Quick-Fit X carriage and Extruder - LM8UU

by RichRap, published

Quick-Fit X carriage and Extruder - LM8UU by RichRap Mar 20, 2012
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This is a Linear bearing LM8UU X carriage to allow quick change of Extruders and other tools on your 3D printer.
It has compatible bar spacing for Mendel, Prusa and MendelMax

Update 21st - March - Added Greg/Wade extruder adapter plate and all the Sketchup files so you can make whatever adapter plates etc. you may need.

Added 31st March - Belt clamp and Low profile catch together - as requested.


Both parts print vertically, join them together with 20mm M3 bolts.

The Linear bearings slide in and secure with a zip tie

It has a belt adjuster on one side of the belt clamps - see photos

The Extruder is based on Greg's excellent design, with a few mods and the extensions allow it to fit on the Quick-Fit X Carriage.

You need two x M4 (13mm) 624 bearings for the Quick-Fit Lever.

It also has a fan mount on one side.

It's designed to be expandable (easily made wider) by adding spacers between the two halves - without taking off the printer. - just in-case you ever need more room to fit triple extruders !

Check out my Blog post for further details -

A Video of it in operation can be seen here - http://youtu.be/ffICsLWzn2o

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How can i make this work for my prusa i3 or is there no reason?

Has anyone tried to adapt this to a Velleman K8200/3Drag printer? As the bed is what moves X/Y, the head only moves in Z - so it doesn't need the bearing mounts. I've tried, but I am terrible with CAD.

The K8200 has only 2 screws to remove and change the extruder.
I print few extruders with ABS and this mod (http://www.thingiverse.com/thing:819504) in 1.75 and 3mm, all is easy to change with fast electric plugs (Marklin train connectors) Just few minutes are needed to change the extruder ;-)

You can find all original k8200 parts are to print on thingiverse, but some plates have to be repaired with netfab basic.
Just have a try

extruder k8200 mod 1.75mm
by glloq

Hi, How would you use this for something like the e3d v6 hothend. How would we secure the hot end to the extruder ?

Great Design - Very Rigid due to it's Box Style Construction + 4 Corner Mounted LM8UU Bearings - Extruder's fit very tightly & give good results when printing - Chucked our old X-carriage in some acetone to make ABS glue and converting other machines to use this the Richrap X carriage - Had no Issues at all Sliced well in skeinforge & Printed out fine in grey ABS . the only changes made was i added a little extra material on the fan end extruder clamp as i plan to be swapping a lot of extruders & wanted to be 100% sure it was strong enough for 100's of Swaps - THANKS Richard great design.

The fan side of the carriage will not slice in Slic3r as of 3-19-14. It comes out as a badly porous mess, even though the file reads as fully compatible. I can't get it re-save in Inventor, so I just wasted hours printing the other half of the carriage and latch, right? What's going on here?

Thank you for the wonderful work! I have printed out the carriage and would like to use the extruder files with an E3D hotend. Is this possible? And if so, how would I connect the E3D to the rest of the assembly? Thanks for any help you can provide on this :)

I'm assembling mine E3D now, from what i have seen, it can be mounted with no problem, don't know how easy it would be to remove it, but it goes through if you align the fan parallel to the rods.

I have made an X End Motor part that goes with it. Its originally made by Jonas Kuehling but my version puts the motor a bit further from the threaded rod, this allows for better alignment of the GT2 Belt http://www.thingiverse.com/thing:155127http://www.thingiverse.com/thi...

X Axis holders
by Tuim

Do you think that this would work w/ a printrbot simple?

It's a bit big I expect, the simple is quite a tiny printer. But I'm sure a quick-fit carriage could be made for the simple.

Can you please recommend what gears to use for the Greg's Wade extruder you've included? I tried printing the fishbone gears from the "official" files here: http://www.thingiverse.com/thing:18379http://www.thingiverse.com/thi... but the large gear is jamming up against the carriage! Image of what I'm talking about (large gear is touching carriage): http://imgur.com/6SwV1ekhttp://imgur.com/6SwV1ek

Greg's Wade reloaded - Guidler, Tilt Screws, Fishbone Gears

I always use the Triffid Hunter versions - http://www.thingiverse.com/thing:10707http://www.thingiverse.com/thi... they fit perfectly.

Parametric Herringbone Gear Set for Greg's Accessible Wades

Rich, Could you upload the model file for the extruder? I want to try to modify it to take a nema 14 motor; try to reduce the weight of the completed carriage for less inertia: more speed. Speed is good. (or is the extruder model file - with your quick release base plate - elsewhere on thing-v)
Many Thanks

The quick fit extruder is part of this archive, or do you need something else? - a NEMA 14 version would be nice - you may want to scale it all down and also use smaller gears - like the ones I used on this 'Huxley' sized one - http://www.thingiverse.com/thing:24307http://www.thingiverse.com/thi...

Mini Quick-Fit Huxley sized extruder #30DoC
by RichRap

good day sir! is chocolate extruder available in the market?? Need it for our project..hoping for your response, we only have limited time left..please help us..thanks

can I get a design like this to fit a prusa i3?

Hello Rich,

On some of the threads I follow on the reprap forum you had mentioned that you wanted to try the metal magma hotend. Did you happen to get one? If so do you have any tips on mounting it to the quick fix? Did you use the aluminum mount?

Thank you,


Hi Cameron,

No, not got hold of one yet, I did see they were now available from reprapdiscount, so one way I'll get one to try out.

I hope the metal plate fits between the quick-fit hole, but for the PRUSA nozzle I did make a modified extruder base to sit the metal plate into, that worked really well.



I had trouble printing the small supports also as they are only 1mm wide. I used my default extrusion width of .69 and when viewing the Gcode it only output 1 line at the supports. Going down to .490 yielded 2 lines at the supports. .500 still left one area with 1 line not sure if this was a Slic3r issue. I may reprint and see how they look.

Having difficulty printing the narrow supports next to the screw holes that join the two x-carriage pieces together. Tried altering the design but neither blender nor openscad will open the stl files (openscad complains about the wrong winding order).

I dont suppose you would be willing to create a version that will work with the self aligning bronze bushings.

I believe they are 16mm OD with a bit of a flange. I'll get exact measurements if you are willing and need them.

Thanks in advance and hoping to switch over to your carriage without having to disassemble my well tuned mendelmax!

I'm not sure how well bronze bushings would work, I wonder if you could print a holder to 'convert' a bushing to the same size as a LM8UU or 10mm LM10UU? that might be the easiest way.

I thought about that for a while, but was hesitant to add extra pieces to cause binding. Additionally I had initally printed the copy for the LM8UU which was really just not going to work with my bushings even with adapters.
The good news is that Zerocool from below hooked me up with his files to print your carriage compatible with my bushings. The bad news is that my hotend had a bit of a disaster while printing the quick fit extruder body. I'll post pictures when its all put back together!


Just wondering what X ends you would recommend. I've got some adapted Prusa ones, but with the motor mounted on the outside, the belt cog is well out of alignment with the x carriage belt clamps. From the pictures on your site it look like your motor is mounted so it is inbetween the rails, but I can't find one that is similar.

Many thanks,


Hi Darren, 
I do like these from Jonaskuehlinghttp://www.thingi... make sure to check out the derivatives alsoCheers,Rich.

Those were the ones I'd actually printed out to use originally, but as mnadamn says, the belt mounting points are way out of alignment using any X end that involves the motor mounting on the outside of the part, which is most of them. :(

Hey RichRap, I was also wondering the same questions.  I have 3d modeled the stl files and mocked up a MendelMax and the belt mounting points are 7.2mm further outside of the center of the X-Axis than Jonaskuehling's X-ends allow.  Is this ok?   I would assume that you would need these to line up pretty well so that the belt doesn't slip or worse eat itself up.

Sorry for the delay - If you space the motor away from the mount using 2 x M4 nuts and use longer M3 bolts for the motor mount that should make it line up.
I have changed over to a modified version of Jonaskuehling's X-ends that use M10 ACME leadscrews, this was modified with a bigger motor mount that lines up with the X-carriage.

I can upload it ad a derivative if it's of any use to anyone, but you will need to use M10 leadscrews and lead nuts.

Or modify the Jonaskuehling version by pulling the motor mount out moving the pulley further away.

I too have a Prusa i3 and I would like to use this quick fit carriage. I would need the X ends and I tried the above link and tried searching on Jonaskuehling and could not find the files. Could you direct me to the files that will work with a Prusa and your project. Thank!

This looks like exactly the part I want but i cannot see how it works with a J-head like mine, mounted on an aluminium plate.

Will this setup work without issue? Im guessing the plate would push up the extruder too much to fit under the latch?

I saw that you mount your j-head differently but I couldnt find these m12 rail mounts particularly easily, nor am I able to drill a 16mm hole that I'm aware ...

My j-head looks l
ike this for reference


Well you don;t need to use the Aluminium plate with a Jhead, the grove mount can fit into the extruder body - just take a look at this derivative - http://www.thingiverse.com/thing:28916http://www.thingiverse.com/thi...

You may have some issues, but I'm sure they are not all that hard to overcome.
You should be able to drop it in the hole and slide in under the grip then angle it down for the latch, you can fit quite long hot-ends in this X carriage.

Let us know how you get on.


quick fit extruder for J head hot end
by olekdh

Finally got the thing working properly with new carriage, extruder, electronics (dont ask) ... 

Thanks for the link Rich the extruder works perfectly

Is this meant to be used with the wooden plate that holds the makergear groovemount hotend? Seems like the basic design would work but would need a taller derivative?

Sorry, I'm not familiar with Makergear hot-ends at all, but you can fit quite long hot-ends in this X carriage.

Just Printed one for self centering brass bushings for my new machine. If it works out ok I will post it as a derivative.

I Like it, very nice job

Make sure you check out the Awesome LM10UU version by akhlut - http://www.thingiverse.com/thing:24505http://www.thingiverse.com/thi...


Was it a modified version of yours? I'm very interested on a 10mm rods version.
There isn't that akhlut's part :-(

We do have another 10mm remixed version by mnadamn here - http://www.thingiverse.com/thing:37675http://www.thingiverse.com/thi... - looks good.

10mm Quick Fit X Carriage
by mnadamn

Big Thanks! I'm going to build a MendelMax 1.5+ in the next months and you're a great source of inspiration.

Thanks for your great work! I would really love to have a quick fit extruder running here but unfortunately i'm not running LM8UU anymore but the much better IGUS RJMP01-08 gliders. They're a bit wider and i don't see a chance to easily modify the sketchup files to make the bearing holes a bit wider - do you?

Hi, I found some STL parts for IGUS bushings directly on the IGUS website, and as they were ... a bit larger, I designed printable IGUS Bushings to replace my LM8UU and LM10UU, And they yet working very well on my Y carriage !!! they are really less noisy than my "poor" LM8UU ...

I'm going to Upload LM6UU, LM8UU
amp; LM10UU printable linear bushing, calibrated to be printed as well with a 0.5mm nozzle !!!

And I think RJMP01 are the "old" version cause Igus designed new RJMP revision 2, to fit exactly LMxUU bearings, I think to match industry and to allow "easy" switch between IGUS and Standard Bearings.

Not all that easily, I was crossing fingers that someone would have made a parametric version by now...;) so I didn't have to make another one for 10/12mm rods- :)

where are the little "rams" for belt tightening? I plan to actually start using this soon, and realised I don't have any

Hi James, the little 'rams' are actually a bit of polymorph with a M3 nut in them :-D

I was going to design a nice little belt pusher with captive nut, but didn't find time, then I built one up and just used some polymorph and it worked so well I didn't change it.

I'm sure Nophead has a similar system on the Mendel90, and I was going to 'borrow' his belt pusher next time I built o
ne up.

I've modified this (with my dremel) to work with the budaschnozzle, now to learn sketchup so I can get a model up!

Hi !!! I adopted your carriage + gregs extruder and herringbone gears for my first reprap and still impressed !!! nice work.

I'm actually working on a "GIANT" MendelMax, and I don't want to use a regular X-Carriage, I wanted to know if it's possible, to create a version for both LM10UU and LM12UU (LM12 just in case) cause i'll probably use 10mm smooth rodes for my MendelMax, (45x45x34cm build area)

Hope you can deal with it !! It would be awefull !!!

Thank you ;)

I echo that sentiment...an LM10UU version would be delicious... I'd modify the sketchup files myself, but I'm terrible with CAD in general.

We gonna modify those pieces, I think, when it's ok we must post as derivative on thingiverse, stay update.

We also gonna modify X-Ends (motor/idler) with some improvements, like LM10UU and a better align for the motor/belt to fit the Quick-fit X-Carriage specs.

Cool, LM10UU would indeed be a great derivative, I would use it in my next 'MEGAMAX' build. 8-) good luck with the Giant build - remember you will need a big heated bed to print that massive!

Up, for those interested in, here is my BOM (mostly french providers/european)

For a cost around 600€ ;)


What about "extruder adapter plate" only?

What do you need? I uploaded a Greg/Wade adapter plate? do you need something else?

I need file, contain ONLY "Greg/Wade adapter plate" without other parts!

Very nice!

But of course I want more :) I am thinking if the extruder was rotated 90 deg, then two or more extruders could be mounted side by side... I guess that might be difficult to cater for.

I did start designing a four position plate with three extruders at 45 degree angles, one straight and small bowden tubes to the hot-ends, but it's getting quite complicated and heavy, so I'm re-thinking that.

this is very cool, i've replaced the x-carriage on my second prusa2 with this, I have everything apart from the extruder. I'll add your mounting options to the gregstruder in openscad and add as a derivative if that's useful for anyone. I'll also be adding a pen holder for this mount. Thanks :)

All printed: now - search 624 bearings...

Wow, this quick change extruder mount is epic :) I MIT print a little one and mod up my Huxley ;) Might I recommend any "universal adapter plates" be tagged as a derivative of this object. The idea of quick mounts/releases and universal connections shows that this project is getting somewhere ;) You rock Rich!

Is the hole large enough to fit a Budaschnozzle in it?

I expect so, it's a very big hole - how big is a Schnozzle? I don't have one yet.

Its width is the exact size of the hole in the standard prusa X-carriage.

Is there any way you can make an adapter to mount between the extruder of a person choice and this quick release? This items quick release allows use of any extruder you want http://www.thingiverse.com/thing:17651http://www.thingiverse.com/thi... , looks like yours would also if you made a bottom interface to go between any extruder and the tie down.


Yes, I did a Greg / wade adapter plate (pic on my blog) I'll upload the adapter and also some other templates so people can make their own plates. I have not needed to test the adapter plate, but it's the correct dimensions.

I have a dual extruder plate in the works, one of my main aims with this X carriage was not needing extra plates but modify the extruder models to directly to fit the carriage.


I'm really just happy if someone else finds it useful.

And Thanks for the link, I didn't spot that one, looks nice.

I can't wait to see it. Reason I don't want to adapte each extruder is I have 4-5 different extruders I play with, 2 paste extruders, 1 wades, 2 brustruders, 1 pen plotter, 1 laser holder... all of them where made in different programs, some of which the licence for are worth more than my 3 reprap combined :)

I shall be sucking up tons of bandwidth refreshing the page till you share! Thanks dude! Printing 3 new x carriages atm :)

:-D ok, they are up, the Greg/Wade as a sketchup and STL plate and the Sketchup files for both sides of the Carriage.

Let me know if you have any problems, have fun.



Having completed my second Ronthomp Mendel printer, I had occasion to swap extruders, a Wades and a Greg Frost. What a pain! This looks like just the ticket. Thanks!