies of M6x6, M6x8, M6x10 and M6x12 (50 pcs each) and used them as needed.
M3 - I really don't know. Some for Y bearing housings, some for Y-belt-holder (original ones are too short), one longer for Y-idler pulley, maybe original fits ok. I don't remember any more M3. Edit: of course - Rambo case and PSU need some M3 too. And I remember I reused some M3 from original kit frame.
M2.5 are used only as adjustment screws on Y-idler and Y-belt-holder, I think they are M2.5x15

Mar 7, 2017 - Modified Mar 7, 2017
SchoolyBach - in reply to davtr

Thanks, what size M3?

Comments deleted.

Im seeing some confusing information in here regarding rod lengths. To confirm, this modification uses the stock rods, except for the Z rods are longer (360mm)?

Y rods are longer (360mm), all other rods/steppers/thread screws are MK2 stock.

Love this design! Quick question for help, I can't mirror the z axis parts for the opposite side in slic3r. Can you provide this STL, please!!!

Thank you!

Mar 5, 2017 - Modified Mar 5, 2017
davtr - in reply to ash_melle

I'm not at the right computer at the moment. What exactly doesn't work for you? Mirroring (flipping) process is quite simple in Slic3r. Just add the model, right click on it, choose Mirror->Mirror by X (or Y) and done.

what about using 2020 extrusions

Hey, thanks for the nice mod... can anyone advice a cheap AL extrusion online reseller in Europe with cut to length capability ?

Feb 23, 2017 - Modified Feb 23, 2017
davtr - in reply to Gilles31

Did you read all the comments? Did you try http://www.aluminium-profile.co.uk/acatalog/30x30-Aluminium-Profile-KJN990720.html mentioned below? I hope that eshop shoud be OK. Unfortunately, I buy at local shops who don't sell outside CZ.

I thought i had but on my phone screen it's easy to miss one.
Thanks, that's great!


Really basic question: How can you ensure that the nuts and bolts for the frame will tighten? I'm about to order parts and can't get it out of my head the idea of nuts just spinning endlessly inside the profile and then the whole frame being loose...

The profile I will be using is this: http://uk.rs-online.com/web/p/tubing-struts/3899796/

I see from the Rebeli-x project they used the m6 with a flange which I believe has a diameter of 14.2mm. This being a circular flange, will it not just spin inside the profile when I try to tighten it? I was considering square nuts as an alternative to avoid this.

Feb 20, 2017 - Modified Feb 20, 2017
davtr - in reply to alexbolger

Nuts with flange actually work quite well. :-)
Anyway, I have modified some parts recently to make them usable with sliding T-nuts. Consider using these. https://www.aliexpress.com/item/10PCS-M6-Hammer-Nut-Aluminum-Connector-T-Fastener-Sliding-Nut-Nickel-Plated-Carbon-Steel-for-3030/32625863352.html

Thanks for the reply. Are you able to tell me a more precise number of bolts and lengths required? I'm converting from the original i3 mk2 so any screws that came with that I will still have.

So far I've got:
16 m6x14mm for the corner couplers top and bottom
20 m6x14mm for the flat L brackets
8 m6x14mm for the y-rod holders
8 m6x14mm for the top of z axis
4 m3x14mm for the feet on bottom corner couplers
6 m3x14mm for the y bearing housings

Ok for anyone else pulling their hair because the manual says 45mm on page 17 for the y rod holders, it is actually 39mm. The manual is for version 1 and the version 2 rod holders are longer.

Is there any way to just buy the metal pieces to upgrade my printer?

Feb 15, 2017 - Modified Feb 15, 2017

I have copy of prusa i3. Hictop 3dp11 and I got some extra parts like 1.3RAMPS etc.
Could I use the parts and this frame etc. and get it to work?
basically just buy same parts as for origanl hictop but use sturdier frame?
Tho it has smaller table, only 270x220, is that problem at all actually?

I know these are stupid questions but I just want to confirm them before starting to order stuff.
What stepper motors would you guys recommend?

270x220 is actually a bit larger than original i3 MK2 heatbed, but it should fit into the frame since there is still some space with MK2 heatbed mounted. But I'm not sure you will be able to use all area of heatbed for printing without some modifications to X-axis or extruder.

Forgive my pestering but I want to use stock y-rods. I'm not at home, does anyone know the length of these so I can reduce the y-extrusion length?

Feb 15, 2017 - Modified Feb 15, 2017
davtr - in reply to lachycharts

You will most likely not be able to make the printer work with shortened Y rods (without further modifications) since MK2 needs to calibrate Z before print and it needs full movement range in X/Y for that calibration.

Ahh, I see, thanks for replying :) Is this full range of motion not achieve with the stock rods and this upgrade because of the thicker frame or longer bearings or something else I am missing?

Longer bearings first of all. If you make the LM8UU holders shorter, there could be also collision between y-carriage and the frame or y-axis printed parts. I can't tell exactly what could go wrong, I never tried that.

No worries, mate. I've bought some 400mm rods and will cut them down. Thanks for a solid mod :)

Am I correct in assuming this mod does not improve print quality or at least not significantly enough to be worth doing for that reason?

Feb 13, 2017 - Modified Feb 13, 2017
MartinCooper - in reply to davtr

Thank you davtr. So then what benefit would this mod serve?

It's been told in thing details summary. ;-) In short - no more fiddling with frame geometry when trying to achieve perfect XYZ calibration. No more lost calibrations after moving the printer from one place to another.

Sorry. Didn't read it properly. Cheers!

I can attest to that, I've recently finished building this. Calibration came back as perpendicular on the first try, and while I've not seen any quality improvement, I have had two benefits: my bed seems to now be perfectly flat and I can easily up the print speed to 60mm/s (PLA) without it shaking itself to death.

Oh nice. Ok, maybe worthwhile after all then.

Comments deleted.
Feb 12, 2017 - Modified Feb 12, 2017
wodain - in reply to Jason3030

I am not sure if this is what you are looking for, but here is a link to a bill of materials for the Rebelix/Mk2 printer with links to suppliers. Hope it helps.


yeah.. we didn't publicly release that yet because we are still testing..

Is there a proper list now?


Brilliant rework of the frame. I Havent got my Mk2 yet, will probably be here in SA on March 15th but this is the first thing I am going to do. The design looks really good and much more sturdy than the original.

I have a couple of questions though. Is the PSU attached to the z-axis frame and just resting on the bottom frame, or is it attached to the bottom frame too? Also, did you assemble the printed and print the part for the new frame and then disassemble the old one and reassemble the new one, or are those parts printed on a different printer? I am also going to do some research to see if its possible to have the T-slot anodized black.

great work once again.

Is the PSU attached to the z-axis frame and just resting on the bottom frame, or is it attached to the bottom frame too?

PSU is attached to Z frame only.

are those parts printed on a different printer?

No. I bought MK2, because my old printer was unreliable, obsolete and not worth any upgrades. I assembled and calibrated MK2, disassembled old printer to bare frame only, then I started to design new printed parts. I tried hard to design it the way it needed very little effort to switch components from one frame to the other one. If you are handy enough and got all parts ready, moving X/Z axis to new frame takes only about half an hour to the point where it is able to work again.

This should work since the most crucial parts to get are the Heated Bed and the probe. Rambo can be bought seperatly or even changed for any other board that drives marlin. PSU, LCD etc are standard parts which u can get everywhere.

I will go this way since I dont see the point spending 700€ on a printer I completely want to rework.

You will still miss a lot of parts. RAMBo mini, PSU, LCD, y-carriage and maybe others. If you're not experienced 3D printer builder, I rather recommend full kit instead of upgrade.

Is possible to adapt this upgrade to this printer?


Folgertech Prusa i3 2020 Y-Axis Upgrade (Openbuilds V-Slot Rail System)

I am not sure why you would adapt this to DAVTR's work. At this point, you would be upscaling all (or most) of your 2020 to 3030. You would have a "non-Folgertech Prusa I3 3030", not a MK2-X. I am thinking that they use the v-slot for their linear rails and I think that only comes in the 2020 sizes. You could keep the X and Y as linear rails as v-slot. The Z could be the same configuration as DAVTR's MK2-X (you would still need to adjust the x-carriage to accept v-slot instead of rods). Interesting remix of the two. A lot of design work for you to go through.

Most likely, yes, it is possible. You will first need the frame assembled to be able to modify and fine-tune printed parts for that type of frame. Good luck.

My doubt is about the size the frame: one is 3030, the other is 2020. So, is possible to adapt the parts?

I'm guite sure it is possible, but I agree with mikewrobel - I really can't see a reason why to do that.

Thank a lot for your help!
I will start to mount this printer from the scratch. Is very difficult to find the material?

I have a question - It looks like the bed is lower than the Z motor mounts. Is there clearance for the PINDA probe when the extruder is at the far right of the bed?

Don't worry, there's a few milimeters gap.:-)

Great - I've already printed the parts and I've not run out of material :)

:-) Good luck.

davtr: I found a couple of issues that impacted me with your files. The z-axis-top and z-axis-bottom did not allow the sliding T-Nut (one T-nut on one and two T-nuts on the other) to pull in tight. The plastic on the back that is made to go into the slot to help with alignment does not allow the sliding T-Nut, also with its guide, to pull tightly against the 3030. I removed the part from the 3030, tightened it lightly, drew a line with a Sharpie, and used a Demel and file to remove the offending plastic. Also, the carriages on the left and right that hold the rods for the x axis... Mine were very tight, to the point we could not get one rod seated (possibly caught and edge and rolled some plastic as I was pressing the rods in), have since broken a piece because of pounding, and will need to cut the plastic off to recover the rods. You might want to consider some small 'observation' holes along the path where the rods seat. Maybe I could see in each hole, how much progress I am making. If not visually, maybe with a stick pin or sewing needle. Other than that, an awesome set of parts!!! Very well built.

The z-axis-top and z-axis-bottom did not allow the sliding T-Nut (one T-nut on one and two T-nuts on the other) to pull in tight.

Hi Mike,

I finally found out what did you mean with your comment. :-) I couldn't realise your problem since I don't use T-nuts. One friendly builder explained it to me, so I redesigned some parts to make them work with T-nuts. Thanks for pointing it out. I'm sorry I didn't understand it at first reading.

Jan 30, 2017 - Modified Jan 30, 2017
davtr - in reply to mikewrobel

The z-axis-top and z-axis-bottom did not allow the sliding T-Nut (one T-nut on one and two T-nuts on the other) to pull in tight. The plastic on the back that is made to go into the slot to help with alignment does not allow the sliding T-Nut, also with its guide, to pull tightly against the 3030.

Hi, Mike.
Those parts heavily depend (rely) on accuracy of printer they are made on. Alignment plastic is 2mm thick and it should correspond with thickness of AL profile casing sheet thickness. I've never got into trouble with sliding T-nuts behind those plastic parts.
On the other hand, I never tried to slide T-nut behind z-axis-top part while other T-nut was already fully tightened. I usually try to set the screws in T-nuts, check alignment of the frame and only then tighten both T-nuts.
Regarding x-end parts, I haven't designed them. Again, it is the matter of accuracy and calibration of your printer. Rods should be able to slide into holes with reasonable amount of effort. However there should be no play at all. By the way, I was forced to use rubber hammer to get rods into x-end parts provided in Original i3 MK2 kit from PR. ;-) Fortunately I did not brake anything.
Anyway, you can see the progress by looking against strong light source (sun, headlamp) unless you printed from black filament. In case of bad troubles with sliding rods into X-end holes, you can use 8mm drill (with a bit of caution) to make holes accurate and clean.

Dave, x-end parts were the correct size. I needed to 1) clean out some debris from the holes, and 2) taper the end of my rods with a little belt sander. I use parallel clamps in my woodworking. I took two of them and gradually squeezed the part together. SOOOO much better than pounding and breaking that protrusion off. Also, I stuck an unsharpened pencil into the hole, marked the distance with a Sharpie, then transferred the mark to the rod. Now I knew I was seated completely.

Thanks Dave. I had intended to send you a picture, but I got put on 12 hour shifts a work until today, so I hadn't fiddled with the printer in a bit. I am remembering another part with the same problem... I will have to take a look, but it will be obvious to you that any part with the same alignment tab will have the same problem. Also, those aluminum profile covers (with and without the hole) don't fit on the 8020 brand 3030 that I purchased through Fastenal. I have a square channel that runs the length of the extrusion in each of the corners. I have to shave off the tips of the alignment plastic to make it fit. I can send measurements, if you want to create an option or just not have those tips on your piece all together. I will go see if I can PM you a photo.

Could you tell me the print speed you can run maintaining a good to okay quality

I usually print at 40-60mm/s. I think it could go up to 80mm/s with no significant impact on quality of output. But I never tested it this way.

do you happen to have a benchy from when you used the original frame ? could you compare your best benchy to the best of the original frame?

Print quality is almost the same (I can't see difference). This project targets mostly on accurate and easy assembly and calibration.

could you document the exact lenght s of alu extrusions you have used please? also do you use openbuild extrusions ?

Jan 29, 2017 - Modified Jan 29, 2017
davtr - in reply to rianvelders

Lenghts of 3030 profiles are

X: 360mm (3x)
Y: 320mm (2x)
Z: 330mm (2x)

I don't use openbuild profiles, but they should fit if their gap is 8mm wide and casing sheet thickness is 2mm.

Jan 24, 2017 - Modified Jan 24, 2017

would this allow us to increase the max print height of the prusa i3 mk2 ?
side ways carriages delta style could be designed for the Z axis and by doing that we can define the lenght of the z axis ourselfves ?

Of course, it is actually very easy to redefine Z axis length. Just make the frame taller, get longer Z smooth rods, longer Z lead screws, probably longer cables to extruder, and redefine max Z height in firmware.
But you will most likely be unable to print ABS that high since bed heating is very ineffective in higher Z unless the printer is in enclosed environment.

Jan 21, 2017 - Modified Jan 21, 2017

I am in the process of building one. During the build I didn't like the spool holder so I remixed thing 1832235 to suit my needs. hope you guys will find it helpful .

MK2-X Spool holder

i have made an corner coupler for the 30*30mm profile


Alu profile 30*30mm 8mm nut corner coupler

Are you using these in addition to the current MK2-X corner parts or instead of the MK2-X corner parts.

Looks good. Is it strong enough?

I am not using an PRUSA MK2 bed, but rather looking at 200x300 or 300x300. Is there simple math to calculate the length of the 3030 (x and y) and the rods (x and y)?

Just correspondingly enlarge particular dimension. Current frame allows use of 250x200 heatbed. If you want to use 300x200, add 50 to X axis. If you want to use 300x300, add 50 to X axis and 100 to Y axis. Don't forget to get longer smooth rods.
Also consider conversion to 24V heatbed, that large bed may drag too much current to be fed by RAMBo at 12V. Limit is 15A.

Thanks Davtr. I already have a 2nd power supply for just that reason. I was going to power the heat bed separately.

HeatBedX + 50 BY HeatBedY+100

I think my Smooth Y Rods go to the middle of each 3030 T-slot, so that is easy.

Do you have a table that you refer to on the smooth rod diameter? That is, how much deflection you allow versus the deflection of each diameter smooth rod. I just saw an 18in X 18in (457mm X 457mm) on ebay and have a need to print (over and over) a 16-1/4 wide thing If it prints well, I don't have to print in two pieces and solvent weld (ABS) or epoxy (PLA) the parts together. These parts are perimeters for my bee hive boxes, so not a lot of filament (maybe 10-15 hour prints), but I need a large area to fit the shape.

Do you have a table that you refer to on the smooth rod diameter?

No I don't. It was only a estimate based on my experience so far.

I'm planning to build this, (second DIY printer)
thinking I would add a 200x300 or 300x300 print bed....
so i'm looking for input if the 8mm rods would still be fine or would i need to go up to something thicker??

MK2 uses 250x200, I think 8mm rods should be fine with 300x200. I would use 10mm rods with 300x300.

Is there any place in the USA that I can find affordable M6 T-Nuts that are compatible with 3030 extrusion with an 8mm slot? I am ordering from China, but that slow boat is going to make me miss my build date. I need about 120 (so 150 to 200).


I started to build two MK2-X, printed out your parts and noticed that your parts won't fit in my profile. Could you anyhow send me those part files, so i could modify them, or if you could change dimensions to correct ones for me. In my profiles the profile gap is 6.2mm, or atleast webpage where i ordered my profiles says it's 6.2mm. Can't get one profile piece in my hands atm to measure with my unaccurate caliber. I think it would be easier if i could access to original part files. I would appreciate it A LOT. Thank you :)

Ps. Nice work !

On the RebeliX RepRap site ( http://reprap4u.cz/category/navody/ ), I located a BOM (actually, a list of materials), but it was in Czech. Click the link for "RebeliX X2". I converted all the words from Czech to English the best I could (thank you Google). It is near complete but not yet verified with an actual build. I am avoiding actually publishing it until I do my build over the next few weeks. Click my Avatar (the ICON to the left of this text) and private message me your email address and I will send you what I have so far.

I'm sorry I'm afraid I won't be able to help you. As mikewrobel already said in his post, it will take quite a lot of work to redesign parts to fit another type of profile. I recommend either buy the right type of profiles or design your own versions of printed parts from scratch. It's not only about gap width.

Well, i modified those STL files and now im able to print parts what fits. Thank you anyways :)

What was your fix? Scalling? Were you just able to modify the SCAD files pretty easily?

I did seek tutorials for editing stl and was able to convert it fully to solidworks with help of FreeCAD. After it, i did cut those profile fittings to correct size and adjusted washer holes to match with my washers. Pretty easy, didn't take much time.

Per the 'Thing Details' tab, if you scroll down, you will see that it is made for 8mm, not 6.2mm. That said, you can find the SCAD files on GitHub ( https://github.com/RepRap4U/RebeliX ). If you know, or can learn OpenSCAD, you should be able to modify these files. The 6.2mm might also change your bolt sizes and t-nuts too. You should check before you buy too much hardware.

Jan 8, 2017 - Modified Jan 8, 2017
f4ilu2e - in reply to mikewrobel

Whole project page is kinda awfull, no full info BOM etc. have to gather info from different projects and in czech, no thankyou. Ill figure problems by my own and in the end i can design totally own pieces. :) - Well humans can do mistakes, especially when manual is super bad :) ( no offence davtr, but you know it could be a bit better ;) )

Hi f4ilu2e, I did the same mistake as you did when ordering the profiles. I also ordered 30x30 with 6mm slot width. I'm going to convert the open scad files from GIThub to STEP files for the sake of changing them in Fusion 360 to fit to my profiles. As you've obviously gone through this already, did you face any issues where you had to change more than the slot dimensions? Would be great if you could give me some feedback.
many thanks in advance.

Hi Golkun,

I didin't need to do any else modification to parts, than make sure it will fit in my profile. For me it was to cut down to 6.2mm width on profile bump. Plus i found out when you do it for 6.2mm width and you use M6, so you have to cut a piece around a hole, because printer is not able to print 0.2mm wallthickness. But since your profile is exact 6mm, you already will cut those walls what i got around holes. Does an M6 bolt fit in your profile? :o

Hi f4ilu2e,
thank you for your response. Actually my profile t-slot is also 6.2mm wide.So everything should be quite the same as with your construction.

Feb 12, 2017 - Modified Feb 12, 2017
f4ilu2e - in reply to Golkun

Hi Golkun,

Unfortunatelly i wrote yesterday within rush. I didn't remember to tell that i had to modify firmware also a bit. There is differencies in height etc. For me my brother did this (we both upgraded), but as far i understood it wasn't that difficult. I hope your upgrade goes as well as mine did. :)

EDIT: What i wrote above, prolly wont apply to you, as i changed y-carriage to alumium one and it gave a bit more printing height, not sure tough did something else change.

Jan 8, 2017 - Modified Jan 8, 2017

Are the Igus parts mandatory? I see a 'y-bearing-housing' in this Thingi and a 'y-bearing-housing-RUMP-01-08' in the Igus Thingi (1898131). I do NOT see any 'x-carriage...', 'x-end-idler...', or 'x-end-motor...' in this Thingi, only in the Igus Thingi.

No, igus parts are not mandatory. This project is designed as rework of Original i3 MK2. You are supposed to take parts from your original MK2 printer bought from Prusa Research. Only modified parts or new parts necessary to build the frame are included in this project.
If you want to build the printer from scratch, you will have to search Prusa github repository for rest of the printed parts.

Igus bearings RJMP-01-08 have 16mm diameter, which is larger than commonly used LM8UU. That's why I published modified parts for that bearings for people who would want to test them.

Thank you, Dave. I missed that in my reading. I will find the MK2 parts and sort that out. I am very impressed with the quality of your parts and how you lay them out so they work with gravity. I do want to try the Igus bearings, but want to get the basic printer together first so that I can see what happens with the Igus. I have seen a couple of builds online where users abandon the Igus bearings. I am not sure if some people get a bad batch or they just don't implement them right (possibly making decisions about lubricants that are faulty). As an engineer, I actually want to understand the difference and then choose what is appropriate for me.

Jan 9, 2017 - Modified Jan 9, 2017
davtr - in reply to mikewrobel

Igus bearings work well if they're properly mounted. The problem of MK2 is that bed bearings and X-carriage bearings are mounted using zip ties. If you make them too tight, the bearings get too squeezed on smooth rods and stop moving freely.
The problem with bed bearings is solved by Y-bearing-holder (it prevents squeezing of bearings). X-carriage bearings should be tighten little by little until there is no play on smooth rods, but not more. Then they work well. I'm quite satisfied with them. No lubrication needed. I can see no wear after 2 months of printing.

Can someone please confirm the length of Y and Z axis smooth rods? Y rods look like 360mm to me, but what about Z - I remember seeing a comment somewhere that you can't reuse the stock Prusa ones and they're 10mm short. Just want a second opinion from someone who has build this mod before I go ahead and cut my smooth rods. Thanks!

My Original MK2 has Z smooth rods 320mm long as well as Z lead screws (measured from stepper body).

Sorry for bad english. For some models of LCD printed body?

You don't need any new models of LCD cover. Use original LCD cover for i3 MK2 and print only new LCD supports provided here.

Is it really a good idea to have 608 bearings in the top z parts? If your rods aren't perfectly straight this could potentially add a lot of z-wobble, as it seems to be doing for me. What's your take?

I have built 6 printers based on this design with no Z-wobble at all. Maybe I am just lucky? :-)

I'm just asking because I too have built a machine from this design and I'm having issues with z-wobble. I'll remove the bearings and try some more.

You can see my printer here: https://goo.gl/photos/NJqocAtP5zsELCpp7

I saw that you have mounted two rear reinforcements made with threaded rods mounted inclined.
can you share the two plastic supports please?
thank you

No, it is not a good idea. There is a reason why the Z-screw end is floating free in the original design.

If you have crooked lead screws.

That is what the 8mm rods are for. They align the carriage. The design expects the lead screws to be crooked (and it expects you not to be able to align four lines so there is no binding)

I never use crooked lead screws on 3D printer, it affects output quality even with floating ends.

Where can I find the measurements for how far to position the XY extrusions from the back of the base etc?

Please explain "XY extrusions".

Have you noticed any significant increase in print quality/accuracy with the new frame and upgrades like the longer linear bearings?

Dec 8, 2016 - Modified Dec 8, 2016
davtr - in reply to Graylyons

Please read discussion starting at Oct 12, 2016 comment by eVenom

hi,can you share a full set plastic for profile 2020? i have a lot of profile 2020 and i want use this,thank you

hi Johltzar. i have edited the stls so they work with 20x20 profiles. But they are still not sooooo pretty. have to make some changes but after that i will post my mix prusa here as Remix. Have a great weekend :)

great!!! tnx :D

Sorry, I haven't designed it for 2020 so I can't provide any models for that type of profile. You'll have to design it yourself.

what kind of version of slider: http://www.thingiverse.com/thing:1103976 do i need for this build? pls help

Smooth X-axis for Prusa i3 with Leadscrews

thank you so much :)

whould you maybe also tell me where can i get the Design for the Baseplate(under the Heatbed) / Y Axis?

thank you :)

Universal Y Carriage Plate for Prusa i3, Rebel and Rebelix 3D Printer
by stanoba
Nov 27, 2016 - Modified Nov 27, 2016
Gregorio_mix - in reply to venturebit

Nie jestem pewien o co chodzi, czy mówisz o "y-belt-holder"?

Talking about this: http://i.ebayimg.com/00/s/ODI3WDEwMDA=/z/3lIAAOSwrklVLxbQ/$_1.JPG

That should be cut from piece of metal sheet. I really doubt it is available as printable part, it should by really tough and solid.

are you sure? friend of mine told me that the 22mm version should work. did you print those together?

I don't know, you will have to find out yourself. This project is designed to use as much of original MK2 as possible. Take whole X and Z axis assembly of MK2 as-is and mount it into new frame using parts mentioned here. It will fit. If you want to use other parts, of course you can and it will most likely work well, but you will have to investigate.

Nov 26, 2016 - Modified Nov 27, 2016
venturebit - in reply to davtr

Thanks davtr :)
The 17mm version will fitt.
Right now I'm building the printer with 20x20 profiles. I have all parts so far modded for 20x20mm profile and m4 screws.
really like your build.

Hi venturebit, are you going to make available your parts for 20x20? Cheers

hi Sat5. Sure but they are still not sooooo pretty. have to make some changes but after that i will post my mix prusa here as Remix. Have a great weekend :)

I measured center-center distance of Y-axis smooth rod and Z-axis threaded rod, it is 17mm.
Distance between left and right smooth rods is 362mm (center to center).

can you measure the distance between the two vertical smooth rods? i am having some binding issue i think mine are too far apart :(

It is mentioned just one post above - 362mm

sorry! i guess i meant the ones under the bed.. the two rods there

Y-rods distance is exactly 170mm (center to center).

thank you so much :)

whould you also tell me where can i get the Design for the Baseplate(under the Heatbed) / Y Axis?

thank you :)

do you have any links for the X/Z axis which u use?


What do you mean by "X/Z axis"? The frame?

Hi, I´m working on a bigger version (300*300 heatbed), so the frame is bigger than yours (X and Y) Z is the same size. My actual printer is a P3Steel with threaded rod on Z axis and this one will have lead screw as yours. My question is if was so hard to calibrate Z axis using lead screw?
BTW great job with the printer and pieces. Thanks.

Nov 19, 2016 - Modified Nov 19, 2016
davtr - in reply to 3D_JumpingJack

There is nothing about Z axis calibration since the pitch of lead screw is well known as well as steps/rev parameter of stepper motor. You simply calculate steps/mm for Marlin and you're done.
For MK2 with Tr8x8 lead screw and 3200 steps/rev Nema17 motor it is 400 steps/mm for Z axis. Exactly, no further calibration.

Thank you, I was doing a checklist with things I could have doubt and this was one. Now it´s solved, thanks.

Hi I'm working on a similar design with some 45 45 profile off cuts i got from work. Is the distance between the Y idler and Y motor important for the calibration as the lengths i have are a little longer? cheers

No, that distance is not important. The most important is the geometry of all frame and positions of X and Y endstops, so the software can easily find each calibration point.

Ok thanks :)

just two things i wanted to point out in case somebody else missed it (it's buried in the comments for some reason)

you need 330mm for the vertical, the rebelix uses 320mm

i also had a lot of clearance issues with the x ends if i used the 370mm rods, i ended up going with 360mm rods (same as the y axis)

Thanks! Once I did that, calibration went smooth. Love this setup.

I just finish building this. I'm having problems with the calibration. The Z sits about 20mm higher than before. Bed is now much lower (by design of the 3030 material). How do I compensate for it? Z is too high for it to pick up the calibration points.

When calibration routine asks for moving x-carriage all way up, you should move it a bit lower. On MK2, x-carriage is moved all way up to make it aligned horizontally with Z frame. Knowing this, you should move x-carriage up approximately to the height where upper edge of x-end printed parts meets bottom edge of Z frame upper part. Then make X steel rods aligned (parallel) with Z frame (rotate Z lead screws by hand). Then you are done with alignment and calibration routine can continue.

I was thinking about creating some printed alignment helpers to make calibration easier, but in the end I didn't it since they were not needed any more, I did calibration only once and the printer works great since then.

Feb 19, 2017 - Modified Feb 19, 2017
EsskaaP - in reply to davtr

I really would like the calibration helpers, or even better a z top that has them build in. I want my remodel to exactly have the same funtionality as the original. If you can't provide that, do you at least have the exact amount of mm that the bed is lower than in the original? I would really appreciate that!

I understand, but I'm afraid I can't help you at the moment. I didn't write down original relative positions. I can provide an image of position of x-carriage relative to top Z frame, which is needed for successful calibration (after the printer finishes current job).

Feb 19, 2017 - Modified Feb 19, 2017
EsskaaP - in reply to davtr

That is the easiest to figure out. I measured exactly 29cm from the top of the bed, to the top of the carriage when it touches the top bracket. That is for the original Prusa i3 MK2.

I don't want to push, but did you had any chance to look into it? The current measurements would certainly help. From the top of the bed to the top of the x-idler part, when it touches the z-top.

The nozzle should be 208mm above the bed for successful calibration. There is some "range of success", I think anything between 206 and 210mm should work, but didn't try it.

Thank you for your effort, could you measure again from the top of the bed to the top of the x-idler?

Well, the printer is doing another job at the moment. :-D It will be busy for next 10 hours. But you should be able to determine that yourself. Just move the extruder so the nozzle is 208mm above the bed and measure desired lengths.

I would if i could, i want to design the new parts before disassembling my prusa i3. Cause otherwise i can not print parts anymore. So i wait the 10 hours.

What parts? You don't need any other parts (except those listed here) to get the printer working.

The new Z top or calibration parts. You might be ok with calibration by hand, i want it to be exactly like the original Prusa i3 MK2.

Feb 24, 2017 - Modified Feb 24, 2017
davtr - in reply to EsskaaP

Well, then maybe you should just stay on the original design. ;-)

I can't provide dimensions measured on original MK2 since I no longer have any MK2 in original frame. Even if I get required numbers now, they will be measured on reworked frame, so they won't be exactly the same as on original frame. I don't care about exact original dimensions, the printer works well and doesn't complain about anything.

BTW why don't you just measure it yourself on your own MK2 frame? You'll get the exact numbers you want.

Edit: on my reworked MK2-X it is 290mm, but I'm pretty sure this information is worthless for you.

You don't get it. I don't need measurements of the original, cause obviously i do have one. It seems like you don't understand me. It does not matter anymore, i will do it myself and then publish the needed parts. Thank you for your time. :)

I don't need measurements of the original, cause obviously i do have one.

Well, you said "i want it to be exactly like the original Prusa i3 MK2", that's why I thought you needed measurements of the original. Never mind, good luck.

Do you have aluminum extrusion length? BOM using metal parts?

Sorry, I've got no BOM at the moment. You can find out all required information in RebeliX assembly guide, the link is in Thing Info page.

This looks awesome. Any chance I could see this in action somewhere? Prague or Brno would be nice. Thanks

Ostrava, sorry. :-)

I got some aluminium extrusions cut yesterday and already started assembling the frame! So far so good - just one clarification. The print instructions don't mention the number of corner/bottom corner couplers. You'll need to print rebelix-corner-coupler twice (a single model has two pieces), and for the other ones, the manual says 10, but I think they should only be six.

Nov 5, 2016 - Modified Nov 5, 2016
davtr - in reply to Mavrodinov

Yes, you need rebelix-corner-coupler-bottom twice (bottom couplers contain pads for optional rubber dampeners) and rebelix-corner-coupler 6 times - 4 for top side of XY frame and 2 for back side of Z frame.
Whole set of couplers should fit to one 200x200mm print bed area to be printed at once.

I recommend to increase infill for all couplers up to 50%

Oct 22, 2016 - Modified Oct 23, 2016

Cześć, wstaw proszę prawe mocowanie silnika osi Z i lewe górne prowadnicy osi Z.

Now I understand, you are missing z-axis-top and z-axis-bottom parts for opposite side.
You can get parts for both sides yourself very easily. Open your favourite slicer, load z-axis part, load the same part again (you will get two identical parts in slicer) and apply "mirror along X axis" to one of them. Arrange and print both at one time.

Dzięki, nigdy nie używałem tej opcji, a masz link na to piękne pudełko do lcd.

LCD cover come with Prusa i3 MK2 kit, I never printed it myself. It should be available from public github repository, look here: https://github.com/prusa3d/Orignal-Prusa-i3/tree/MK2/Printed-Parts/stl
I only reworked LCD_SupportA.stl and LCD_SupportB.stl to fit into my new frame.

Comments deleted.

Thanks for the design... can you share the BOM, i am trying to figure out the length of the extrusion and screws to get


I'm sorry I got no detailed BOM. Some information can be found in original RebeliX assembly guide linked from my conversion instructions. If you are asking for some particular lenghts, please be more specific so I can try to put some more detailed answers.

I figured out most of the info

for the vertical pieces, the rebel ix manual suggest 11,5 cm from the end of the bottom from to the start of the vertical

did you follow that and it worked out ok? just wanted to make sure


Yes, 115mm is correct distance and it works great. It gets the nozzle almost to the exact center of Y-plane, which is essential to keep all area of bed perfectly reachable.

Did you see any differences in print quality? Can you post pictures of prints before and after?

Print quality is as good as with original MK2.

Would like to see post pictures as well. I think your design should allow a better print quality as it looks stable and sturdy. My original MK2 is shaking, especially the frame.
Your design attempt must result in reducing the influence of vibrations. Do not you see any improvements, davtr?

Allright, I'll try to post a picture documenting print quality of reworked printer as soon as I print something, but I'm afraid I got no picture of print quality of original assembly. There are only few photos of jet engine printed of this Thingiverse model http://www.thingiverse.com/thing:1327093 posted on Prusa3D forum:
I hope it is accessible for public.

But actually, as far as I can judge, the print quality is basically the same. There are no significant differences. Completely different is how easily can anyone get the frame to perfect shape. I was fighting with geometry of original frame for a long time. But not a single issue with geometry since rework. I only print and load new spools of filament.

3D Printable Jet Engine

We're you able to increase print speeds without issue?

The purpose of this rework wasn't increasing print speeds, so I didn't try that.

Thanks for the reply. I'd expect that if you increase the rigidity of the frame you could increase print speeds, right? At the point you are at you could probably increase print speeds a fair amount, but with a bit more effort you could probably make the print speeds vastly higher. This is the core reason I am interested in this project, I'd love to double or greater the printing speed of a prusa i3 mk2 and I assume the bigger piece of the puzzle is frame rigidity. I also imagine active cooling for the steppers, maybe a larger blower.

There is a limitation of print speeds based on hotend performance. There is discussion thread about it at prusa3d forums, unfortunately I couldn'f find it at the moment. The problem is that E3D V6 is capable of melting specified given volume of filament per second. This determines maximum print speed regardless of frame rigidity.
If you want to increase print speeds way above this limit, you will have to use E3D Volcano hotend.

Well I am sorry to say but you have absolutely no idea what you are talking about.

A more rigid frame will allow you to a) print at faster speeds which was mentioned b) increase jerk c) increase acceleration. This will all help reduce print time.

Regarding the flow rate of the nozzle, maybe you should have taken some notes from that thread and studied them because you have even less of an idea what you are talking about. The v6 maxes out around 10-13mm^3/s, depending on quite a few factors such as the filament type.

To give an example, lets say you are printing at a popular layer height of 0.2mm, and extruding a line width of 0.48mm. At 40 mm/s speed, you will be extruding only 3.84mm^3/s, well below the limit of the hotend. Above 40mm/s with the stock frame, for outer perimeters and top and bottom layers, the quality diminishes quickly. With a more rigid frame, say you wanted to double the speed and use 80mm/s, you would still be reasonably below the limit at 7.68mm^3/s.

Obviously you will increase the volumetric flow rate pretty quickly with thicker layers, but with the right filament you could still print at 80mm/s at 0.3mm layer height, but that is getting a little close to the limit.

It just bothers me to see someone act like they know what they are talking about, while providing the most vague useless and incorrect answer possible. I mean you were on the right track, but you ended up giving poor advice to waterling even though his question was backed up with his own logical opinions.

I am also surprised that someone capable of designing this, which takes quite a bit of skill, and then see them be so incredibly clueless that they can't even conclude that a more rigid frame = increase in speeds without affecting quality. It's a very simple and obvious connection.

Oh actually, considering how you constrained the top end of the lead screw, I guess you're really not so bright after all.

I have considered using the volcano, it's only 8.5mm longer. I imagine that perhaps it is viable to lengthen the Z height a fair bit, maybe a lot. I've also considered a pre-heat chamber or stage for a filament to get the filament a around 10c below it's glass transition temperature.

Ultimately, I don't really know if just making a crazy rigid frame would allow for insane print speeds, I don't know what else goes into it.

So do you think you can print faster utilizing a much more rigid frame assuming any thermal limitations are overcome?

You will still have to play a bit with motors power and acceleration settings, to avoid problems with skipped steps. It will most likely fail in current silent mode setup and maybe even in highpower setup as well. Heatbed is quite heavy so inertia forces will be rather high.

I've never used silent mode, doubt I ever would. I suspect active cooling and some heatsinks could increase the power capabilities of this setup a great deal.

I have strongly considered the moving back and forth heatbed motion, I almost didn't buy a prusa i3 mk2 because of it. Eventually I am probably going to buy or put together 3D printers either in the delta or coreXY styles.

Hello. everithing looks awesome. I just don't get one thing. With this buid is possible to ave both the z and x/y auto-calibration like the prusa i3 mk2?

Of course all calibrations are working, they get excellent results because it's very easy to assemble the frame with maximum accuracy.

Hello, very interesting concept, i have a prusa I3 box, custom, please tell me the y-bearing-housing is designed for LML8UU (long) or LM8UU (short), i can not see. Thank you

Hi, you can fit there either one LM8LUU or one LM8UU or two LM8UU in row (there will be about 3mm overlap but it doesn't matter).

I will attempt to build something similar, but have a few questions. According to the RebeliX profile sizes, the profiles used for the height would also be 32cm long. According to my calculations, this would but the total size at 360W, 380D and 380H, but your description says the height is 390cm, why is that?

Also, knowledge from my existing Prusa i3 is that is requires Z-braces to reduce oscillation that occurs with the frame. Therefore I have added an extra layer to the back of the frame. Do you find that this would be necessary? You can see my sketch here: https://www.dropbox.com/s/sm7aw0kiu12205h/Sk%C3%A4rmklipp%202016-09-21%2015.53.02.png?dl=0

Dimensions - you're right, but my Z profiles are 330mm long, thus 390mm total height. It's by historical reasons (I don't exactly remember why) and it basically doesn't matter.

About oscillations - your sketch looks interesting, but you will definitely come into big trouble mounting PSU and Rambo. There is very little space over there. Also, that perpendicular frame does not eliminate oscillations well. Diagonal braces would work much better. But there is even less space for them.
By my experience oscillations of Z frame are of no importance, they are way smaller than high frequency vibrations coming from motors and belts.

Oh, then I see, good to know! I actually updated the sketch and removed the rectangular braces. I added a bottom level where the PSU and electronics will be enclosed instead: https://www.dropbox.com/s/6p13ly11nbmju46/Sk%C3%A4rmklipp%202016-09-21%2019.18.00.png?dl=0

Also, I'm porting a custom homemade Prusa, not an MK2, so I'm using RAMPS 1.4.

I'll add diagonal braces later on as well :)

Looks interesting. I really look forward to your design, I hope it will be available for public. :-)

Yeah, it will share it for sure once I'm done. I just have another question for you. Did you assemble the bottom of the frame using only T-nuts and the plastic parts to hold it in place, or did you attach triangular brackets or something more?

I've almost decided to skip the old sketch and build the bottom using 30x60mm profiles. This would still give me room to fit all the electronics and PSU. It would also be less bulkier, requiring less profiles and less angles etc for assemble, so should be more stable.

Here's my updated sketch if you're interested: https://www.dropbox.com/s/r0ul6x4s9sdte33/Sk%C3%A4rmklipp%202016-09-25%2017.54.57.png?dl=0

Yes, bottom of the frame is assembled only using plastic corner-couplers and screws/nuts/washers. Actually Z-frame is what prevents it from twisting.

Oh, I see, so the bottom itself is not very sturdy? I was thinking I would mount using the same corner couplings, but also add some angles on the inside just to be sure. Not exactly these, but similar ones: http://g03.a.alicdn.com/kf/HTB1Uf_GIpXXXXcSXpXXq6xXFXXX3/10pcs-lot-DIY-4040-Serie-font-b-Corner-b-font-font-b-Brackets-b-font-Angle.jpg

Bottom itself is sturdy enough, but it is still only rectangular frame with no braces, so if someone used too much force, it would twist or change shape. However it is sturdy enough for 3d printing needs.

I stumped upon your project by coincidence but in process of doing the same thing as you (with the only difference of building a dual extruder). It made my day to see I´m not the only one going in this direction.
NIce job!

Hi, it's good to know there are allied souls around. :-)
Are you going to post your work on Thingiverse? I'm always open to get inspired by other's solutions.

I can post it here after I´m done building the mechanical part. But I´m mostly just remodeling parts done by Martin Neruda for Rebelix to fit my needs and basicaly the only two major differences are in attaching Z-axis to Y and the extruder (as it will be the dual one).

Aug 17, 2016 - Modified Aug 17, 2016

This looks amazing!

This seems to make it a lot easier to access all the parts of the printer for adjustments and modifications - I just finished an MK2 upgrade which seems very fiddly compared to your design.

Can you give some impressions on how your machine performs in daily use? What sets it apart from the original MK2 the most?
Since the print quality of the MK2 is already very good I suppose your design mainly aims at ease of use and modifiability?

I did a quick check of Prusa's official forums and didn't find your project there. Maybe this would be a good place to develop your machine further?

Finally: Was it worth it? for someone with an already well working MK2, would you recommend changing to your design? How long do you estimate will building it take?

Thanks so much for sharing!


I'm glad you like it. :-)

My project of course is mentioned on Prusa's official forums. In English section here: http://shop.prusa3d.com/forum/original-prusa-i3-mk2-f23/any-tips-and-tricks-on-how-to-align-the-smooth-rod-t1290-s30.html#p10646 and in Czech section here: http://shop.prusa3d.com/forum/original-prusa-i3-mk2-f22/vestavba-mk2-do-jineho-ramu-t1398.html

Regarding your questions: the output quality of redesigned printer is most likely the same as of original design. I was very satisfied with MK2, like you are. The only problem was that I was unable to adjust the frame to perfect shape. I was constantly fighting with some imperfections of geometry, and with unacceptable noice from heatbed linear bearings. I hated that.

Was it worth it? Well, I don't know exactly since I had all needed components already home as remains from previous printer, which was outdated by MK2. I had to only design some adjustments to printed parts. The conversion itself was very easy and quick, it took about 3 hours. Now, when I know what to do and how, it would take maybe 2 hours or less.

The printer in new frame is more silent, precisely set up (even self calibration says it's perfectly perpendicular), heatbed carriage goes very smoothly and has absolutely no play in any axis. Adjustments are easy and adjusting one parameter don't break other one. Adjusting anything on original frame was painful like hell.

Would I go into this conversion again? Definitely yes. I like to improve things. And I'm going to further improve this one. TODO list still isn't empty and maybe there will be some other improvements coming in my mind. :-)

I hope you'll get inspired.

Aug 18, 2016 - Modified Aug 19, 2016
tonius - in reply to davtr

Thank you very much for your reply.

When attempting to download the RebelliX guide from http://reprap4u.cz/download/712/ which you mention in your how-to, I get a timeout. Is there any other source I might try?

Best wishes

I don´t know if I am not writing too late for you, but the download link works again. There was some problem with file location if I recall right.

Oops, it looks like their website changes download links from time to time. :-/
Please go to http://reprap4u.cz/navod-na-stavbu-3d-tiskarny-rebelix/ and at the bottom of page there is download link labeled "Download Návod na sestavení 3D tiskárny RebeliX". This is it.
Anyway thanks for pointing out, I will update my conversion guide.

I really like this idea. Where is the aluminum frame sourced and cut from?

http://www.alupa.cz/hlinik/al-profil-kombi-stojka/pro-CBU0000101.html (Czech language)
Better try to find some local store. Just remember that printed parts count on dimensions of profile, it should be 30x30mm with the groove width of 8mm.

The problem with our local ALUPA profiles is that they are available just locally :/ so its almost impossible to get these elsewhere :( i based my printer on these profiles too, quite a lot ppl not building it due to this fact. otherwise, its nice. good value, easily cut to desired length...

Any 30x30 profile with 8mm groove should work, for example http://www.aluminium-profile.co.uk/acatalog/30x30-Aluminium-Profile-KJN990720.html
The only printed part strictly dependent on Alupa profiles inner shape is end profile cover, it might need minor adjustments. But it is not necessary part of the frame, its role is just cosmetic.

Oct 25, 2016 - Modified Oct 25, 2016
Otomar - in reply to davtr

I can confirm this. We use these profiles on some projects in UK.
These profiles are better than ALUPA because you can cut thread in central hole and screw it together with other profiles. Then the frame is even stronger and you don't need plastic brackets.

that's the idea i am going with, to use a beefy M8 bolt to hold the frame and extrusion brackets for the 90 degree corners