Itty Bitty Double ExtruderThe Itty Bitty Double Extruder is a compact, belt-driven double extruder for MakerFarm and other RepRap 3D printers.

Key Features:

  • Designed for Hexagon hot ends on 20mm centers (NOTENOT Hexagon AO)
  • 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)
  • 2mm narrower and 2g lighter than a stock Accessible Extruder
  • Integrated hot end cooling
  • Mounting hardware for Prusa i3v printers


Which Extruder Do I Need?

The Itty Bitty Double Extruder is a our original double extruder.  We also have a newer design called the Itty Bitty Double FLEX extruder.  Both extruders use the same hardware and both offer dual extrusion support on MakerFarm printers.  Here are the differences:

Itty Bitty Double FLEX Extruder (new):

  • Short, straight filament path for easier printing of flexible filament
  • Support for both Hexagon and E3Dv6 hot ends (NOTENOT Hexagon AO)
  • Wider (27mm) nozzle spacing reduces usable bed area slightly
  • Greater overall width (fits fine on i3v)

Itty Bitty Double Extruder (original):

  • Long, curved filament path works best with rigid filaments
  • Designed for Hexagon hot ends (NOTENOT Hexagon AO)
  • Narrow (20mm) nozzle spacing for maximum usable bed area
  • Narrower overall width may fit more printers

If you need more usable bed area or have a printer with limited space (like the original rod-style i3) you want the extruder on this page.  If you need to print flexible filaments or use E3Dv6 hot ends, you want the Itty Bitty Double FLEX Extruder.

Printable Files

Download the printable files here:

Itty Bitty Double Extruder Printable Parts

All of the files are included for the entire extruder system for 1.75 and 3mm filament.  You can print all of the parts separately, or you can print the provided plate files, which contain multiple parts to be run as a single print job.  You will need to print:

  • IttyBittyDoublePlate1.STL
  • IttyBittyDoublePlate2-1.75mm.STL or IttyBittyDoublePlate2-3mm.STL
  • Two copies of Parametric-Pulley-80-8-hex.STL (these will fit with Plate 1 if your printer can print a whole bed of parts cleanly without oozing or warping)

Required Hardware

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

  • Hardware kit
    • Available in our store:   Itty Bitty Double Extruder Hardware Kit
    • 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)
  • Hobbed bolts with jam nuts (2)
  • Hexagon hot ends (2) (NOTENOT Hexagon AO)
  • NEMA 14 stepper motors (2)
  • HXT-900 Servo
  • Z probe switch
  • 25x25x10mm fan
  • 40x40x10mm fan
    • A 40mm fan is now included with Hexagon hot ends

Assembly and Calibration

Assembly and calibration instructions are available here:

 Assembly Instructions

 Double Extruder Calibration

Additional Resources

Discussion thread on 3DPrintBoard

Itty Bitty Double Extruder on Thingiverse

 Marlin firmware fork on GitHub