Flex3drive Gen3

3D Printing Club ~ 3DPC.tech 

Developed over several small run iterations by a relatively tiny company, the Flex3drive has all the hallmarks of an insane idea that should fail in almost every way one can think of.

The concept is out of the box to say the least, a shaft driven extruder allowing for direct feed in to the hot end but keeping the stepper located remotely to save on weight.

This has been attempted before but to limited success, for some time the idea of remote drive extruders were scoffed at and with good reason, cable drive is often plagued by backlash due to drive cable flex and twist. They just can not be used for applications that need precision under torsion.

The Flex3drive solves this by a solution so simple it is almost poetic, gear ratios. Gearing down. You not only mitigate the effects of extraneous twisting and flexing, you also gain extra torque without putting more stress on the drive cable.


Well, it is fair to say that the package contains everything, up to and including the kitchen sink. This really is an insane amount of extras.


Also included (pictured here and further above) Spare lever arm, motor mount for 20×20 frames and even a coupling to hold the XL bowden that carries the cable drive.

You seldom get so much stuff bundled in with hardware like an extruder, we have optional cables, drive cables, PTFE cable shields, motor mounts, coupler shields and couplers, spare load arms. This really is an impressive array of extras.


First Impressions and set-up

For such a compact extruder the overall design and construction are fairly complicated. The principal being used to provide drive is a simple one, but refined to the Nth degree over multiple iterations.

Installation of the hotend could benefit from being simplified slightly as you must tear down the entire assembly to access the bolts that hold the hot end mount in place, but it sure is secure.


Just look at these bearings, parts quality really is top notch.


This design forgoes a spring arm in favor of a double lever, offering consistent pressure.

Overall, the assembly is compact and very light, coming in at 57 grams not including the E3D.


The built in mounting points are perfect for this particular installation, although seeing a variation with the mounting points added to allow for the extruder to be installed on a vertical carriage would be a nice extra to offer.

Note, whilst you can set up your microsteps, steps per unit, acceleration and jerk however you want, there are some recommended settings it is worth trying to get you started.


Print Quality

For these prints we are going to ignore line segments and other poly related artifacts as they are not direct products of the extruder. We are going to look at layer adhesion, handing, consistency of width (sometimes called pulsing) and surface finish.


Such consistent flow, absolutely no pulsing and wonderful quality over difficult curvature (These heads are apparently optimized for vase mode…. The hole in the nose says I disagree) The overall. Printed in 0.2 height at 150mm/s. The layering is virtually perfect even when extruding at high speeds.


Same model as earlier, printed as solid 10% infil 0.1mm layers, 150mm/s. I really can not describe how nice this looks in person, Images really do not do it justice.


The above image represents aprox <26mm> Extrusion is so consistent (I keep saying that) That you can just about make (if you look really )out the pattern of microsteps from the X and Y motors. Be it a Benchy, cube, tower or a Minion The results are consistently fantastic.


Quite some time ago, when what is now the Flex3drive was just an idea bouncing around print enthusiast pages I lambasted the very notion of a remote driven direct extruder as being far too impractical to implement and even then far too potential buggy.

I was wrong, oh boy was I wrong.

Aside from some aspects of setup and assembly being slightly fiddly, this may be the best extruder I have ever used. It just works, feed this whatever you like and it will just work and come back for more and loading filament is a dream come true.

You would not believe that such a refined extruder would be produced by such a modest sized company as Flex3drive. The big boys have a lot of catching up to do, this is light years ahead in terms of execution.

Setup is somewhat arduous but once set it will pretty much run anything you put in it.

Installing the hot end itself onto the bottom of the extruder is quite the headache, as previously noted, you must dismantle the entire extruder assembly to access the bolts holding the hot end mount, the saving grace is that despite being semi complicated, the parts fit together so well that reassembly is almost idiot proof.


  • Light weight
  • Reasonable price point
  • Solid design and construction
  • Compatible with 99% of filaments
  • Reliable
  • Great post sales support



  • The only way to remove the hot end is to dismantle the whole extruder
  • Set up whilst essentially “one time” is more arduous than most extruders


Final thoughts

This is a great extruder that I would be comfortable using on any of my machines, precise, strong and reliable. The pros far outweigh the cons and even then the cons are nitpicks.

I hope a future design offers an easier way to remove hot ends and that additional mount options or even a mount dock can be offered

Is it worth the money? The honest fact is that this is cheaper than some of the high end extruders available and leaves them all in the dust. Yes it is absolutely worth the money.

Enjoy issue free printing with incredibly step resolution and smoothness.



Thanks to Flex3Drive for providing us with a Gen3 unit for review.

Reviewed by Toby K for 3DPC

Printed on the Horizon 2.0 core XY


Genius, Billionaire, Playboy, Philanthropist, Founder member of the Avengers...... Hang on.. That "may" by Tony Stark. Modder, Reviewer, Maniac, Designer, Builder, Reader of any books, Lover of steak. The Mod Zoo and 3dpc founder member.

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