Rotating Skull Gear

by 3DCentralVA Jul 25, 2012
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Can you please put a step by step assembly up

I needed a nice large raft for first layer, and I used the "bones" from the other heart gear files I have. Otherwise, I'm extremely happy with this print!

What program was used to create this model?

Thanks for your note! "openscad" is the program used to create it. In fact it was quite easy to modify the original program used to make a heart gear into a skull gear -- I just needed to put the skull STL in the right orientation, and then re-calculate everything on that instead of the heart! If you are familiar with computer programming, you will feel right at home with OpenSCAD -- otherwise though it might be a little intimidating.

I must try this! Do you think you could make a Darth Vader or Yoda gear skull? That would be AWESOME!!!

Had to use hot glue to glue down the first few layers or else it lifts later.

Are there any instructions about how to assemble this puppy? I'm worried that once attach a piece I will not be able to detach it from the clips. Which sized clips go to which gear? and on which side of the center piece? Thanks!

We don't have any visual instructions made for this right now. But, the clips are definitely re-attachable, so as long as you avoid the superglue you shouldn't have any problems.

Have you ever assembled the rotating heart gear? It's very similar to this. Like the heart, it's kind of like a puzzle the first time you put it together. The small clips go into the small gears, and the big ones into the big gears. Similarly, the small gears go into the small faces of the center, and the big pieces into the big faces.

I would start with the large gears with cheek bones (gears 2 and 4), into two adjacent large faces. Then attach the two small gears that are NOT the rounded ones, but rather have parts of the eye socket and spinal attachment. From there it's harder to explain, but just think of it as a puzzle, and try orientations until it comes out smooth.

Hope this helps!

Very Helpful! thank you!

In the made section I added one yesterday with shots of every angle. This might help you see where all the gears go. It's the white one on the black board with a white grid.

Do you need support printing the large ocular gears?


While you can still print & clean it up by hand, the two cheekbone gears (gears 2 and 4) do print best with support. If you have an UP printer, I'd be happy to provide the UPP file that I use (with settings included).


I have a Printrbot Simple and use Repetier-host V0.95F with slic3r. I have already printed everything but 2,4, and 6. I am printing 6 right now.

Since your work is a remix of two others that both have ShareAlike in their license, doesn't your work need to be licensed ShareAlike as well?

Ah, you're totally right! Thanks for the heads up -- license has been updated.

Thanks! Yep, that's actually us printing and shipping them :). Amazon does not let us put external links anywhere, so for attribution we're including all the info & links in with the packing slip.

Hey I'm trying to print your skull out. First I'd like to say it's a ridiculously cool looking model, and I can't wait to be able to assemble it! Unfortunately, the pins that I've printed out are rather too large. Were they meant to be printed in PLA or ABS? The rest of the skull I've printed out in PLA, and I thought that using ABS would make the pins more flexible, and therefore easier to fit into the hole. Should I reduce the size of the pins? I know the setting of filament always causes a change in the size of things.

Thanks so much!

I want to print this as one piece to make a gear shift knob. I have the nylon. Does anyone know an easy way for a newbie to assemble this as a solid print and maybe add a base to drill and tap for the shifter? This would be the ultimate gift for a gear head!

Cool idea! Hm, so you would not need the gears to rotate then? What sort of printer do you have? I imagine you will have lots of difficulties with support if you try to print it out all as one piece.. why not print them separately and assemble, but add some super glue if you want it to stay solid & together?

As for the last piece, that shouldn't be too difficult. pick whichever orientation you want to be down toward the shifter, and subtract out a cylinder of the right dimensions.

is it possible to mod this code so it would be a tardis i tried but completely failed.

Yeah it should be possible! You just need to have a solid-body to intersect with. The tardis version probably failed because the popular tardis model is hollow in the center. If you close up the center, then it'll probably work. Though, it might work better if you shrink the tardis along the Z axis so it is closer to a square.. Let me know if you need help.

Printed at 50% reduced size.  See photo attached.  Pins tend to be a little loose, but still in all, it worked.  Pretty cool - thanks!!!

So, I'm curious, what was your process/workflow for generating this.  i.e., details beyond you mashed up the heart gear and the skull.  Any details would be appreciated.

 Hello, I'm sorry I missed this! I used the Emmett's openscad code for the screwless heart gear (this thing's derivative).  When you load the code into openscad, there are lots of the useful functions which perform this "mashing up". Effectively, you are intersecting this "rotating gear" mechanism with another shape. Try it first with a sphere or cube, and see how the rendering changes as you rotate and move the sphere or cube about (you can do this in another program; I used blender to export the STLs to be loaded into openscad).

Though it does not work with all shapes.. I've been trying to make a 'brain gear' for a while, but all the brains I find have too many holes and cavities.

I've printed out three of these, white/bone, black, and yellow.  It's a perfect design for Halloween.  Assembly was easy but took a little readjusting of position to get the fit just right, i.e., a "smooth" skull.

I think I will try to scale them and see how a larger and much smaller version work.

So the pins might need to be a little bigger for a multi-material print. But I like how it turned out! Thanks for creating it, and I uploaded a picture with the parts and pieces so you could see it.

Any assembly instructions? I printed the gears on a ZCorp 650, and the pins on a 3D Systems Projet 3000. The first pin file was corrupt, so I had to reload it. After I CA the gears I'm looking to snap it together with the Projet printed pins. Just wondering about how to snap it all together? Orientation on the center would be helpful!

Hey! Oh interesting, I wonder how it looks on the ZCorp compared to the commodity machines. Assembly is similar to the heart gear from which this was derived.

Start by inserting the pins to the center. The large pins are paired with the large faces, and small with small. It is easiest I have found to start with the forehead. It is the largest of the small gears, and you can see the brow ridge. Insert it into one of the small faces. Next insert the two l
arge gears with the cheekbones and eye sockets, so that the eye sockets line up with the brow ridge of the forehead piece. Next insert the spine piece, another small gear which will line up with the sides of the face.

From here, insert the back of the skull, which is a large gear piece with a smal
l point on one side; this point should face towards the bottom spine piece. Next, insert the top of the skull, the last large piece, such that the longer side is towards the from of the skull.

The last two small gear pieces look similar, but one is slightly longer. The longer one left hand side of
the skull, from the perspective of the skull; and the shorter in the right.

Let me know if this helps!

I love this thing! I'm having difficulty putting the three small gears in the proper orientation. When I look at the picture you have, the front small gear piece (with the nasal bone) is different than what prints out on the skull 1357 file. When I print out that file, none of the pieces has the distinctive nasal bone.

Hey -- thanks for the heads up! You are right, I had accidentally uploaded an early version with the skull at a different orientation, so the pieces look slightly different from the picture. Your print should still come together as it is, but a little different from the picture.

Sorry about that!

SWEEEET! printing this right now! NOW!