Filament Spindle MK1

A filament spindle is a critical upgrade for your MakerBot, especially if you do lots of printing. It keeps your filament dry, clean, and prevents tangles that are the nightmare of anyone who has ever printed without one.

The Filament Spindle MK1 may be a bit late to the game, but that has allowed us to design a spindle that is reliable and robust. We have tested this spindle for over a hundred print-hours and it has performed admirably. A few interesting features of this particular spindle design:

  • Horizontal orientation for smooth unspooling.
  • Enclosed box to keep filament dry and clean.
  • Stackable for multi-color or multi-material operators.
  • Acrylic front for easy filament viewing.
  • Ball bearing rotary table for smooth movement.
  • Quick connect guide tubing for a smooth, dust-free, jam-free filament path.
  • Rubber feet for grip and vibration noise dampening.

Spindle Design


After struggling with many vertical filament spindle designs, we went horizontal. Using a horizontal spindle makes a huge difference. Since the inner diameter of the filament spool will never be exactly the same diameter as the spindle hub, a vertical spindle has a lopsidedness that makes unspooling very difficult.

Since gravity will pull the filament down, the feed system on a vertical spindle needs to overcome the weight of the plastic in order to turn the spindle. This will typically end up with the filament cutting through the spool and getting jammed; eventually causing the extruder to strip.

With a horizontal spindle, the gravity induced lopsidedness is eliminated. In order to drive the plastic, the feel system only needs to overcome the friction of the rotary table and feed tube. Since the rotary table has a ball bearing race and the feed tube is made from low friction HDPE, it is a very smooth feed.

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 solenoid valves 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.


Assembly of the filament spindle is very straightforward. It is a mechanical only system with one moving part. The spindle kit consists of two main parts: the spindle and the box. The design uses the same t-slot setup as your MakerBot that you (hopefully) know and love. The kit itself goes together in under an hour.

Jump to the assembly page for full instructions.


The filament spindle has one use: to dispense filament without jamming. Therefore, the usage is very easy. Simply place your MakerBot on top of the filament box and feel the filament into the extruder. Don't worry about getting the plastic guide tube close to the entrance. As the filament feeds in and get extruded, the plastic will pull down to the entrance hole and stay there.

Accessing Filament

When the plastic is loaded into an extruder and you need to remove the filament, or get access to the filament to push on it, simply pull back the plastic tube. This will pull more filament through the tube and allow you access to the filament at the point where it enters the extruder.

Filament Safekeeping When Not in Use

One of the nice things about the stackable filament spindles is that you can have multiple plastics in use at any given time. When you remove one filament from your extruder, make sure you bend the end into an L shape so that it does not fall back inside the tube.

In Case of Spindle Jam

On very rare occasions (most often with new rolls of filament) the spindle will jam. The main causes are 1) the filament getting under the spindle and jamming and 2) the filament short-cutting through the other filament towards the center.

For problem #1, you should take the top off the filament box and get all the filament back above the bottom flange.

For problem #2, you can rotate the spindle a bit by sticking your finger into the filament guide cutout on the bottom and manually rotating the spindle.

Problem #1 can be completely eliminated by a quick and easy modification to the filament spindle box. Take either the top or bottom of the spindle and trace around it twice on some cardboard, the MakerBot packing is ideal for this. Cut out the two discs and then hollow out the middle to form two hoops, the hole should be big enough to fit over the turntable and allow it to spin fully. Next glue or tape the two hoops together to form one thicker hoop. Finally glue or tape this hoop to the bottom of your filament spindle box, place the spindle on top and check that is still spins freely. This should add some minor friction to the spindle which prevents it from gaining momentum when unspooling, especially after loading a new 5lb spool into it. This also prevents filament from getting underneath the spindle mechanism and jamming.


Preparing for Travel

If you are going to travel with your filament spindle box, it is recommended that you remove the filament spindle from the filament box and tape the filament to the top of the spool. If you keep the spindle inside the box, you run the risk of damaging the turntable.

Source Code

The design of this filament spindle 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.
* Google Code - download the release.
* Subversion - direct link to the release tag.

Unless otherwise stated, the content of this page is licensed under GNU Free Documentation License.