Remote Direct Extruder with Bondtech Gears (30:1 Gear Ratio)

by fredator Nov 30, 2019
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Dude. Wicked. Well done. Any chance of making a Sidewinder version?

Do you know how long i need to cut the ptfe tube connecting extruder to the hot end?

It depends on your flexible shaft. I have cut mine as long as is round part of shaft. There is no huge torque, so there should be visible 1cm of square end at every side and you are good.

i mean how long is the bit of ptfe tube for filament from the output of the extruder to the nozzle bit?

It depends on your hotend. If you are using e3d v6 right under this extruder, it is 38mm. Just measure depth of your Hotend and add 3mm to insert it into extruder. You can look at my remixed head for Hypercube to see my solution. https://www.thingiverse.com/thing:4151649

Hypercube evolution - remote direct drive head
by Kotvic


What is your stance on some multiplication gear set at motor side? Through gears or belt. It would allow to solve current motor speed and noise issues. And may be even allow to go 40:1 or higher to decrease torsional flex problem of flexible shaft. Flex shaft can spin at crazy high rpms, but not good for high torques.

Thank you for this little masterpiece.
I am printing last few pieces for this extruder and cannot wait to test it on my Hypercube (remix in progress, need to try it before sharing).

I have one question. It is D slot meant only for bondtech gear and EXTRUDER_Gear is friction fit?

You are talking about D slot on 5mm shaft, but there is round hole in EXTRUDER_Gear. I think, that D slot in EXTRUDER_Gear will be little bit better option for long run.

i friction fitted the front bondtach gear, the one on the door, it spins freely when the door is open.
The inner gear has a grub screw calming it down the the shaft.
Mine is still untested as i am waiting on parts to arrive from aliexpress

Thank you for your reply. Bondtech gears don`t bothers me. I am afraid that friction fitted printed gear can start slipping after a while. If there will be D-slot along whole 5mm shaft, there can be D-slot in printed gear and this connection should provide longer service life for printed gear.

i friction fitted the printed gear and added a few spots of superglue. The fitting is very tight. I didn't make any D cuts in the shaft as in my brain i want it balanced as much as possible (i know it will make no difference) When/if you cut a d slot just do it where the bontech gear would go.

Very good job fredator, thank you for sharing the CAD files.

I'm going to modified for my printer.

I have a zesty V1, I am going to try to adapt this to use Zesty parts but convert to Bondtech, wish me luck. Looking to print TPU

Cool design, seem a few of this kind of thing, have decided to try yours as it sticks out the front allowing for max print size in the z (wont crash the top bar)

What are the cheap clones called on aliexpress for the gears?

"Bondtech gears (1.75mm/5mm version) or some Btech clones"

Do i just buy a clone extruder and pull it apart? What do i search for in aliexpres?

Thanks :-)
You may check out the clones made by Trianglelab or Mellow Store on aliexpress.
I tried only original Bondtech and Trianglelab's knockoffs.

Thanks. One thing i can't find is "1m of PA12 pneumatic tube (4/6mm)" does it go by other names? or do you have a link to it online somewhere?


Printing mine all in black and so far it looks awesome. I am not sure how long my worm and gear will last in eSun PLA+

The first time i ordered the tube locally. Second time - on aliexpress and it's ok but, the shop disappeared so I can't provide the hyperlink now. I suppose this one should be ok - click

You can also search aliexpress for "pa12 pneumatic tube 4/6". There are several results :-)


Nice work, think i‘ll put this to my shopping list.
I noticed zesty reduced the gear ratio to 1:20 in their v2 nimble, could you adapt this as optional part?

Thanks :-)
I'm currently testing 10:1 worm gear ratio (should solve the problem with 8-bit boards by lowering the e-steps value).
I'll consider adding 20:1 ratio too.

Hi, Do you plan on doing a 3mm version with the bondtech gears (ID 8mm) ?

It would be hard to make such a change and support it without having the 3mm/8mm version of the gears. Honestly it would require a pretty substantial changes in the project.

Hi. I'm currently testing your extruder but I'm not sure how to set microstep and motor current. For now without changing those settings the extruder motor misses steps a lot.

It depends on what motherboard, stepsticks and motors do you have. Please provide some specs, and I'll try to help you.

I'm using stock v1.1.4 motherboard with A4988 drivers and stock motors. Basically all stock Ender 3 Pro.

Ok, AFAIK there is no way to change microstepping in stock motherboard without soldering. If you find the exruder e-step value too high for you 8-bit mobo you may try using a multiplying gearbox on the stepper motor side.

But for now, if you have problems with loosing steps, you may try changing your vref value with a mobo potentiometer to about 0,3V (for extruder) and adding this gcode to the "start gcode" section in your slicer:

M201 E30.00 ;Set maximum extruder acceleration (mm/s2)
M203 E20.00 ;Set maximum extruder speed (mm/s)
M204 R30.00 ;Set retract acceleration (mm/s2)
M205 E0.6 ;Set maximum extruder jerk (mm/s)
M900 K0 ;Set K-factor;Remote Direct configuration

You may also reduce these retraction/jerk values. The idea is to find some working (without loosing steps) parameters and then try to tune them with the guide in project description.

There is already an advanced project using this cheap worm gears:

You may want to check this out :-)

el'wał - extruder with flex shaft (like Zesty Nimble one)

Amazing work!!! Any chance to get the STEP/SOLIDWORKS file?

Incredible nice work! Thanks!

I am new to 3d stuff and currently banging my face against the keyboard learning fusion360 :)
I would like to make two changes: make it compatible with duet smart effector and add a direct mounted nema8 stepper.
Gear ratio 30:1 is perfect for nema8's low torque, may be 20:1 could work also. This would make the extruder less or maybe just around 100g but a lot more precise by eliminating the backlash of the flexible shaft. though, a flex shaft has less mass, but it has spring-resistance on bending, this is why i got rid of zesty nimble.
Can take a while, i just spent 30 minutes to get four holes into a square thing (what should get a mounting plate i am trying to make) xD

I agree about the backlash of the spring cable especially since this is a single twist cable, the one zesty uses is a dual opposing twist so it has equal torque and very little backlash in both rotational directions. I do like the idea of the nema8 sitting on top, I have a few nema11's from a old project I've been considering using in some way, this may be an avenue....


I just uploaded thing 4081130 which is a remix of this kit to mount a NEMA 8 for direct drive

Wow, you guys are awesome! i am still biting through a bunch of tutorials xD

You are welcome :-)
Modifying this extruder to use NEMA8 instead of flexi shaft would be a very interesting project and may be challenging too. If you manage to make such a design and publish it with some nice descrpition on thingiverse I will test it out for sure!
I'd appreciate it if you published it as a remix of my project :-)

Good luck!

This is close to my plan. I have the NEMA8 x40mm Motor (80g) and the bondtech gears already lieing on the desk. The gear ratio I calculated is 1:11. That takes into account the losses in a straight gear. A worm gear is much less efficient.

Can you provide some hyperlink to this motor description/supplier?

It is from Nanotec type ST2018M0804-A
Not the cheapest, but well documented. With 24V supply it can go to 3000 rpm.

Indeed a very powerful nema 8. But if you say you want a strait gear, maybe nema8 is not the ideal motor? nema 8 is perfect for wormgear as a toploader, because of 20x20mm footprint in a narrow environment (like delta effectors).
for straight gear a pankake is probably a better choice. the torque of a motor is relative to its diameter, that is why nema 8 are so weak.
this one has more diametr, but only 9.6mm "length" and a torque of 6ncm at only 15gramms more: https://de.nanotec.com/produkte/565-st6318f1004-a/

This one is much more powerfull indeed. I have to admit that I only searched for NEMA8, with the idea that there is a choice of different length motors to optimise weight and power later.

Would this be compatible with an e3d v6? Any ETA on an adapter fit for something like an ender 3?

I‘m currently working on a remix to fit this Extruder to my Prusa Bear - Ender3 Heavy Duty Mount Mix which I‘m using right now. When I‘m done with it I may consider to upload it as a remix, but there are quite a few parts I don’t like yet. The remote direct drive is a bit thin walled and so would like to have a more rigid idler door.

I can say that it almost certainly won't fit on any existing ender 3 v6 mount. Using the minimalist mount (https://www.thingiverse.com/thing:3393889) you might be able to only have to slightly modify the current ender 3 mount.

Edit: I think you might be able to not modify it at all if you used this mount

E3D Minimalist for V6 & Volcano on Creality CR10/S Ender 3/Pro and clones

I'm afraid the existing Ender 3 mount won't be compatible with E3D V6. It's very likely I'll create such a mount (because i have V6 somewhere in my drawer) but I don't thing it will happen in near future, because I'm focued on some different parts of the project now.

I can say that it almost certainly won't fit on any existing ender 3 v6 mount. Using the minimalist mount (https://www.thingiverse.com/thing:3393889) you might be able to only have to slightly modify the current ender 3 mount.

E3D Minimalist for V6 & Volcano on Creality CR10/S Ender 3/Pro and clones

Great idea. I had a thought of a remote motor drive direct extruder and stumbled upon this thing posted on thingiverse. Looks like you have done all the hard work. Thumbs up!

Thanks, I did my best :-)

Hi! I love this idea! Can you share any data you may have about the performance? I'm interested to know specifically how retraction works with this set up. Does the flexible shaft introduce torsional flex, and if so, how did you compensate? Step adjustment? Thanks!

Hi RumBot,
I'll share some performance data soon. Are you interested in something specific in case of retraction? During my test it was set to 1mm@20mm/s and worked pretty well.
The shaft introduces torsional flex - about 1/4 of flexi shaft turn, what makes about 0,19mm of play in filament feedrate (thanks to 30:1 gear ratio). It's not a big deal in case of retraction IMHO, because you can always set the retraction distance a little bit longer.
It may be problematic in case of Linear Advance, because the retraction move is long and pretty slow (Bowden system doesn't like LA too, it should be better in case of remote direct, but we'll see).
If there only was something like extruder backslash compensation in Marlin (it is there for X, Y and Z axles) it would be worth testing it.

Incredible :) I published a similar design exactly 3 days ago. Nice work:)
I'm curios about your print quality. With mine I see some minor inconsistent flow effects. I don't know yet the root cause, my imperfect printed gear-set or the flexible shaft wobbles.
I decided to use 10:1 gear ratio insted of the 30:1 because with that high ratio I had to slow down the acceleration of the extruder too much reducing the total acceleration of my printer. You have an aditional 3:1 gearing ratio betwen the wormgear wheel and the BMG gearset. How the 30:1 gear ratio works for you? I have not really printed with that option yet.

Hi Robert,
I think both 30:1 and 10:1 gear ratios have their pros and cons. It's always some kind of compromise between ease of retraction parameters
setup on one side (low gear ratio) and lower play and cariage twisting/vibrations on the other side (high gear ratio).
I decided to choose 30:1 GR and use multiplying gearbox in case of low retraction speed/acc. It should combine advantages of both approaches, but I plan to test lower GR's too.
Inconsistent flow may be caused by seam on the worm, bearings on the worm not perfectly parallel, some play on shaft/bearings, active btech gear eccentricity and much more for sure :-)

Nice job with your project BTW!

Thank's for your opinions :). I made some improvement in the meantime the print quality improved. I have enveloped the flexible driveshaft in a 4mm rubber shrink tube. Shrink-ed on the shaft with hot air. Now the thickness is 3.6mm. Lubed the whole assembly with low viscosity grease. Now the shaft do not wobble anymore and is also its stiffer than before. At this point this is the best extruder I ever had on my printer.

you are not alone

And many more have been tried, even published, in the past, here and at other places.
So typical. An idea seems fantastic, is praised, tried then reality strikes ! It fades away to be "reinvented" and the cycle repeats ! :)

See the Zesty Nimble, has been around for years. It is maybe the finest, yet not that much success.

Great work! What about the pulley? :-)

Great work! is there any chance you could release step files for CAD? my Inventor can't open your CAD files. Which is weird since Autodesk made both programs.

If you get Autodesk Fusion 360, (which is free), you can import the .f3d files to fusion and then export inventor files from Fusion.

I understand that, but I use a different program and I'm not going to install F360 just to convert these files. If OP releases step files they will be universal for any 3d modeling program.

I see. I was basically just pointing out that it can be done, if you are impatient like me ;)

I can also import .STL files in inventor, but then you lose resolution. Round parts become a bunch of flat surfaces.

Yes, in next release of new files I'll export STEP files instead of F3D.

Nice job. Thanks for your hard work.

You are welcome :-)

What a good idea, I like it when people explain their projects very well, hopefully we'll see improved versions of this concept and not be left aside ... this is the way! Thanks fredator!

Thanks, I did my best :-)
It took me some time to prepare it. If you have some suggestions or found some mistakes please let me know.

Why did you use printed worm instead of metal one? e.g. http://aliexpress.com/item/32931426752.html

These are heavier and lauder.

Szendo,I did that allready. Metal ones are heavier. Project started 1-2019, is on hold due to time problems as new DIY CORE XYZ printer is more important.. 30 teeth gear is 4mm diameter and you need 5mm axle for BMG alike gears. 40 teeth gear is 5mm but gives you higher ratio. Fredator is a few steps ahead and delivered a nice job. Will try his solution too. Maybe I mix it :-) Keep thinkering guys.

Thanks for explanation and I hope you make it and give some feedback after that ;-)

EDIT: Ahh and I forgot to mention that you did a great job with your extruder. Do you consider sharing it?

When I complete my DIY CORE XYZ pprinter the extruder will be shared for sure.
I found this new entry too.............we are not alone.
Keep up the good work.


Remote Direct Extruder with Dual drive gear-set

Nice job and extensive explanation.

Wow! Just wow. I was surprised at the lack of comments on this thing until I noticed it was published 7 hours ago. Absolutely incredible job! I have been searching casually for a Zesty Nimble alternative for a little while, and this is absolutely amazing! I can't wait to see what people do with this.

As a side note, what settings did you use for your setup? I also have an Ender 3, and I am unsure as to what settings to use. Also- where do you set E-steps per millimeter? In Cura? Do you have to upload Marlin and change the settings there? I am new to software stuff with 3d printers, though I have been intending to upgrade my software for quite some time.

Again, absolutely amazing work on this. It completely blew my mind!

Thanks a lot, I'm glad you like it :-)
This project is still beeing developed - if you make it and give some feedback it would be very helpful.

Here are my settings:
;Remote Direct configuration
M92 E4268.00 ;Set steps per mm
M201 E120.00 ;Set maximum extruder acceleration (mm/s2)
M203 E20.00 ;Set maximum extruder speed (mm/s)
M204 R120.00 ;Set retract acceleration (mm/s2)
M205 E0.6 ;Set maximum extruder jerk (mm/s)
M900 K0.3 ;Set K-factor;Remote Direct configuration

They are added in my slicer's starting gcode. It is handy to use serial USB connection (Octoprint in my case) to calibrate these settings first time. There are some limits of Ender's 3 default Marlin setup (lack of Linear Advance, no thermal runaway protection, etc.), but i don't think it is mandatory to install bootloader and upload Marlin for this upgrade.

It appears as though your settings are duplicated- is there a reason for that? M92, M201, M203, M204, M205, and M900 are in the first half, and then they repeat in the second half with identical settings. Is this a mistake?

Yes I pasted it twice by mistake. Sorry for that.


Good luck and Happy Holidays!

hmmm maybe I could order those gears to be printed in SLA :O
but damn great job! this is great

When you use such a gear ratio, you can use a smaller motor like a NEMA14 and in fact mount it directly, no flexible shaft and get down to 180g for a direct extruder plus hot end !

BTW 30:1 is too much ! The stepper will likely not follow for high speed retraction unless powered by 24V !

You can use a direct drive extruder with NEMA14 but honestly 180g is a lot. My extruder weights about 70g (including half of PA12 tube and half of the flexible shaft). Without the tube and the shaft it weights about 45g (it's 20g more than Zesty Nimble) what IMHO is a good result for a dual drive system.

Indeed 30:1 is a lot. My power supply is 24V and it can be used with 20mm/s retraction speed. In case of 12V PSU you can always use a multiplying gearbox.

Higher gear ratio gives you lower error in case of flexible shaft distortion.

180g is ALL included, and the total moving mass including the carriage is 220g .

Besides, with your flexible, it is not just a matter of mass !

I tried what you just did, 3 years ago and was not satisfied.

In fact, the Zesty and others are not used much.

And don't speak about accuracy, this IS NOT accurate. It is FLEXIBLE ! Anyway accuracy is enough and somewhat irrelevant.

Fact this system is no better than a simpler Bowden.

Improve it if you can. But surely you are not one of those who succeed...

How about YOU MAKE IT and come back with the results ?

I have no time to waste !

You cn also try this one:


Remote Direct Extruder with Dual drive gear-set

MKSA why are your comments so rude? If you don't like the idea than don't use it. Otherwise come with constructive feedback please!

I tried to reply to your previous message couple of times but thingiverse is blocking it with message "This comment is currently flagged for moderation.".

Maybe it was too long, if this one will not be blocked I will answer you again after coming back home.

I'm glad you raised the subject, but be a little more precise, please. It's hard to compare two solutions when specs of one of them are not known.

  1. By "ALL" you mean the extruder, motor, hotend (V6? Creality?), hotend fan, blower and a mount?
  2. Could you provide some photos/project page of the extruder you are talking about?
  3. Could you provide some specs/photos of the solution you tested 3 years ago and were not satisfied with?

In regard to accuracy it's not the same as bowden IMHO. In Bowden system you can do nothing with the filament elasticity except
using 3mm filament instead of 1.75 or trying to make bowden tube less extensible. In case of flexible shaft you can decrease the error caused by
its distortion with gear ratio. In fact the shaft I used there is about a quarter of revolution of "inertia" and because of 30:1 gear ratio it gives
about 0.19mm of filament feedrate error. Try to compare it to Bowden where in case of retraction you need to set the retraction distance about 3mm more
then in direct drive system (Ender 3 example) what means it has an error of about 3mm using 40mm bowden tube
(may be a little bit less with 1.9mm inner diameter tube).

Bowden is lighter and simpler - I agree, but retraction callibration is a way easier with remote direct.
The first time I mounted my extruder there was close to no stringing at all with
1mm retraction distance @ 20mm/s retraction speed using PET-G filament without part cooling fan. Try to achieve it with bowden.

I agree. bowden has its own issues. I was never able to get decent print quality over 70mm/s. With an approach like this I got much better result and printing with 200mm/s. Below 50mm/s my bowden setup gave me better result.

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