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Filament Nudger for 3Doodler

For various reasons, the 3Doodler sometimes stops extruding. This can happen with any 3D Printer. However, the 3Doodler is exceptionally easy to get going again by giving the filament a gentle nudge. The Filament Nudger is a hack to reduce the number of times the 3Doodler stalls or jams by providing a continuously nudging force on the filament.

Nudger without handle

3Doodler with Filament Nudger

The Nudger works with or without the Phaser Handle described in a previous blog : How to 3D-print a Handle and Trigger for the 3Doodler (and to make it look like a Phaser)    If you have access to a 3D printer, you can build a Nudger yourself by downloading these files on Thingiverse.

With handle

3Doodler with Phaser Handle and Filament Nudger

The automatic Filament Nudger was designed to be powered by a pair of rubber bands,  and it is cocked by pulling back on the Filament Grabber mechanism.

Cocking the Nudger

Cocking the Filament Nudger

The Grabber works like a 1-way clutch, pulling the filament toward the 3Doodler but releasing the filament when pulled in the other direction or when the Grabber bumps the back of the 3Doodler. The force applied by the rubber bands is effective in keeping the extruder going, but is not strong enough to prevent the filament retraction which conveniently keeps the 3Doodler from oozing between extrusions like a glue gun does.

Filament Nudger works with filament provided by 3Doodler

Filament Nudger works with filament provided by 3Doodler

When used with the filament sticks provided by 3Doodler, the Filament Nudger has the benefits of (1) reducing extruder stalls and also (2) it lets you install a new stick any time after the trailing end of a stick disappears into the 3Doodler. Without the Nudger, a new stick may fall out when the 3Doodler is tipped upward before the new stick is engaged, and this can be annoying.

Filament Nudger also works with longer 3mm filament

Filament Nudger also works with longer 3mm filament

With the Filament Nudger as a pre-feeder, Skip has been successfully using the same coiled filament that is used by MacGyvrBot (and other 3D printers). Warning: the use of such materials is not recommended by 3Doodler, and using any unauthorized materials will void the 3Doodler warranty!


Hinge pin



Create a hinge pin for the Grabber with small piece of filament, and put button heads on the pin with the 3Doodler.




2 Zip-tie Frame



Attach the Frame to the 3Doodler with a zip-tie.





3 Insert Skewers




Cut (2) 1/8 inch bamboo skewers to 7 inch lengths and insert them into the Frame (drilling out the holes if they are too tight, locking them in with small nails if they are too loose).




4 Insert Grabber



Insert the Grabber onto the filament and skewers as shown.






5 Insert Filament Guide




Insert Filament Guide over skewers and filament as shown (drilling out the holes if they are too tight, locking them in with small nails if they are too loose).




6 Hook rubber bands




Hook rubber bands over Grabber and attach them to Frame as shown.




 In our next post we will show how to use the 3Doodler to hack up accessories for itself!

Stay tuned!


from on May 9th, 2014Comments0 Comments

How to 3D-print a Handle and Trigger for the 3Doodler (and to make it look like a Phaser).

The 3Doodler  is a hand-held 3D printer!  The company is now taking orders.  Last summer it was a “crowd-funded” Kickstarter project, and we invested in it.  Our reward for sponsoring this clever invention was to receive our very own pre-production device in January. It is kind of a cross between a hot-glue gun and a 3D printer.

Doodler 1

Unlike a glue-gun that melts a stick of rubbery plastic to glue things together, the 3Doodler can melt a 3mm filament of ABS (a kind of plastic that many things are made of) and extrudes it into a softened web-like thread that can draw up off of the paper in the open air and into almost any shape you can imagine.  While it is intended to be used for making plastic objects by drawing 3-dimensional doodles, we use it primarily to fix plastic objects that have broken or to hack plastic things by adding features to them.  But more about that in a later blog post.

Now we would like to tell you how the team of MacGyvrBot and Skip have found a way to make this great product even better!

Doodler 2

We used Tinkercad to hack-up a model for a Handle and Trigger mechanism, and then we published the design on Thingiverse so that anyone with access to a 3D printer can download the .stl files and make a Phaser Handle for 3Doodler of their own.

or you can just click these links to download the 3 files




This kind of sharing is called open-source hardware design and the practice allows people to build on each other’s ideas.  You can also use Tinkercad to copy this design and modify it with your own ideas.  Progress is faster this way, so open-source design is the best way to get the most out of 3D printing.

Doodler 3

This Phaser Handle makes the 3Doodler look cool (like the Star Trek weapon), but it also makes doodling more comfortable (especially for people with small hands).  The makers of the 3Doodler obviously have plans for making a handle, because they provided a handy mounting bracket with threaded holes for M3 screws.  But we couldn’t wait!

The handle alone is beneficial, but using the trigger with the handle keeps the hand more relaxed during extended doodling.

Doodler 4

The Phaser Handle is attached to the 3Doodler with a pair of M3 x 10mm screws (any head design).  The trigger attaches to the handle with a pair of small flat head screws (such as 6-32 x 3/8 inch or M3 x 6mm) serving as hinge pins.  The screws are available at Lowes and Home Depot.

Doodler 5

The handle is hollow to allow access to a mounting screw (rather than having an infill of plastic in a sparse honeycomb pattern).  If your printer drops a few threads while bridging across the top of the handle, just let it finish the job.  Chances are it will recover before the top layer is reached.  If it fails, you may have to adjust your slicer settings (such as slowing the speed for bridges) and try again.

In our next blog post, we will show you how to use the 3Doodler itself to update the Phaser Handle.   The exercise will be a good demonstration of using the 3Doodler to hack an existing product.

Stay tuned!

from on March 10th, 2014Comments0 Comments

Can 3D-Printing and Computer Aided Design be of value in the Contemporary Urban Elementary School Curriculum?

The answer is a definitive YES!

During the past 4 weeks we tested this hypothesis as follows:

MacGyvrBot, a Personal Manufacturing Robot (also known as a table-top 3D-Printer) and Skip Meetze (both affiliated with INTERLOCK) volunteered to be part of the team teaching 4th, 5th and 6th Graders at School No. 52 in the Rochester City School District.  The 4 weeks of Tech Camp ran 3 mornings per week.  Michael Slade (another volunteer) and Susan Reuter (the teacher) rounded out the instructional team, and 20 students developed their skills at rapid prototyping while having fun learning some principles of physics.

America's Cup Toy Boat

The students each constructed an America’s Cup Toy Boat Kit (an STL file for the design can be downloaded at America’s Cup Toy Boat Kit by MacGyvrBot – Thingiverse) with soda straws and parts made on a Printrbot LC (Printrbot LC (v2) | printrbot).  Then they conducted a “shoebox regatta” where the sailboats were each sailed in a plastic shoebox half full of water.  The boats successfully (1) sailed on a reach (with wind from the side) (2) from one end of the box to the other, (3) without touching the side of the box, and (4) under the power of a student gently blowing through a straw from the side of the box.     This activity taught the students the basic principles of sailing while they developed confidence in their new skills of measuring materials (the straws) and assembling rapid prototypes (the boats) as MacGyvrBot chugged out the plastic parts right before their eyes.

Subsequently the students learned some basic skills in CAD using Tinkercad (Tinkercad – Mind to design in minutes) and Sketchup (SketchUp | 3D for Everyone).

At the end of the camp, students evaluated their experience by (anonymously) rating some of the lessons presented.

Student ratings

The Students’ ratings clearly show that using the 3D Printer and CAD are at the top of the list of things they would like to do again.

MacGyverBot in the classroom

A warning about Tinkercad:

There were special work-around requirements that we encountered for safely using the current version of Tinkercad with young students, and they will be further discussed in a later posting.  Tinkercad is resident on the internet cloud and not on the local computer, so continuous adult supervision is required (with an adult logged into the website) for Tinkercad to be safely used by kids (else the child’s access to sharing on the internet will be unsupervised).  Autodesk, the new owner of Tinkercad, is working on eliminating this requirement.

Parents and teachers, stay tuned… 

More about what we learned from participating in the Tech Camp will be discussed in later postings.  One of the neat things about rapid-prototyping in the classroom is the ease with which teachers, parents and designers can share their designs and ideas with each other.

from on August 2nd, 2013Comments0 Comments