Quick-Fit X carriage and Extruder - LM8UU

by RichRap, published

Quick-Fit X carriage and Extruder - LM8UU by RichRap Mar 20, 2012


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.

Recent Comments

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

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!

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.

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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 - youtu.be/ffICsLWzn2o


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rrosinha on Jul 3, 2014 said:

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

3DPrinterpunk on Mar 30, 2014 said:

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.

Artesian on Mar 20, 2014 said:

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?

bigpizzle on Nov 13, 2013 said:

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 :)

cr3a7ure on Nov 14, 2013 said:

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.

Tuim on Sep 23, 2013 said:

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/thi...

sofiadragon1979 on Aug 27, 2013 said:

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

RichRap on Aug 29, 2013 said:

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.

jasonwebb on May 26, 2013 said:

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/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/6SwV1ek

RichRap on May 30, 2013 said:

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

johnpanter on May 20, 2013 said:

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

RichRap on May 30, 2013 said:

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/thi...

marj03 on May 18, 2013 said:

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

mastermonk on May 14, 2013 said:

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

Cameronm on May 12, 2013 said:

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,


RichRap on May 14, 2013 said:

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.



Spk64 on Feb 14, 2013 said:

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.

Hexdoll on Jan 15, 2013 said:

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).

billynup on Dec 13, 2012 said:

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!

RichRap on Dec 20, 2012 said:

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.

darrenp on Nov 11, 2012 said:


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,


RichRap on Dec 5, 2012 said:

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

Clem2k3 on Sep 14, 2012 said:

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


RichRap on Sep 14, 2012 said:

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/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.


rrhb on Sep 13, 2012 said:

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?

RichRap on Sep 14, 2012 said:

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

zerocool5878 on Sep 2, 2012 said:

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

RichRap on Sep 2, 2012 said:

I Like it, very nice job

RichRap on Jun 13, 2012 said:

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


GordTheRogue on Oct 30, 2013 said:

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

Helmi74 on Jun 7, 2012 said:

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?

PropsFactory on Jun 15, 2012 said:

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.

RichRap on Jun 13, 2012 said:

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- :)

jamesglanville on Jun 6, 2012 said:

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

RichRap on Jun 13, 2012 said:

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.

gannon on May 4, 2012 said:

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

PropsFactory on Apr 23, 2012 said:

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 ;)

Anonymous on Apr 26, 2012 said:

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.

PropsFactory on Apr 23, 2012 said:

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

For a cost around 600€ ;)


Siorinex on Apr 20, 2012 said:

What about "extruder adapter plate" only?

RichRap on May 2, 2012 said:

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

bobc on Apr 13, 2012 said:

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.

RichRap on May 2, 2012 said:

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.

jamesglanville on Apr 12, 2012 said:

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 :)

Siorinex on Apr 11, 2012 said:

All printed: now - search 624 bearings...

idolcrasher on Apr 10, 2012 said:

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!

devzero on Apr 8, 2012 said:

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

RichRap on Apr 8, 2012 said:

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

Spacexula on Mar 21, 2012 said:

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/thi... , looks like yours would also if you made a bottom interface to go between any extruder and the tie down.

RichRap on Mar 21, 2012 said:


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.

ronthomp on Mar 21, 2012 said:

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!