Compact Bowden Extruder, 1.75mm Filament for MK7 Drive Gear

by Tech2C Apr 12, 2015
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For everyone who's idler has snapped of at the bearing post over time, pay attention to the flat spot on the side of the .stl file. The idler is supposed to be printed on its side to prevent this issue.

Will a standard mk8 gear work the non hobbed version?

I've now printed out 2 of these and both have broke.
The bearing holder just snaps off eventually.
Also, when using TPU there's too much of an unsupported gap and the filament tends to double back.

Anyone tried this with ninjaflex?
Printing right now and going test flexi filament

Can you upload the new reverse version of this that you are using in new hypercube videos the orientation is opposite due to where it is mounted on the back corner. It would be appreciated!!!

No need. Simply mirror it in the Y axis within your slicing software.

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Quick Question. I printed this out for another printer, but needed to use it on my current one to print a broken piece. On the normal settings, it just clicks once the filament reaches the nozzle. If I turn up the pot a little bit, it extrudes but then overheats and the motor stops. Any ideas?

This bowden extruder can print flexible filament with no problems??????

I don't have the z axis support but instead have a acrylic support that came with my kit. How would i mount the extruder mount?

I have a Rework I3 and printed this in PLA because I am having a terrible time dialing in my ABS printing. Any comments/concerns using PLA vs. ABS for this design? I assume I will eventually have to make them ABS.

i also wish to know, i am in the same situation, though i have figured out i think my ABS issues id heat control and i may have to enclose my printer, seems no matter what else i try i get warping even on small parts.

I think I had layer issues. I upgraded to lead screws, I hope that solves issue, haven't tried reprinting ABS yet. I'm going to a bowden setup too.

Hello guy. First of all congratulations for your channel. I enrolled for a year now and I'll follow with admiration and draw inspiration from your ideas for my projects.
I saw this change for my reprap, printed and assembled it all, but as you can see from my video bearing slide on the wire. for this I applied a bit of tape, but the problem persists. how can I overcome this?

So far I'm very impressed with this setup. I love this design compared to the others I was trying out. There's just one problem that I have, and it's something I decided to note here for others' reference:

If you are like me and have to print this in PLA (because you need a good solid enclosure for ABS, but don't have one yet), be VERY careful when adjusting the tension on your idler. If you over-tension it, you'll have really good prints and a solid grip......for about 4 hours at most. At that point, the bearing mount will snap off partially, which gives the appearance of being attached, but you lose all tension and ruin a 6-hour print in the process. Proper tension and spacing is important. You don't need much, just enough.

works great ! simple and easy thank you sir

Hi tech2c can you tell me if it can work with 11,8mm drive grear ? I just finish to mount it but it look to be a little bit to big filament is not straight my are like this but 11,8 https://www.aliexpress.com/item/Wholesale-2pcs-lot-Makerbot-MK7-MK8-Drive-Gear-Reprap-Extruder-Prusa-i3-Impressora-3D-Printer-Part/32249229301.html

I have original drive gear from my rework 1.5 but look to small... So the other one I have mounted is coming from alyexpress metal extrudeur makerbot who was a crapp ! Motor was not able to push filament or extruder eated it ! So I want to reuse the drive gear to test your simple extruder.

I also tryed a bowden l3k but I get a lot of oozing I think because I m limited to 40mm/s retract speed and gear reduce a lot the real retract speed ... so I wanna test your before going back to direct drive ..

What is the thread on that pushfit? I have one threaded with an m6 threaded pushfit

You've drawn over the screw hole, so I can't insert a screw. Can you edit it?

You should not need one, in the video , he only uses 3

Either way it doesn't look very neat, so I would prefer it to be either accesible, or just completely removed.

Hi thanks for sharing it.
But can you explain or point me out how to calibrate retraction?

Keep getting under extrusion missing layers and so on?


Did you use a tap to get the push fitting in? It WILL NOT thread in and self tap.

I printed mine in ABS. It WILL thread in and self tap... :P

I'm brand new to 3D printing and bought a RepRap Prusa i3 kit. Got it working pretty good and now time to correct some of the minor deficiencies. I'm following your lead and bought an E3D V6, and am trying to somewhat duplicate your rig. I just wanted to thank you for your concise videos,and great instructions. I have everything printed and ready to go,just waiting on some Misumi bearings. Might as well go all out. Your troubleshooting and ability to adapt and overcome are notable and your videos really gave me the confidence to take on the project. Thanks. Keep it coming. It's appreciated.

Thanks for the feedback! Congrats on your new printer kit!

Only the idler is in the .scad file, is that the only thing that's different from the original? Reason I ask is I am currently using the original with an MK8 and didn't know if I needed to print the main part again.

What spring is a everyone using? Any links or specs?

Could you make a version of this for a 9mm pushfit connector? I have been trying to mess with openscad and I'm just totally lost.

Very good tutorial ! I'm about to apply the same change (direct to bowden) to My prusa I3 :)



where couid i get the jhead Mount you are using?

Ok got it, it shown in the Video ;)

Do you know how can i fix this in a Graber i3?

where i find the ptfe injector?

I bought these http://reprapworld.com/?products_details&products_id/169/cPath/1616_1653#.VeRXrPbtlBc , but the thread is too big . Is there a way to edit the file in such a way to use them ?

May I have the component list?? thank~~

Check the "Instructions" tab.

What did you change on the firmware when you switched to the bowden?

Take a look at the YouTube video. Thx.

Hi, Is it possible to use this set up for 3mm filament as well?

I'd say no, because pushing 3mm filament down a 0.4mm nozzle takes a lot more force than 1.75mm filament. You'd need to gear it down to gain torque for a 3mm Bowden setup.


Are you still using this design successfully ? I ask as I have a MK7 drive gear sitting idle.


He recently did a video on using flexible filaments with this, so he is using it quite successfully I'd say


Thank you for the link, I've now subscribed to his channel.

Is it possible to adapt your extruder for mk8 drive gear ?
Thanks for your answer

This is a Remix. If you visit the original designer of this part he describes how you can adjust the scad file to your needs.
But yes, you can certainly adjust the extruder to accept a MK8 drive gear. I did it for mine but switched back to MK7.


when you said adjust, you mean redesign or just do some tweaking itself after printing?

This thing need less space (on air) in path between gear and holder of bowden.. same as in original thing..

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