Upgrading my MK2s to be a MK2.5+

So I decided it was finally time to upgrade my printer with the 2.5 upgrade I received several months ago. I had come close a few months ago but then the R3 parts came out and I also had under-extrusion issues on the parts I had printed so I had put it off.

Here is my printer as it was:


I tend to make rather a mess of my workspace so I thought I would start with a bit of organisation to try and contain some of the chaos and reduce the chance I wouldn’t be able to find the parts I need. I prepared a number of containers to put all the parts in as I dissembled my printer, and to also put the upgraded parts in ready for reassembly. You can see all the parts I had printed for the upgrade in a box lid on the left. I printed all the parts to turn the printer gold (eSun solid gold PETG was the filament I used).


These are the parts I printed for the upgrades I planned to do:

All printed in eSun solid gold PETG except the extruder parts which were printed in the black PETG provided by Prusa for the upgrade, and the fan nozzle which was printed in Prusa Gold ABS.

First I dismantled my printer which took a few hours.


I then put the new printer together over more than a week – a few hours each day, taking it slow.

New front and back ends for the X-Y frame:IMG_5148

I regreased my bearings using the instructions from Chris Warkocki, excepting that I found it quite difficult to clean the old lithium grease out of my bearings. I used white/mineral spirits rather than IPA, and still needed to use a disposable wooden chopstick to help with cleaning it all out.

Printed replacements for the U-bolts.IMG_5164

I had to use a hacksaw to cut down a M3x40 screw to get a 15mm smooth 3mm rod as an axle for the 16T idler in the X-end idler. I used an 8mm drill bit to make the holes for the smooth rods in the X ends large enough. It took a while but I managed it in the end. I also found the slots for the square nuts a little narrow and managed to slightly break one of the holes but was able to glue it back together with super glue. After this I was careful to check the size of holes before I forced anything in. Its best to take some time to prepare the parts before you start as these parts have been designed to quite a tight for the screws and nuts and depending on your printer’s tolerances they may need some work with sandpaper or a sharp knife. The same applies to the extruder parts later on. I found the 3mm drill bit with its holder from the MK2s upgrade useful at times.


While building the extruder I managed to destroy a vital part while attempting to put a nut into bond tech idler. I put out the call to a NZ 3D printing facebook page and someone in my city printed me a new one. The 3D printing community is fantastic! I was also lucky enough to be in conversation about the build of the X-axis and the extruder with the designer Vecko Kojchevski who made me an stl with a slightly larger hole for the nylock nut which meant I didn’t ruin the part a second time. I was very lucky to have him helping me out. I also found when installing this part that I only needed a nylon washer on one side or the gear wouldn’t line up properly with the filament path. I really was a bit of a klutz putting together the extruder, even snapping off a thin fin of plastic. But eventually it all came together.

Once I had the bed on I laid a straight edge across it and found it was slightly higher in the middle so I tightened those screws and then it was pretty flat. All was complete. And then I tried the self test and the extruder could not hit the X-stop, missing it by ~5mm. Vecko to the rescue again and after a few back and forth photos and ideas, I replaced the cable holder that comes out the back of the extruder with the MK2.5 version (luckily I had printed that part out in my aborted attempt a few months ago). It still was out by a mm or two so I glued a piece of plastic (which I had broken off the X-carriage when working on it) to the extruder and finally I could run all the calibrations. Vecko has now upgraded that part so this isn’t won’t be needed any more.

I will be reprinting the extruder parts and doing a better job of putting it together this weekend. But right now I’m pretty happy to have a working printer. Thank you to all the designers who made the upgrades I have used and especially to Vecko who put up with me asking stupid questions and sending him photos saying “what do I do now?”, “what length screw / type of nut do I need here”, “Did I put this together right?”, “What idler do I need to buy?” and so on. BTW the idler I needed was “Idler bare, GT2 x 6mm wide, 16 tooth equivalent, 3mm bore” (or toothed version of the same) which I sourced from https://mecha4makers.co.nz/product/pulleys-for-gt2-belt/ but you will probably want to get from someone more local to you.

I need to redo my extruder rotation indicator as with the angled part fan it needs to be made smaller. When I do that I will put up the remixed part on my thingiverse.

Finally here is my new printer in all its glory.


Do let me know if you find this blog useful when doing your own upgrades.

Happy Printing!


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