Revised X-Axis (Prusa I3)

by vekoj Apr 15, 2019
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I printed both the revised extruder back and x-axis, however I wasn't able to get the self-test on the prusa to work. The tension seems to be different between the left and right side of the extruder. When the extruder reaches to the x-stopper on the left side, there's either too little on the left side. When I tighten the belt, the tension is too tight for the motor to pull in either left or right direction.

That sounds weird, the belt is only constrained at the X carriage so belt tension should be equal on both sides. Yes, too much tension will stall the movement of the extruder.

Can you please tell me which specific parts you printed (exact names and links would help a lot) and what is your printer setup (what extruder and frame) . Pictures of the issue will be helpful as well.

I'm Fitting Bondtech extruder upgrade for Slicer Hot ends, which Means I need to use Bondtech's X Carriage Kit, will these work with your X Axis Parts,, My Machine is the MK3s.

I haven't had the chance to check the new version of the Bondtech extruder (the mosquito variant). I am not sure if the designs here are directly compatible. I will probably have a version out soon, but in the meantime you can check Bear Upgrade version, https://github.com/gregsaun/bear_extruder_and_x_axis/tree/master/optional_parts/bondtech_x_carriage/printed_parts. It's meant for the Bear X axis but it will be compatible with the Revised X Axis as well.

Thanks for the reply I have time to get this wright I wanted to get an x axis and y that can control the tension of the belts, So I don't intend to start striping the machine until I have everything in Place, I am considering the Bear full Upgrade but tempering this with time to do rather than printing?? I will look forward to seeing your next design, where is the best place to check Hear??

I apologize but I am having problems understanding your question. My designs are published here on Thingiverse for the time being.

Hi! May I kindly know what is the difference between the two versions? Thanks a lot!

I assume you are asking about the difference between the X-idler version. Similar question was asked in the comments below. Answer copied from that comment:

"It is a design that was present in the MK2S design version of the X ends. They are used to slightly adjust the distance between the X ends, one of the reasons perhaps being slightly off spec rods. Other being that Z stepper motors cant be positioned precisely (as in CAD lets say). They should provide some counter force to the belt tension, however its debatable considering the "stock like version" (MK3) does that as well.

Warning, do not use the two screws version of the X-idler without screws. The distance is 0.5mm shorter to allow adjustment.

If you ask me, the "stock like version" of the X idler is more hassle free (less adjusting). I ended up using that one myself."

Thanks! How about the X-Motor ends? Is there a difference?

Yes there is, they are compatible with their respective printer model/version. MK2 uses mechanical end stops (switches), where the MK3 uses sensorless homing via the TMC drivers. So the MK2 version of the X-motor has mounting points for the end stop switch, while that feature is removed on the MK3 X-motor because its not needed.

If in doubt, the MK2 (or MK2.5, works for both) will do the job, even if you decide not to use mechanical end stops.

Great! Thanks for your help! Will start to print now.

What does the screw on the top and bottom that presses against the rods do? The rod seems perfectly snug and aligned so I’m confused at there purpose. Do people get shorter rods?

It is a design that was present in the MK2S design version of the X ends. They are used to slightly adjust the distance between the X ends, one of the reasons perhaps being slightly off spec rods. Other being that Z stepper motors cant be positioned precisely (as in CAD lets say). They should provide some counter force to the belt tension, however its debatable considering the "stock like version" (MK3) does that as well.

Warning, do not use the two screws version of the X-idler without screws. The distance is 0.5mm shorter to allow adjustment.

If you ask me, the "stock like version" of the X idler is more hassle free (less adjusting). I ended up using that one myself.

That makes sense. Already printed the adjustable one though :P Thanks for the feed back :)

Nice work, is it compatible with MK3S with standard extruder. Can i still use the same belt, or should i buy longer?

Greetings Kris,

It is compatible with the standard (stock) Prusa MK3S extruder, however it needs a custom X-carriage (https://www.thingiverse.com/thing:3560132). It's has only the belt path edited, the rest is kept as close to the stock (standard) as possible. Everything I just mentioned is included in the description and links are included.

About the belt length, the distance was slightly reduced from stock (few mm), so the same belt should work, depending on how much did you cut off the ends. In principle, the same belt length will work just fine, but I always recommend having spares, just in case.

X-Carriage for stock Prusa MK2.5S / MK3S Extruder (Revised X-Axis)
by vekoj

Thank you !

Can a stepper motor damper be mounted to the X-axis motor without any issues?

I haven't used one myself to say with certainty but, in terms of clearance with the frame, it should have plenty so I dont expect a problem there. There is a small indentation for the motor that might cause some issues, although a small edit should fix that easily.

I'm using the old X axis ends (http://www.thingiverse.com/thing:2957916 ) with your newer MK3S carriage (http://www.thingiverse.com/thing:3560132 ) and the belt doesn't seem perfectly parallel. Should I print these revised X ends to replace the older ones?

X-Ends and Tensioner MK3 MK2.5
by vekoj
X-Carriage for stock Prusa MK2.5S / MK3S Extruder (Revised X-Axis)
by vekoj

Yes, please do print the newer version of the X-ends.

The previous version is not compatible with the carriages designed for the Revised X-axis, it has slightly different belt path as you noticed. I apologize for the inconvenience, but it was a compromise I made so it can be directly compatible with the Bear extruder and remixes based on it (example: geared extruders), that way you can swap extruders if you wish to do so.
Besides, the design was further "polished" and optimized for FDM printing, with the added custom tensioner pucks (according to your idler size) that you can switch if you want to, without affecting anything in the system (compatibility wise), so the newer version has some added benefits compared to the previous one.

I consider the Revised X-axis to be a more unified and complete project, and as such I expect it to have a longer "shelf life" than the previous ones, meaning re-prints for compatibility sake (like in your case) shouldn't be needed if lets say a new extruder comes to the market.

No problem Veko, I appreciate the time and effort that goes into designing parts like this so having to print a new, better version every now and again is no inconvenience at all. I'm planning on doing some maintenance soon anyway (along with fitting vesconite bushings and a Bondtech extruder) so I'll add "fit new X-ends" to that list. Hopefully I've got enough Prusa Orange PETG left ;-)

So, just to clarify that I've understood this correctly, if I wanted to switch idler size all I need to print is the corresponding puck?

I'm currently using smooth 16T as all the toothed variants I've tried don't seem to last very long. The bearings in 16T toothed idlers just can't handle the required tension and end up failing very quickly. Smooth 16T don't seem to have this problem as they use larger bearings, but I'm wondering whether a toothed 20T would be a better solution.

Thanks for responding btw.

Yes, that is correct, just install the corresponding puck and you are good to go. Everything else should be directly compatible regardless of the puck used, that is, if you already have a X-carriage that is compatible with the Revised X-axis. You can even pick either version of the X-idler. Basically everything linked and posted in the Revised X-axis Thingiverse listing should be directly compatible with the rest of the system, without the need to change anything else.

About the idler (16/20 toothed/smooth). I used a toothed 16t idler for couple of months with no issues, have in mind that the tensioner allows the belt to be over tightened, which might lead to issues like you mentioned. That being said, I hate the excuse "It works for me" and truth be told, you are not the first one to mention that the 16t idlers are breaking.
I have since edited the X-idler and the tensioner to allow either 16 or 20 (toothed or smooth equivalent) idlers, so one can pick the corresponding puck according to their preference and current hardware.

The smooth equivalent isn't a bad choice per se, but I recommend using a toothed idler. I personally use the 20T 5mm bore, from E3D and I am quite satisfied with it.

Please carefully read the Thingiverse details about links to the parts used, post processing and assembly instructions. I tried to make it as detailed as possible. However, if you do have any questions, don't hesitate to ask.

Thanks for the info Veko, it all makes sense now. Currently printing the Bondtech carriage, X-Ends are next in my print queue.

I'm using smooth 16T idlers at the moment (on both axis) and even though it's running ok I'd still prefer having a toothed idler so the belt teeth have something to mesh with. I tried a couple of brands of toothed 16T and they all failed. Some took a week, others failed within a matter of hours. Tension was around the 280 mark according to the Prusa FW.

Those E3D idlers sound like they'll do the job.

Bit baffled by Bondtech extruder MK3 (+MK3S Add-on) compatibility. I tried to do this upgrade and Bondtech at the same time to a stock Mk3s. it didn't go well.. I realised the Bondtech only works with Mk3 carriage after I had disassembled everything, so had to reassemble to print a stock mk3 carrier... now the stock mk3 carriage doesn't actually work with this, the path is wrong.... and only now I notice that the Bondtech/mk3 compatibility line is a link to a carrier I should have printed. Oh man.

I also had to rework the puck so nylon nuts would fit in it, and so it remotely fits in the hole. Wasn't step files for the slack tolerance version, so had to manually get rid of the circle stuff inside the puck, then printed it at 99% and finally snugly, and nuts fit in it without me having to dremmel them down to size. Phew.

Please don't get me the wrong way, but I really don't know how else to stress that the extruders are compatible only with X-carriages provided here. It has a warning at the start of the description, and the only place the compatibility with various extruders is mentioned, has clear description and links to the carriages. Did you think those links were to the extruders themselves? I would gladly change the wording in the description to make this clearer for users, please feel free to mention your suggestions. Long story short, I am using the revised X-ends with this X-carriage (for the MK3 Bondtech Extruder) https://www.thingiverse.com/thing:3560116, and I can assure you they are compatible.

About the puck, the holes for the nylock nuts should be indeed a snug fit, to prevent the nuts falling off during assembly (insertion into the X-idler). There are also slight chamfers to make the insertion easier. So make sure to use some force to push them inside their proper position. If all else fails, I can think of few reasons why it did so. You might be over-extruding a bit; the hole that is printed on the bottom of the bed can have some elephant foot that might be causing slight problems with that particular cutout; the nylock nuts you use are different size/spec. I haven't had any complaints so far about this particular issue.
I am not sure what you meant by "manually get rid of the circle stuff inside the puck", but yes, STEP files are included so you can make the necessary edits if the need arises, such as this one. If I understood correctly you fixed the issue, but in case you still have problems, contact me again, we can make a version with looser tolerances, however, as I mentioned before, you might check your print settings and calibration (dimensional accuracy) before we start editing files.

X-Carriage for Bondtech Prusa Extruder MK3(+MK3S Add-on) (Revised X-Axis)
by vekoj

Hi Vekoj,

I'm sure you appreciate, sometimes we write stuff like this when we're up to our eyeballs with stuff not working right. I tried to temper my mood but if it appeared otherwise, I'm sorry. I appreciate your work.

Yes, I did think they were links to the extruders for some reason.

I did manage to get everything assembled today perfectly. \o/ So all good. I've learned by now to always choose a loose tolerance version if given the choice. I first tried your puck, which doesn't have the circular extrusions internally, and it fit the pulling perfectly, but it wasn't even close to fitting in the carriage. I dremmelled it a lot, it wasn't great.. That's why I grabbed your step file, removed the circular extrusions, made the nut slots bigger (incidentally, one of the slots has a chamfer, one doesn't) and printed it in pla (bit more accurate) at 99% and it worked nicely. Now regarding the nylon slot dimensions, the problem I encountered is that a nylock nut is too tall to go in the slot. A plain nylon nut is not tall but is 5.5mm wide. Neither was really close to fitting, not a question of just being tight. Similarly, a nylon washer doesn't fit in the circular depression on the back of the carrier either. Obviously not all parts are the same. I find hex nuts to be pretty problematic as inserts like this. Generally, I'd argue for square nuts for slotted inserts, and hex nuts for perpendicular cut-aways, like on the bear carriage --- but hey, we're empowered to fix this stuff ourselves so there's no point in moaning to the guy who put in all the hard work.

I take your point about potentially over extruding. Something to fix now I've got the lovely bondtech extruder installed. Thanks mate :)

No harm done, I sincerely was curious and asked that question so I can prevent people from making the same mistake as you did, I didn't mean no offense either. I have since added few more warnings in the description, some not so subtle at all, hopefully it will help.

I'd gladly fix errors that are present in the design, I am just careful with rushing the edits. After all, I am using the same setup for my printer, I would want the parts to be as "bug free" as possible. Also, others have printed the same parts and didn't report such issues. So, you can understand why I am trying to find the root cause before I resort to editing the 3D models. I think you might be over-extruding a bit, but as long as you got it to work properly, that is all that matters.

You are quite correct, one of the hole cutouts has no chamfer, I will look into it, it must've slipped my radar, thanks for that information. About the square nuts for the tensioner, if you can find square nuts with a nylon insert, I would gladly consider making the edit to accommodate them asap. I prefer to have nylock nuts on the tensioner puck, considering it should be easily adjustable yet hold the set tension under all resonances the parts will be exposed to.

Can you please be more specific about the "nylon washer doesn't fit in the circular depression on the back of the carrier either". I don't use any nylon washers in any of the designs we are discussing. The ones that I mention are metal washers, are optional, and I think I added quite the tolerance so they could fit. A picture of the CAD part would be ideal so I know what we are talking about.

The square nuts you mention on the Bear X-carriage (the square nuts cutouts are same as stock Prusa) actually causes problems, hence my remix removes those 4 square nuts in favor of the hex ones. I see your point about the use of square or hex nuts, please read my previous point about why I resorted to using hex nuts for the tensioner puck. And after all, as you said, I do encourage people to edit the designs to their own liking, that's why I share the STEP files.

No worries about "moaning", feel free to report any issue you encounter, even if it's specific to your case only.

Best of luck with your 3D printing and hopefully the designs serve you well.

Hello, firstly thank you for you work, it is truly appreciated! but........ I am also unable to insert nylock nuts into the idler puck. looking to use the 16t loose idler. any chance you could up enlarge the hole by another .1 or .2mm? I have had no problem with these nuts in all other locations on my build so I don't think they are out of spec. can't print it at 101% else the puck wont fit.

Edit: Just figured out how to import and edit STL in fusion so I'm confident I can make the edits myself.

I made those cutouts tight fit so the nylock nuts dont fall off during assembly with the X-idler, you should try inserting them in the correct position and use slight force, see if that helps. I will gladly do the edits, but seems you are already on the case. In case you need assistance don't hesitate to contact me (here or Facebook).

Oh, and one more note. You can save yourself the trouble of editing the STL file and use the STEP files instead.

Hi, I just installed this mod on my MK3S and the belt is rubbing against the carriage. I've measured the x-axis ends and compared to the stock MK3S and the motor here is 3mm higher. The idler here is also about 2mm higher. I wonder what is the reason for this change. I ask because it says it's compatible with MK3S extruder and it doesn't look like it is. The stock x-axis ends worked just fine.

Please read the instructions carefully, these X-ends are compatible with the stock MK3S extruder only if you use the X-carriage included linked in the description (https://www.thingiverse.com/thing:3560132).

X-Carriage for stock Prusa MK2.5S / MK3S Extruder (Revised X-Axis)
by vekoj

Oh, I see now. I read that part twice but would have never guessed that meaning. I'd suggest clearly mentioning it's not compatible with stock MK3S extruder since it's not compatible with it. It took some time to install it only to understand I need to revert.

What is the reason for the motor and idler position change after all?

I thank you for the suggestion. I might make the language a bit more clearer, sure.

People are using these X-ends with their stock MK3S extruder, so I beg to differ that it is not compatible, granted you need a custom X-carriage with the belt path modified but you keep 100% of the stock extruder and its functionality (compatibility with stock firmware).

The reason why the belt path is different from stock is because the X-ends are now compatible with multiple extruders (so you can switch if you wish to do so without changing your X ends) and they are modular, compatible with 16t/20t idlers, again, without the need to change either X ends or X carriage once you switch over to the custom one provided in the post.

I apologize for the inconvenience, but there were plenty of warnings in the description and the only place that mentions the compatibility with stock MK3S extruder, has a clear link to the custom X-carriage.

Perhaps there might be less confusion if the X carriages were included with the thing files on this page. I somehow missed the need for the revised carriage as well. Is the spacing between the rods slightly different from the stock assembly?

With so many versions of the files just for the X ends, I think it will make more of a hassle if the carriages were included as well, which they have their own versions to add to the confusion. The description has several places where this is explicitly noted.

The spacing between the rods is the same as stock Prusa I3

That makes sense, thanks. I'm working on my own extruder and I tried to keep the original belt layout for those who don't want to change the x-ends. Not sure which way to go now :) Working on mods myself, I do appreciate the effort it takes to make them, you must have spent a lot of time designing and testing.

My 2c. As you noticed the difference between the belt paths is minor, so adjusting the X carriage for either stock or modded X ends for your planned extruder shouldn't be much of a challenge. So, I'd focus on the extruder design and adjust the belt paths later depending on what you decide (maybe even two different versions). My take on the situation anyways.

Thank you for your kind words. Best of luck with your mods and if you plan on using any of the resources posted here, feel free to contact me, I'd be glad to help out if I needed.

I will print these parts for my MK3s Update, But i have a question to the right Idler, which version is better the two or four screw version?
And a other question i have is, why are the screwholes for the engine so mutch higher in your version as from the original?

I have see that these problem from Cristian2281 on Apr 20, 2019 was reportet, is already an upgrade available? Because I want to use the original MK3s Extruder.

If in doubt which idler to choose, I'd say pick the one with "two screws". As stated in the comments, the "four screw" has its own benefits but it's trickier to fine tune and easier to mess up if you do it wrong.

The holes are "much higher" than the stock ones because the belt path is higher (for number of reasons), and the motor positioning just reflects that.

The problem you saw happened when Christian2281 used the stock MK3S X-carriage instead of the modified one provided in this listing as compatible. Make sure you print the X-carriage as well and it will work.

"The problem you saw happened when Christian2281 used the stock MK3S X-carriage instead of the modified one provided in this listing as compatible. Make sure you print the X-carriage as well and it will work."

I want use the MK3s carriage, no other!
I will probably try to port your back again that the hole dimensions correspond to the original again.

https://www.thingiverse.com/thing:3560132 is the exact same MK3S carriage, only edit is to fit the Revised X-Axis belt path. But if you insist on editing the X-ends to match the stock MK3S carriage, STEP files are included. Just keep in mind the belt path and alignment, on both X ends, motor and idler. Best of luck.

X-Carriage for stock Prusa MK2.5S / MK3S Extruder (Revised X-Axis)
by vekoj

Hello, printed the idle tensioner twice for stock prusa. Both times idler has no room to spin, is this the way i suppose to be? outside size, is perfect.

Is it tight on the sides?

If so, I have since updated a version with loose tolerances for the idler pulley (width), https://www.thingiverse.com/download:6507553. Hope these help.

yes, this worked great, thanks :)

This is a post containing the X-ends of the X-axis and compatible carriages for two extruders for the time being, stock MK3S and Bondtech Prusa one. Both extruders use the original E3D hotend you linked.

So im converting from a stock MK3S and the idler system is a bit different- it uses an m3 with a lock nut instead of a dowel. Does anyone have a clever workaround for this? (I need a way to secure the idler in the tensioner without a dowel)

errr, should i say: more clever than taking a hacksaw to an m3?

A disc grinder would do the job as well ;) Jokes aside, the M3 (or M5 depending on the version) DIY solution works quite fine. Use a longer screw (M3x40 from the spare bag will do the job) and extract the non threaded part, that way the bearings of the pulley wont rotate on the screw threads, like the stock one does. File down the edges a bit, and you got a perfectly working pin. But, if you really want a proper pin (tolerance wise), I'd suggest the gage pin route, which will also require a hacksaw/disc grinder (cutting tool) unfortunately.

Alternatively, I think Printed Solid or similar retailers had dowel pins that could work.

I went the gage pin route myself, the cut doesn't have to be all that precise (even for the screw), there is plenty of room for slight mistakes.

Hope this helps.

The hole for the dowel pin is tight enough to keep it in place with a pressure fit (secure the idler in the tensioner). The pin is secured further, when you insert the tensioner in the X-Idler.

Hey, nice work!

Is this only compatible with the original Prusa style trapezoidal nuts?


They are designed with the POM trapezoidal nuts in mind, but a small edit should make them compatible with brass ones if thats what you are after.

Yeah, I'm using a custom designed machine inspired by the Prusa and I'm also rocking POM nuts, but mine are modeled after the standard brass nuts and not the Prusa ones. Would be awesome if you could provide files for my setup. I'm also not dependent on endstops as I'm using StallGuard so endstop mount on the motor side is not needed. Thanks man!

There are STEP files provided in case you want to do the edit yourself, otherwise I'd ask you to give me some dimensions or better yet a 3D model of the hardware you use, I will try to find time to do the edit myself, although it will take some time, depending on when I get some free time to edit it.

So I installed the version you have to fit the MK3s stock pulley and the Bondtech and it is really great in terms of adjustability. The only issue I am having is that first of all the belt is really difficult to get all the way into the carraige and no matter what I try I was not able to get it fully in the slot. Given that I would have thought to re-print with a bit less extrusion, but because of the following problem I don’t know if that would work. When I did apply tension even though the belt was not totally seated laterally, then over time the belt began to slowly slip out of the carraige towards the pulleys and I would lose tension. This would indicate that the carriage should be a tighter fit and printed with more extrusion. So I’m kind of lost between the two competing issues. What would you recommend? Do you have any tricks to seat the belt fully in and also so that it doesn’t slip when applying tension?

I am able to print and getting good results but the loss of tension over time means that the tension will get too low eventually.

Much thanks.

Not sure what happened with the comment and why it got flagged for moderation. Hope this one doesn't have the same fate.

Is it a 2GT belt that you are using?

The belt cutouts on the x-carriage have two set of tolerances, somewhat loose at the start and the last mm or two pinches the belt. It's a balance between being easy to insert and keeping tension. I used the loose tolerances only in iterations before, and it produced similar results like you found, the teeth were slowly slipping so I added the pinch at the end which in my crude tests, helps a lot.

Before any assembly, clean up the x-carriage belt cutouts from printing artifacts (stringing, blobs), with a nylon cleaning brush or similar. What I suggest is using a tool to push the belt in. I used a metal nail file found on a Swiss army knife but anything with similar specs should do, if in dire need you can print a 0.8-1mm tall rectangle, just avoid a tool with sharpened edges.
Rest the tool along the belt path and start gradually pushing the belt in, applying pressure from the start (where the belt enters the carriage) to the end of the belt in the carriage. No need to push it in on the first try, give it few passes. Also one trick that could help is handling the non toothed side of the belt with your hands, the skin oils should make that side slippery enough to make it easier to insert (or something similar though I do not recommend using any lubricants)

If you do decide to reprint the x-carriage, I'd suggest printing it at slower speeds rather than messing with the extrusion multiplier (unless its way off). Shifted layers, stringing and similar artifacts will affect the tolerances a lot more than the extrusion multiplier (again, unless its way off).

Comments deleted.

2GT Gates belt?
Before trying to insert the belt, use some brush or similar tool to clear the pathway of any stringing and similar artifacts. When inserting the belt, try using a small thin tool, I used a metal nail file which has somewhat dull side, allen key helps, but it has too much of a point pressure (surface area) to help much.
Push the belt along the path, starting from the place the belt enters the X-carriage and moving along the path, trying to insert the belt one part at a time (not necessarily trying to seat it fully on the first try), do it for the full length of the belt that is engaged with the carriage.
If you resort to reprinting the carriage, I'd recommend printing it at slower speeds rather than messing with the extrusion multiplier (unless its way off). Slightly shifted perimeters and artifacts will be more influential than the extrusion multiplier (again, unless its way off).

I had the same issue you mention with previous iterations of the carriage. The upper half of the cutout (x-carriage) has tolerances I've used before, and they work ok, but you can notice that under tension, they do tend to slip a bit from their intended cutouts, and I'd bet after some time they will skip a tooth. Same thing you've observed.
So, the last mm or two has bit tighter tolerances. The goal was, the belt can be somewhat easier to insert (the looser tolerances above), but can be pinched in the last few so it holds tension. I've tested it with far more tension that the belt will need to be at, and that last "pinch" helps a lot.

TL:DR If it's a 2gt (or even gt2) belt, please try to push the belt with something similar like the tool mentioned above (all depends what you have near by, just avoid sharpened edges as it will destroy the belt). It needs slight "persuasion" for the last mm or two, but it shouldn't be that hard to insert with a tool, just make sure to push along the length of the belt that is engaged with the carriage.

Comments deleted.

Just wanted to check as I really want to print this off. I have a Haribo MK2.5 and converting to an MK2.5s. Am I right in printing X-Idler-3.01b_StockLike.STL & X-Motor-3.02b_MK2.5.STL. I wasn't sure which tensioner as of yet to print

Use the tensioner version for the hardware you have available (or plan to use). They are all interchangeable, meaning you keep the belt path the same regardless of the version. Which idler pulley do you have/plan to use?

Regarding the X-ends, make sure the X-motor is compatible with MK2.5 (which seems you already did), the X-Idler versions are both compatible with either MK3 or MK2.5 X-motor printed part.

Thanks, the main hotend I was going to use the Prusa stock 2.5s stls, but love your X axis ends as they are more adjustable

Just make sure to use the MK3S (technically MK2.5S) X-carriage STL linked here, and not the stock one.

Will do thanks. Will queue them up to be printed when the X-ends finish over night. Glad I have two printers right now as I made a last minute colour change when the Prusament Carmin red turned up... turned out to be a lot of reprinting

Hey thanks for all your work on these projects. Two questions though. Is there an “ideal” idler size to use for best belt path alignment? I have both 16 and 20 pulleys so in choosing I didn’t know if one was better or not. I guess it could be that they are both the same because the only belt path that has to be totally straight is the upper one and you could achieve this with with either pulley.

The second question is regarding the size of your Bondtech BMG carraige as I will be doing that upgrade as well. I know the other carriages people are using for the Bondtech extruder on the MK3S are bigger than the stock MK3S carriage and so one needs to use custom firmware with changed Z distance to account for that. For your carraige, if you know, do I use the BMG firmware or is it compatible with the Prusa firmware?

Much Thanks!!

I've used 16t (smooth equivalent) idler with dual bearing with no problems at all. But fact is, there are sub par quality 16t idlers out there, more so for the toothed ones. And also the fact that there can be a mismatch of the tooth profiles (2GT and GT2) of the belt and pulleys. I personally went with E3D ones, motor (https://e3d-online.com/gates-powergrip-pulley-16-tooth-6mm) and idler (https://e3d-online.com/gates-powergripr-toothed-idler-6mm).
I would consider the E3D idler "ideal" because of the quality of manufacturing (as far as I can tell so far) and has the correct profile with the 2GT belt.

About the bondtech extruder, Prusa reduced the height of their extruder when they introduced the MK3S. Bondtech extruder complies to the MK3 specs and firmware. The carriage plays no role with the Z distance you mentioned, the extruder does. So, to answer your question, yes you will have to use firmware that is meant for the Bondtech Extruder, rather than stock MK3s one.

Oh and yes, the belt path with either 16t or 20t will stay in the same (correct) position, the idler puck compensates for that. At least the top part will, the one that matters.

Is that with stock MK3S Carriage or the one I included in the files marked as compatible?

Stock.I was under the impression that it works with stock. I guess I’ll have to reprint the carriage.

My sincere apologies, compatible carriage can be found here https://www.thingiverse.com/thing:3560132. Although I didn't change much on the MK3S, I did have to change the belt path to make it compatible. I am currently editing the details to add as many warnings as possible to avoid this misunderstanding in the future. Would you please point out the description that led you to believe so? Thanks

X-Carriage for stock Prusa MK2.5S / MK3S Extruder (Revised X-Axis)
by vekoj

You don’t have to apologise, I just assumed it’s a straight swap with Prusa’s X axis. I might be able to print the carriage parts without changing the X axis back to stock.

Nice work! Thanks a lot for sharing!

Very professional, many many hours but it shows!