The "Unicorn" is a toolhead for your MakerBot. Simply remove your plastruder and stick the Unicorn on to turn your bot into the ultimate drawing machine. The Unicorn employs a "floating head" system and allows the pen to move up and down relatively freely to accommodate for uneven drawing surfaces. Gravity provides a consistent contact force. An up/down mechanism is actuated by a servo to allow for super quick pen lifts.


  • Accepts pens (or other implements) from 5mm to 18mm diameter
  • Typical pen travel (in Z) = 5mm

Usable Drawing Implements

  • Pens. Fine-tipped felt ones are my favorite.
  • Markers.
  • Pencils.
  • Etching scribes.
  • Vinyl cutter heads.

Get one!

Gathering all the parts for building one of these can be pretty time-consuming. Some of the parts like the lasercut parts and the linear slide are difficult to source. Not only that, but buying a kit from the creators supports us so we can make it better. That's why we offer a kit that contains everything you need to build one yourself.
You may buy a Unicorn MK1 kit from the MakerBot Store.



Building the unicorn takes only about half an hour. It's a very straight-forward process where all you need to do is bolt together parts. We've simplified the design so that it only requires simple, common tools to assemble.

View the assembly instructions here.


Your finished plotter toolhead is ready to get drawing with. Before you dive right in you should check out instructions and tutorials for how to best use your Unicorn.

View the usage instructions here.

Source Code

The design of this toolhead is 100% open source. What this means is that we've released all the CAD files used for parts and the documentation under free licenses. The majority of the files are DXF files created by QCad. There are a few different ways you can access the files:

  • Thingiverse - download the source, talk about it, etc.
  • Github - download all of the scripts and example files.
Unless otherwise stated, the content of this page is licensed under GNU Free Documentation License.