Itty Bitty Double FLEX V2 Extruder (With mount for MakerFarm Printers)

by clough42, published

Itty Bitty Double FLEX V2 Extruder (With mount for MakerFarm Printers) by clough42 Dec 30, 2015
10 Share
Download All Files

Thing Apps Enabled

Order This Printed View All Apps


A part of these Groups

View All

Use This Project

Give a Shout Out

If you print this Thing and display it in public proudly give attribution by printing and displaying this tag.

Print Thing Tag

Thing Statistics

15833Views 2798Downloads Found in 3D Printer Extruders


This is the third evolution of the Itty Bitty Double Extruder.

NOTICE: Version 2.1 released. See notes below.

A hardware kit is available; links below.

New in this version

  • Better flexible filament control
  • Supports Hexagon AO
  • Designed for easier printability with less cleanup
  • Low-profile shelf brackets to support underslung X endstops
  • Support for more Z probe switch types

Key Features

  • Designed for Hexagon or E3Dv6 hot ends on 27mm centers
  • Short, straight filament path to accommodate flexible materials
  • Uses the same hardware kit as all Itty Bitty Double Extruders
  • NEMA 14 motors
  • Silent GT2 belt drives with printed pulleys
  • Integrated servo Z probe
  • Cam-lock idler bearing pins
  • Uses our custom hobbed bolts (or equivalent)
  • Lighter than a stock single Accessible Extruder
  • Integrated hot end cooling
  • Mounting hardware for Prusa i3v printers

Printable Files

All of the files are included for the entire extruder system for 1.75mm and 3mm filament, Hexagon and E3Dv6 hot ends. To assemble the entire system you will need to print:

One extruder block
  • For 3mm hot ends: Double Flex Block-300Universal.STL
  • For 1.75mm hot ends without a liner: Double Flex Block-175Universal.STL
  • For 1.75mm E3D hot ends with a PTFE liner and fitting: Double Flex Block-175E3dLiner.STL
Hot end-specific parts
  • Hexagon hot ends: All of the parts with "hexagon" in the file name. An alternate fan shroud is provided for the Hexagon AO.
  • E3D hot ends: All of the parts with "e3dv6" in the file name.
Common parts

You will need two copies each of the idler blocks, idler pins, pulleys and round spacers and one copy of everything else.

Optional parts
  • I3VXCarriagePlate.STL - replacement for standard i3v X carriage plate
  • Adjustable I3VXCarriagePlate.STL - X carriage plate with a larger hole to use an extra V-slot eccentric in one of the upper holes for leveling

Print Settings


MakerFarm Prusa i3v










I recommend ABS. Some people have reported great success with PETG.


Required Hardware

In addition to the printed parts, you will need the following vitamins:

  • Hardware kit
    • Available here
    • GT2 20-tooth Pulleys with set screws (2)
    • GT2 200mm Belts (2)
    • 688ZZ 8x16x5mm Bearings (6)
    • Extension springs (2)
    • Fiberglass/Polyimide insulator
    • M2.5×10 socket head cap screws (2)
    • M4x.7 hex nuts (2)
    • M4x20 button head cap screws (2)
    • M3 flat washers (6)
    • M3x.5 hex nuts (11)
    • M3x25 socket head cap screws (3)
    • M3x16 button head socket cap screws (10)
    • M3x12 flat head socket cap screws (10)
    • M3x8 socket head cap screws (6)
    • M3x6 button head socket cap screws (2)
  • Light springs for flexible filament (optional)
  • Hobbed bolts with jam nuts (2)
  • Hot Ends (matched pair)
    • Hexagon
    • E3Dv6
  • NEMA 14 stepper motors (2)
  • HXT-900 Servo
  • Z probe switch
    • You can use virtually any snap switch, including the one that came with your MakerFarm printer.
  • 25x25x10mm fan (Hexagon hot ends only)
  • 40x40x10mm fan (for print cooling)
    • A 40mm fan is now included with most Hexagon hot ends

Assembly Instructions

Detailed assembly instructions can be found here:

Firmware setup:


Release Notes for Version 2.1

Version 2.1 includes the following changes:

  • Added longer versions of the Z probe arms for switches without levers
  • Fixed thickness of Hexagon double groove mount for a better fit

More from 3D Printer Extruders

view more

File Name



All Apps

3D Print your file with 3D Hubs, the world’s largest online marketplace for 3D printing services.

App Info Launch App

Auto-magically prepare your 3D models for 3D printing. A cloud based 3D models Preparing and Healing solution for 3D Printing, MakePrintable provides features for model repairing, wall thickness...

App Info Launch App

Kiri:Moto is an integrated cloud-based slicer and tool-path generator for 3D Printing, CAM / CNC and Laser cutting. *** 3D printing mode provides model slicing and GCode output using built-in...

App Info Launch App
KiriMoto Thing App

With 3D Slash, you can edit 3d models like a stonecutter. A unique interface: as fun as a building game! The perfect tool for non-designers and children to create in 3D.

App Info Launch App

Print through a distributed network of 3D printing enthusiasts from across the US, at a fraction of the cost of the competitors. We want to change the world for the better through technology, an...

App Info Launch App

Quickly Scale, Mirror or Cut your 3D Models

App Info Launch App

3D Print a wide range of designs with Treatstock. Easy to use tools to get the perfect result. The global 3D printing network that connects you with high-quality and fast working print services nea...

App Info Launch App

I'm working on putting together a parts list so I can build this and put it on my FT-5 and I was wondering if you think there would be any advantage to using .9deg steppers?

I don't think there's much point, and depending on the details it could cause problems. If you're using normal 1.8deg (200 steps) motors, with a 1/16 microstepping driver, the 4:1 belt drive and an 8mm bolt, you're already around 640 steps/mm. For 1.75mm filament, it doesn't seem like more resolution than this will be very helpful unless you're printing slowly with a very small nozzle. Switching to .9deg motors will double your volume resolution, but will also double the number of steps you have to make, and this will likely cause problems getting a fast retract. Ideally, you should be retracting at 30mm/s or more to get a crisp stop, and most stepper motors are limited to around this speed by their inductance when running on 12V. If you are running the steppers on 24V or have very low inductance motors (1.5uH or lower) then maybe you could make .9deg motors work and still maintain your retract speed.

Thanks for the sanity check. I figured the same with the 4:1 ratio. I'm getting ready to order the hardware and I'm trying to decide if I want to go with the AO or the regular hexagon. I've got the regular on my delta and I love it. Not sure what difference I would see between the two but I know the AO is used on the Taz so they must think there is a noticeable difference.

My understanding is that the AO has more mass in the heat block, so it's easier to maintain the temperature precisely, at the expense of having less cooling area on the heat sink.

Compliments splendid job. I have two questions:

1: what is the total width?

2: where did you get the belts?

I have a few in stock, if you're in the US: http://clough42.com/product/200mm-gt2-belt/

But it looks like you're in Italy? I would check out eBay or AliExpress. Another useful search term is "2GT-200"

Just measured it, at 148.5mm width.

I bought mine on Aliexpress, just search for GT2 200mm belt

I found it on Aliexpress, very kind, thank you!

Jesus, now that is a beast! 0_o


I've been having some trouble with the ao hexagon jamming when using pla during dual extrusion -- even if I set the hotend to drop to 170C or lower when idle, eventually the filament will jam. At first I thought it was just due to the (rather excellent!) hobbed bolt grinding the filament down, but it does not affect abs and I was able to feed 20mm, retract 15, and repeat for dozens of cycles when using just one. I also have the recommended sunon maglev fan and have yet to find a more powerful 25mm fan.

Has anyone else experienced the same problem or have any fixes? I think that the heatsink on the hexagon is simply too short to cool two of them with a single 25mm fan adequately enough to prevent pla from swelling. I was contemplating trying to design a shroud to fit onto the hexagons (pushing with 2x40mm fans and reversing the 25mm to blow upward), or removing the heatsink shroud and just using a pair of external shrouds, but was hoping someone else had already experienced/solved this problem.

May I make a suggestion: Add some kind of slot to the extruder block for holding the PTFE tubing. With long retracts on flexible filament, the filament sometimes tilts and prevents to be fed further into the nozzle....Just an idea

Are you using 1.75mm filament? If so, there's a version of the extruder block for the 1.75mm E3Dv6 with large bores to hold the PTFE liner. That's the version I use on my printers.

you happen to have this in a single flex extruder would you??? i have a wanhao i3 and it doesnt have the capabilities of dual extruders without having to swap the entire motherboard

You have a couple of options. You could use the double extruder, but only connect one motor, belt and hot end, or you could go with the Itty Bitty Belted Extruder (http://www.thingiverse.com/thing:389105) which is the single extruder I used as a test bed when designing the double extruder mechanics. I still use it every day on one of my printers, and I use it regularly with 3mm NinjaFlex.

Itty Bitty Belted Extruder

thank you for the quick reply but in your opinion which option would be best?

They both print well. If you already have an Accessible extruder, you can transfer your bearings and hardware over to the Itty Bitty Belted Extruder. If you go with the half-double, you'll have to get new bearings and hardware. It's up to you.

How do you make sure the heights of the extruder tips are aligned? Im thinking about printing this ;)

There are two ways I have done it. If you are using auto bed leveling, you can actually tilt the entire X axis to level the heads. The other way is to print out a new back plate for the X axis with a large hole for an extra eccentric cam on one of the top wheels. This allows you to adjust the level by turning the cam.

Thank you for that great design!
Sadly I'm not able to get that thing working. I made my own hobbed bolts, but all of them dont work. The filament just get's eaten by the bolt.
I've ordered now your bolts on ebay, I hope that will do the trick.

There are lots of factors that can affect bolt stripping. The geometry of the teeth on the bolt can make a big difference. It's also possible to run into trouble with spring tension. I've seen problems with too little tension (slipping and grinding) and with too much tension (deformation and jamming). You can also try changing speed and temperature. If nothing works, you might have some debris floating around in your melt chamber. This is especially an issue if you switch filaments a lot. Swapping hot ends or nozzles can help determine if this is what's happening.

Hello, I received your bolts. They are very nice, but I still had stripping filament. So the only thing which did the trick was lowering the extrusion feedrate from 22 to 2! I don't know if this is ok, but at least I can do some basic calibration.

Interesting. Is that in mm/sec or mm/min? 2mm/sec for the filament is a reasonable feed rate. 2mm/min is very slow.

It says mm/sec in marlin. I was just worried, because in your fw you have 22 which is way faster :-D.

Ahh...yes. That's the absolute maximum feedrate. You would only normally run that fast for retractions. Normal hot ends can't generally melt the filament that fast.

Ok I see, but how is it possible to just reduce the extrusion feedrate, without touching the retraction feedrate? I've now a lot of oozing problems(using 1mm retraction distance) and I think a quick retraction might help too. At the moment I'm limited to the same 2 mm/s which I've hard coded in marlin. I've did some research and found the command M203, but I'm not sure if that will only affect the extrusion speed and leaves the retraction speed alone(that would be perfect).

Usually, you have the feed rate in Marlin set to the maximum the motors will support, but you configure the actual feed rates in your slicer. Generally, the Slicer calculates the forward feed rate based on the printing speed, the diameter of the filament, the diameter of the nozzle and the layer height. The retraction feed rate is usually a configurable item (in the slicer).

i made a remix of this, so it fits two Nema 17 motors, and it fits on the original Prusa i3. i've also made a fanshroud for e3dv6 that fits two 30mm fan. And last but not least there is a inductive sensor mount. Clough42 feel free to add the files to the files section of yours. http://www.thingiverse.com/thing:1649430

Prusa i3, Nema 17, Itty Bitty Double Flex V2 Extruder

Thanks for sharing. I have had lots of requests for NEMA17 motors. What length/torque motors are you using and what's the total mass? Does the extra weight affect the print? I would expect to see more ringing on the left and right sides of printed parts if so.

I'm using NEMA 17 motors, with a length off 33mm and a rotor torque off 35g.cm^2. About the extra wheight, i don't know, because i only made three print so far with it, but i saw a little bit of ringing on one of the prints. i don't know the total mass of the whole extruder with the NEMA 17, but one of my NEMA 17 motors weigh about 220 grams

looks like a v8 engine

clough42, can I get a merged complete assembly to put into my solidworks to get be able to create a mount for my corexy.

Sure thing. I'll PM you the details. Please be sure to share whatever you create!

And now, I can print the engine block, err, uhh extruder block in PET-G with the letters 'C42' and 'IE' in black PLA...

http://www.thingiverse.com/thing:1575952 (imbed a monogram in the stl...)

Customizable Monogram Pendant with multiple loops_Dual
by gddeen

UPDATED: Version 2.1!

I just released version 2.1 of the Itty Bitty Double FLEX extruder. The update includes longer Z probe arms and a minor tweak to the thickness of the Hexagon double groove mount so it should fit better.

I had to modify the servo arm included with the e3d stuff (from your website) to be longer as it was too short compared to my e3d. I extended it 10mm.

Apr 2, 2016 - Modified Apr 2, 2016
clough42 - in reply to snowzach

Oh, that doesn't sound good. Which file did you print? What switch are you using? Are you using the E3Dv6, or the Volcano? Is it an official v6, or one of the Chinese clones?

It's an official E3Dv6 I bought from Makerfarm. I printed the arm that was in the e3dv6 directory although it's possible I screwed something up.

No, you didn't screw up. I just checked, and it was my bad. I have longer versions of the Z probe arms for both the Hexagon and E3Dv6 that are designed for use with switches that don't have levers. These are included in printed parts kits purchased through clough42.com, but I never got the updated files here on Thingiverse, or on the web site.

I just uploaded the extra long files here and updated the downloadable parts bundle on my web site. Sorry for the inconvenience.

Geeze... Now you tell me... I redesigned THAT one awhile back. My Zprobe 1573283 fits a E3DV5.

Also, there is no DUAL MINI FAN MOUNT part to mount the 2 25mm fans to fit E3Dv6 heatsinks. So...

I used 30 guage magnet wire and weaved the fans together and to the heatsinks. It is
much lighter than the fan mounts. It is also weaved to keep the nozzles the same dist apart.
But metal will stretch soon...

Hey, no problem at all.. Thanks for a great design. I actually decided to throw out the server and am expecting a Proximity sensor int the mail any day. Can't wait to get this new printer going.

Hi, your extruder rocks! I made it fit to my MendelMax V3. Although not yet tested, I think this will be the foundation for some speed improvement (coming from a Bowden extruder).

Since I am so happy with it, I want to share the following additions with you, feel free to add them to your Thingy Files:

By the way: I love your calibration object along with your simple but nonetheless very useful tool to calculate the right settings!!

There is room for (slight) improvement: since maintenance is part of the business, it would be nice to have a short section about how to quickly disassemble the Extruder in order to clean nozzles etc.

So, final word: two thumbs up for your product and services. I like the result and I truly loved your exceptional documentation. There is only one thing that was even better: reaction time (questions, shipping, etc). Less than 12 hours. Wow.

Thanks for sharing and wish you have lots of people buying your kit!

When we create models and tag them in Thingiverse, what is a good tag for dual extrusions? dual_extrusions 2_colors
anything else?

Thanks. Feel free to post your parts as derivatives, and they'll show up in my Thingiverse listing so others can find them.

Hi, do you think these would work for the light springs? I'm trying to source parts in my country but I can't seem to find the exact same spring as you have in your store.
Here's a picture: goo.gl/tHCg9h
Total Length: 36.5 mm, Spring portion Length: 25 mm, Ring diameter: 5 mm, Material: carbon steel

Jan 29, 2016 - Modified Jan 29, 2016
clough42 - in reply to juliafeec

Springs are very hard to specify, since the thickness and material of the wire varies so much. I actually cut and bend my springs to length from longer stock, but there must be something available near where you live that is similar.

You're looking for a spring that will provide between 0.5 and 1.0Kg force per spring when stretched to 50mm.

But that isn't a magic formula. The ones I have work well for the filaments I've tried, but you can likely use a lot of different materials. You could even try stacking up rubber bands across the screws. They won't last as long as springs, but they will work.

Ok, will keep that in mind. Thanks!

Could we get a side bracket to hold an inductive/capacitive sensor as an alternative to the servo/switch?

That should be straightforward. I don't actually have one to use for the model. Is there an existing model that works with the standard extruder you can point me to as a starting point?

did an 18mm inductive sensor bracket ever get made?

I haven't gotten back to it. I don't know if anyone else has.

Jan 18, 2016 - Modified Jan 18, 2016
AbuMaia - in reply to clough42


I forgot that I had modified it for the i3v. Sending you a link in a PM in the forum.

Makerfarm Non-Contact Z-Probe Bracket
Comments deleted.

The download does not have all the files in it.

These are what is there -

flex blocks
idler blocks
idler pin
servo shelf brackets
servo spacer

You're totally right. I'm not sure what's going on there. I don't provide that zip file. It's generated by Thingiverse. I'll try to contact them.

Is this a replacement for the itty bitty double, or just for those using flexible filament?

It's a replacement. If you already have one and are not having trouble, there is no particular need to upgrade.

where do i find the belt or do you have a file for printing it? i know of people printing them with lots of success.... kinda wanted to try....

I have never attempted to print the belt. I would think a printed belt would be very stretchy, but I've never tried.

200mm GT2 belts are available from lots of sources, including my web site: http://clough42.com/shop/

  • Could a printed clip be used to make a belt from a long piece of belt? I was thinking 1 side would have 3 teeth which runs smoothly over the small pulley. The other side clamps the ends. Then I could test before actually buying a fixed belt size.
  • I found http://www.thingiverse.com/thing:84339 for dummy stepper motors and bearings. (I added the missing 688zz)
  • I found http://www.thingiverse.com/thing:193647 for temp "hobbed" bolts.
  • I'm using all Metal J-H E3D 25mm center to center. (a previous Itty bitty didn't fit two extruders. Luckily I 3d printed and fit everything together to see it didn't work prior to printing everything and seeing it didn't work. Hmmm. Heh heh heh.)
  • I'm still going to go to the other 2 things (ver 0, 1, and this one) and read all the comments. I don't want to miss cool stuff.
  • I have a HICTOP i3dp08 and no clue at all what a makerfarm is. It probably just means that steel Angle bracket attached to X rods has to be replaced...
  • I'm concerned because my extruder has a 4.86mm female fitting at the top which connects to a male 4.86mm compression fitting with a long PTFE tube and another male fitting. That is what I started with, a tube to put the heavy motor parts elsewhere. (I only have extruder and host, no remote motor and filament push/pull traction gear. Sorry for making up all my terms. It's probably some jeff bowden richard wade whatachacallit.)
    I'm hoping the shelf bracket securely fastens the extruder somehow and I can eliminate the cable feed here.

Great work! Unbelievably awesome jpegs. Like something outta autocad fusion 360. (I need to ask the autocad people to give me a shiny, dimpled, z wobbled, extremely monochromatic filter so I can publish what MY parts look like with shading!)

OpenSCAD stepper and bearings script
NUT JOB | Nut, Bolt, Washer and Threaded Rod Factory