QU-BD One/TwoUp Extruder V11 with video

by laird, published

QU-BD One/TwoUp Extruder V11 with video by laird Jan 8, 2014


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This is a replacement extruder for the QU-BD One/TwoUp printer. It replaces the wooden parts, and holds the hot end.
It replaces the wooden extruder and screws to the kit's gantry mounting parts. Or even better, it works perfectly with http://www.thingiverse.com/thing:223327 which is a one-piece printed mount plate that clips onto the linear bearings!
It can be used two ways.

If you have a large format printer, you can print UpGrade.stl, which contains all of the parts of the extruder and also the mount, completely replacing the entire MDF assembly, making it much sturdier and easier to use.

1) Use just the body and lever, with the original screws, spring and bearing, to replace the MDF extruder. This works well, and eliminates the fiddly wooden pieces that break.
2) Add the fan venting, to attach the cooling fan to the extruder, and then blow the air down onto the print. This cools the motor and the print, but it requires updating the firmware on the controller board (as documented by QU-BD). Very optional.

  • The advantages are intended to be:

  • Easier filament release and engagement (press a button vs. screwing an M3 socket head screw).
  • Holds the hot end more firmly (mine is wobbly).
  • More durable than wooden parts (two of which have already cracked for me).
  • Integrates fan into extruder, to cool motor and filament above the hot end as well as the print.
  • Able to add a fourth screw into the motor (the QU-BD design uses three).
  • Able to print replacements
  • Parametric design so it's easy to tweak and extend. If you like OpenSCAD anyway, which I do.
    V3 update:
  • Angled the vents from the extruder to the print to be further from the hot end. Don't want them to melt.
  • Added guides to lock halves of parts together when assembled.
    V3b update:
  • Got the 'plated' items properly leveled. Oops. Prints fine now, all parts are "tight", at least on my printer. I look forward to additional feedback.
    V4 Update:
  • Added ridges between the two halves so they align when assembled. Better than the v2 guides.
  • Made hot end even tighter.
  • Made lever longer, so it should be easier to load/unload filament.
  • Made a bit thicker, so it works with the QU-BD provided screws and MSD mounting plate.
  • Corrected some minor bugs.
  • Made a few walls thicker to improve prints.
    V5 Update:
  • Made lever much stronger. If you're using v4, print the v5 lever and swap it in. The other parts are unchanged.
  • Generated all of the individual parts, and plates of pairs, in addition to the plate of all parts, so you can pick which you want to print.
    V6 Update:
  • Merged the FanVent and Vent parts (into FanVentPlated5.stl). Making them a single part makes it stronger. Also, angled the vent to clear an obstruction when the extruder is at the left edge of the build plate. Eliminated the wall facing the extruder body, giving more airflow and improving printability. This does require gluing the vent to the side of the extruder body to seal airflow, though.
  • Added a 'guide' to the lever (LeverPlated6.stl), helping keep the filament on path to the bearing and the hot end.
    V8 Update:
  • Merged the fan vent and the associated vent into one piece, so it's stronger, and has improved air flow. Also, angled it so that it avoids an obstruction when the extruder is at the left edge of the print bed.
  • Deleted all of the old files, as it was getting confusing. These days, if you want to plate them you can do that yourself.
    V9 Update:
  • Modified vents so that it fits if the lever is routed to the left or to the right, and allows full travel on X axis.
    V10 Update:
  • Increased clearance between lever and the extruder gear.
    I'm pretty happy with this so far. You can use the extruder body and lever to replace the MDF extruder, which is quite fragile and hard to load, which was my primary goal. And you can add on a fan and venting, which will keep the motor cool and improve print quality, if you like.
    V11 Update (thanks to tommythorn for the request)
  • Spring is 2mm shorter, which should work for more people's springs without needing to insert the spacers.
  • Spring support is much stronger.
    The pictures on this Thing show the assembly, and there are written assembly steps in the instructions tab.

Jim Younkin produced a nice video (in 3 parts) of the assembly process:

Nice job, Jim!


It's customizable, to make it easy to generate all of the parts, but you shouldn't need to customize it, because all of the dimensions are from QU-BD's DXF files. If you don't want to use the fan for venting, print UpExtruderBody8.stl and UpExtruderLever8.stl. If you want to use the fan as well, also print UpExtruderFanVent8.stl and UpExtruderVent8.stl. This will give you: - The body front and back - The lever front and back - A vent (optional) - A fan vent (optional) You will also need the three M3 screws, bearing and spring from QU-BD's extruder kit. And to attach the fan you'll need four short M3 screws. Assembly: - The pictures show this sequence. - Assemble the lever. That is, mate the two halves of the lever, with the bearing on the round part. Put it aside. - Set the extruder motor, pointing up, with the gear installed per QU-BD's instructions (i.e. tightened to the motor axle, close to the motor). - Body half with the screw holes lined up to match the motor. The semi-circle cutouts for the hot end and vent should be facing you, with the slot for the spring on the left. - Put the hot end into the larger semi-circle. The groove in in the hot end mates with the ridge in the extruder body. - Put the spring in the vertical slot that's the same size as the spring, along the left edge. It should be mainly inside the body, and touching the bottom of the lever. Note: the extruder is symmetrical, so you can mount it with the lever to the left or to the right. The "out of the box" firmware is configured or the lever to be on the left. If you prefer the lever to the right (I do, as I am right handed) you will need to configure the firmware to reverse the direction for the E stepper. If you don't know what that sentence means, keep the lever to the left. - Check that the center of the hot end, the bearing, and the notch in the gear are all centered on the same height as the middle of the extruder, so the filament can go straight through the extruder. You may need to loosen the gear and adjust its position on the motor axle so that they all align. - Put the other half of the body on top, so that it holds the lever and hot end and the spring in place. - If you want to use the fan vent, stack it on top, so the plate lines up with the screw holes, and the vent box sticks up. - Either use the printed mounting plate, or find the wooden plate that's shaped like a fat lower case H top, with the screw holes aligned. So it's in the same position as QU-BD's instructions, then ut the two gantry/belt guides on top of the wooden plate, same as QU-BD's instructions. - Put the three screws into the three holes in the mounting plate - either the printed one or the wooden pieces. That is, screws in both of the top holes, and the bottom right hole. Like in the photo. - Now lower the plate and screws over the fan vent plate (f you're using it), then the extruder body, so that the screws go into the corner holes and through the body. You might need to press the lever in a bit to get the screw to go through. - Lift the extruder so that it's against the plate, and the three screws stick out the bottom. - Lower the extruder (and screws, etc.) over the motor, and guide the screw tips into the motor mount holes. - Tighten the screws so the whole thing is snug on the motor. - Hold it up so that you can see how it'll fit against the gantry, with the plate towards the gantry and the motor towards you. Make sure that the lever is pointing away from the Z axis worm gear, and the opening for the fan is pointing towards the Z axis worm gear. If it's the other way around, remove the screws, separate the motor, extruder, and mounting plate, and flip the extruder around so it's facing the right way, and reassemble. Make sure that the extruder gear is still lined up with the bearing - you might need to move it on the shaft. Optional: - If you want to use the fan to cool the extruder, you need to upgrade the firmware on the controller, per QU-BD's instructions, to enable the fan in the software. The controller supports the fan, and it's in your kit. The fan comes with very short wires, so you'll need a pair of extension wires to allow the fan to be on the extuder, powered by the controller. - Find four small M3 screws (just a bit longer than the fan's depth) and use them to attach the fan to the open end of the extruder body (two holes) and to the fan vent (the other two holes). - Then put the vents into the vent hole on the bottom of the extruder. It should be turned so that it aims towards the hot end. Note that the vent is angled 15 degrees away so that it doesn't get too hot. Note also that the vents are octagons, not round, so they can't be rotated - you have to remove them, turn to the desired position, and re-insert them. Then mount to the gantry. These are all the same as for QU-BD's parts. Or if you use the printed gantry mount, it's nearly the same but you snap the linear bearings into the clips without zip ties. - Use zip ties to hold two linear bearings onto the guides, per QU-BD's instructions. - Print and use the QU-BD belt clamp (http://www.thingiverse.com/thing:218670) and use it to hold the belt to the extruder. It attaches with two short M4 screws. The belt should not be on the gantry when you do this. QU-BD says to superglue the extruder to the belt, but this is much better. If you use the printed mounting plate, the grip is built into the design already. - Then slide the gantry rods into place (per QU-BD instructions). - Build the Y axis tensioner (washers and bearing). Instead of using QU-BD's washers (which are too small to work) print and use http://www.thingiverse.com/thing:220008 to sandwich the bearing. - Finally, put the belt onto the Y axis gear, then put the Y axis tensioner gear in place to make the belt taut. I found it easiest to put the tip in, then use a hex wrench to pull the bolt straight and screw it in. Use - To load filament, squeeze the lever down, holding the bottom of the extruder still so that the rods don't bend. This will push the bearing away from the extruder gear, so you can feed the filament down into the hot end. Push the filament between the gear and bearing, then into the hot end. Then release the lever, and the spring will push the bearing against the filament. To unload filament, do the same thing, but pull instead of push. If the extruder doesn't engage the filament strongly enough, you need to increase the spring tension. To do this, print Spacer1mm.stl and insert one (or more) at the bottom of the slot for the spring, until you have sufficient pressure to feed filament.

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Mar 12, 2016 - Modified Mar 12, 2016

Will this work with V2 parts? The idler bearing and spring are different sizes now. The spring is ~6.75mmOD, ~19mm tall. I cant measure the bearing at the moment.

I ask because I've printed several extruders, none of which fit with V2 parts.

Wondering along the same lines. I have a TwoUp v1 upgraded to a Threeup. Can anyone confirm whether this extruder will work?

I have to confess that I've stopped using my TwoUp, and so I've stopped upgrading these parts. If there's interest I could tweak the parts based on the measurements posted above and share them, but I can't test them. I'd also be happy handing the design to someone to go forward, if anyone is into TwoUp printers and (simple) OpenSCAD coding.

Did you change the design of the arm that has the bearing in it? I noticed the version I printed the bearing does not stick out past the plastic ad causes issue's with extruding when leverage is pressed against it forcing tension against the motor.

Great design, only issue is the parts dont fit together cleanly, even printed on a high resolution picture there were issues with the pieces fitting together flush

Will this work with e3d hotend?

The basic design should, but you'd need to adapt it to fit the mounting, which I don't believe is the same.

Great job. I have a one-up and cannot print the entire body or lever in one print. Any chance you could post each half of the body and lever separately? Alternatively, as I am new to this, is there a way for me to separate the parts in the stl file?

I don't know if you found this out, but you can open the part in "meshlab". Just import mesh, then select the verticies of one side and delete them, then export as lever 1 and repeat for the otherside naming it lever 2 or something. Worked for me.

Nov 4, 2014 - Modified Nov 4, 2014

Can this be printed in PLA or will it melt by staying in contact with the hot end?

BTW pink for the win lol!

Yeah, the TwoUp came with pink filament, so that's what I printed with. :-)

PLA starts getting soft at 60 c, so I'd go with ABS if you have the option. The extruder doesn't really get hot, since it's separated from the hot end by a few inches, and the fan should be blowing through it, so in theory it should work OK.

I don't have ABS... I'll see if I can find a solution by putting some material in between the hot end and the PLA parts.

The tube serves as a heat barrier between the extruder and the hot end, so it should be OK. Plenty of RepRap printers were made out of PLA, and some still are. If all you print is PLA, your temperatures are lower, so a PLA extruder should be OK.

OK so I'll try it straight as a first test, thank you for the info!

What bearing are you using for the idler? I tried my stock bearing, but the ID is a bit larger than the shaft on the lever and it just wobbles causing a misfeed, when I measure the part in netfabb I get ~9mm across, my bearing is a 3/8" X 5/8" X 5/32". Are my printed dimensions that far off?


Great job on the extruder. I was wondering about the upextruderv11-lever.stl part. In the overview it shows a right and left side of the lever, When I print this part all I get is the right side, and what looks like a pin. Even the preview shows the right and left side, but after I run it through the slicer I end up with a pin and the right side of the lever. Have you seen this? what do I need to do to get the left side printed?

It sounds like you're printing one of the two parts, and the other one is off the side of the print area. You might need to center the part in your slicer so that you can see both halves.

What printer and software are you using?

I've got the TwoUp with the standard board, I'm using Repetier with the built in slicer. I centered the parts on my work area before slicing. I'll try to move it over some more. Thanks for getting back to me so fast.

If that doesn't work, I can separate the two levers into separate files.

laird, I got it to work, using a different slicing engine. Thanks for your help.

That might work, 'cause moving the left half toward the center of the work area didn't work.

Hello laird, I really like your replacement extruder and I have it mounted on my Two Up. However, the only way I could seem to mount the vent with the mounting square was on the left of the extruder with the lever on the right. The mounting square needs to be on the other side of the vent to mount it on the right at the back of the extruder or have a large whole in it for the motor if mounting on the front of the extruder. Is there a simple way to print the vent and mounting square for use on the right side of the extruder?

The extruder is symmetrical, so you can mount it with the lever on either side. I use it with the lever on the right, which gives you the most print area, but it requires you to reverse the direction of the motor in your firmware settings. If the lever is on the left, it hits the Z axis rod reducing print area a bit, though then you don't need to reconfigure the firmware.

I'm not entirely sure what you mean by 'mounting square'.

Thanks for your work. I think I have the same issue justinSmithChi did; my bearing has an ID of 9.5 mm and OD of 15.9 mm. It's a little loose on the level and it can't reach the extruder gear. The looseness may be partially due to under-extrusion but the "stub" is only 8.4 mm. In the STL it appears to be 8.7 mm, which is still quite shy of 9.5. Are we using different bearings?

I increased the clearance with the lever, as theres an outer guide that can prevent the lever from pressing against the gear. Print the new lever, the bearing should reach the gear.

If this doesn't work for you, can you take a picture?

I've got this whole thing printed and assembled on a two-up, but there's a pretty large gap between the bearing and the feeding gear - so much so that it won't actually feed the filament in. I see that your bearing actually overhangs the sides of the circular piece on the lever that holds it - mine definitely doesn't. Any ideas?

If there's a gap between the bearing and the gear on the motor, is the lever up all the way? If not, pull the lever up. Does it engage the filament properly then? If so, then the issue is that the lever isn't going up all the way, in which case either you need to use a spacer or two to move the spring up higher, or the screws through the lever are too tight, causing it not to be able to move.

If pulling the lever up doesn't engage the filament, the second thing I can think of is that the bearing holder now has a wider rim, which someone suggested, as a means of guiding the filament to the hot end. That outer rim is designed so that it should be cut out to fit around the gear. Is that outer rim keeping the bearing from getting close enough to the bearing to engage the filament? If so, please let me know - it fits on mine, but it's pretty tight, and perhaps with variations between printers printing the parts, it's too tight a tolerance. I can easily add another 0.5mm of "gap" and re-upload. Would that do the trick?

If those aren't it, I'm not too sure what's going on. Can you post a picture?

I ended up sanding down the pieces of the disc used to guide the filament so that it could get a little closer to the gear, and that did the trick. Now if I can just get past Repetier I may be good to go! The Makerbot at my office spoiled me.

Excellent! I'll add a little more clearance for future prints!

Repetier actually works pretty well. It's not as slick as MakerWare, obviously, but it works fine. And in some ways I like it better - it's great (in a techie way) seeing the heat curve, and when the heater is on/off, and the head movements, the detailed status back, etc.

What are you having trouble with? Do you have it connecting at all?

Hi. It appears one of the files is missing --- ie. UpExtruderVent9a Are you currently making revisions?

It's there. Can you try downloading again? Perhaps Thingiverse or S3 had a temporary issue?

I printed this today, looks really good and hope I get it on the printer soon. It seems the UpExtruderVent9a is a bit loose fitting in the octagon shaped hole in the bottom of the extruder. I wonder if the sizing is off? The width as shown on the build plate was 11.05mm. And what should the total length be? Thanks.

I put a loop of tape around the top. I'll make it a tiny bit larger to fit more tightly.


This works perfectly with the printed mount plate (http://www.thingiverse.com/thing:223327)http://www.thingiverse.com/thi.... I added a few photos of the two parts together.

Qu-bd Oneup / Twoup Bearing holder for extruder
by lonuf

V5 Update:

  • Made lever much stronger. If you're using v4, print the v5 lever and swap it in. The other parts are unchanged.

  • Generated all of the individual parts, and plates of pairs, in addition to the plate of all parts, so you can pick which you want to print. So you can print just the new lever! :-)

I like the changes but not sure about the vents. I would prob mount my fan pointing directly at the nozzle to cool the plastic as soon as it leaves the extruder.
These 40mm fans dont cost alot so you could easily build 2x 40mm fans into the design so one is cooling your print and the other can be added to blow into the extruder for the motor and to make sure the heat doesn't creep too high up the filament from the hot end.
Not a big fan of small vents and nozzles, I much prefer direct airflow.

Great work with all this, its pretty darn impressive and very helpful to those of us who are missing parts.


Yeah, the venting is an experiment. If you don't like 'em you can just leave the vents off, and the extruder is fine. Remember, QU-BD ships the printer with the fan disabled by default, and that's how I've been printing so far (until I get around to re-flashing the firmware). I'm mainly adding the fan and venting to the extruder design because I want to try it.

Hey, what do you think of this idea - attach the fan to the right side of the extruder, hanging below and angled down at 45 degrees? Perhaps I'll add it...

I might try it first with the vents attached as they carry a fair amount of air flow (more than I expected). I will let you know how it goes. V4 is printed and ready for a little clean up with my trusty ceramic bladed work finisher to remove a few bumps and burrs and then I will put it all together, attach to my 1up and take it for a spin!
Will report back with some photos later...

Great work, this is a fantastic design!!! Would also make a really awesome torture test as it has a little bit of everything from hollow boxes and tubes, to overhangs and some tight fitting spots that need precision to get it right.

Thanks! Please post some pictures, if you don't mind - I'd love to see how it fits on your printer.

Yeah, it's a fairly tough print. In v4 I made it a bit more forgiving, but there are plenty of 45 degree angles, and some bridging, so I had to dial speed way down (40 mm/s, old school!) to get it to print well for me.

I didn't have any trouble with the angles and bridges, printed in ABS at 150mm/s on my RXL - which usually does have lots of trouble with that kind of thing. The only imperfections were a tiny bit of stringing in the rectangular fan inlet piece, and the final ten or so layers were lost due to a last-minute extruder clog (didn't adversely affect assembly thanks to the mating ridges you added). I was mostly worried about the venting tubes, but they printed absolutely perfectly.

That's very cool. I look forward to seeing the result! Mine is working great for me now, which is quite satisfying.

Printed a bunch of pictures. They pretty much show the assembly in order.

Minor update: I got the 'plated' version properly leveled - a few of the parts were 1mm off, which of coursed caused them not to print properly. Oops!

Last version was a little buggy but did fit and work (un-attached to printer).

Will give this latest version a try. A reel of Taulman Nylon and one of some really nice ABS just arrived so will give it a try with one of those and also make sure my RepRap is all calibrated perfectly as its been a while and I think the Z height is off slightly due to the bed dropping a little.
Will print a test in PLA first and put it all together and post again.

Nice. I just updated the design a bit. The main changes:

  • Angled the vent a bit so it's further from the hot end (so it doesn't melt)
  • Added some guides so the top/bottom halves are held in alignment when assembled.

Updated with:

  • The big change is that I Integrated the cooling fan into the extruder. It blows air into the extruder gear to keep it cool (the motor generates heat), and also blows air down onto the print.
  • Numerous small changes so the fit with the hot end is tighter, the spring is held in place, the screws are easier to insert, etc.

Running this off now and will try it on my 1up and feedback.

Let me know how it works out. I'm continuing to make changes, so I'll be posting updates.

Very cool. At least hopefully. :-)