I designed this drain fitting for a coworker whose home was built in the 1970s with a plastic shower drain fitting that had become cracked.

Story and pictures on my blog at MySD300.blogspot.com

This two-piece template was supposed to guide you in cutting and folding a piece of cartstock to make a model with concentric rings that spin when you fold it, like the one shown in the video:
youtu.be/2QXgaSLgxq4

Alas!

The paper model didn't work very well when I tried it, but I decided to share it anyway. Maybe someone else can get it to work.

This is a living-hinge model with interlinked rings that dramatically spin around the center axis when the panel is folded.

youtu.be/2QXgaSLgxq4

The Snooze button on my Westclox 22651 stopped working because I broke a little pin on the back side of the button. This spacer restores normal function of the button.

Detailed repair pictures on my blog at
mysd300.blogspot.com/2012/04/same-day-repair.html

This is just a frivolous imitation of a 45-RPM phonograph record, which I built to take advantage of the way my Solido SD300 builds 3D parts out of shiny PVC. But it could also work in ABS if you dip it in acetone to make it shiny!

More pictures at mysd300.blogspot.com/2012/02/classic-45-vinyl.html

Try to assemble the 4 pieces into the shape of a latin letter T. Most people find it surprisingly challenging!

This is an adaptation of a traditional puzzle.

This is an implementation of Nikola Tesla's "Valvular Conduit" that acts as a one-way-valve without any moving parts.

blog.makezine.com/2012/01/05/the-tesla-valve-one-way-flow-with-no-moving-parts/

This implementation follows Tesla's patent diagrams, perhaps too closely. It works, but the cap is a bit leaky so I plan to re-design it in the future.

I made these files to verify my 3D printer built accurate part geometry regardless of part orientation.

There's a series of star-shaped shafts at various angles, and a series of disks with star-shaped openings that should fit over any of the shafts in all 8 rotations.

A recent comment by Tony Buser (http://www.thingiverse.com/derivative:21136) got me thinking that this might be an instructive test for hobby printers, too.

This is a slightly more challenging variant of Dovetail Triangle that only opens when held in a certain orientation.

Watch the video for a demonstration:

youtube.com/watch?v=JnMRREjfPyc

This hook holds onto the handles of shopping bags to keep them from sliding around on the floor of a MINI Cooper. It snaps onto the wire frame of the Cup Holder accessory that was commonly supplied on MINI Coopers from 2002 to 2007.

This is a simple stand-up support for the Antichron sculpture.

More pictures of how I built my sculpture (with some unusual difficulty) on my blog at mysd300.blogspot.com/2012/01/antichron.html

Slide an envelope or memo into the slot and the floating barrel will take hold of it by wedging action and simple gravity. Notes can be removed by sliding them sideways or by lifting the barrel with your finger.

I use it to accumulate outgoing mail near a door where I will see it when I leave home each morning.

There's a video showing how it works at mysd300.blogspot.com/2011/12/hands-free-memo-holder.html

This is a 'kit' for designing or building magic screw threads that will (hopefully) build on a Thing-o-Matic and similar hobby printers. This should enable you to build a bolt and nuts so that one nut tightens normally while the other seems to turn the wrong way as shown in this video (this is the new model data):

youtube.com/watch?v=gx_OKYA3_Iw

The ancestor model did not build accurately on hobby-type 3D printers because (I think) the geometry had atypical overhangs that could foreseeably flatten out during extrusion. Instead of fighting those overhangs, this Magic Screw version tries to exploit them by building overhangs in straight lines between supported walls. It's just a conjecture (I don't know if I'm right) but it's illustrated in my blog at mysd300.blogspot.com/2011/12/magic-screw-for-makerbots.html

This is a square solid inside a triangular hole within a triangular solid inside a square hole.

The predecessor to this design featured a triangle inside a square hole within another triangle inside a square hole. It sounded nice but the square hole broke up the symmetry of the triangle, plus it didn't exploit the reciprocal capability of a reuleaux triangle to contain a square inside a triangular hole.

In the animated series Moral Orel there's a DO NOT DISTURB sign posted near Clay Puppington's den with a pictogram of a drinking man.

Now you can build it as a plastic card you can hang on any convenient doorknob. It instantly communicates why the occupant should not be disturbed.

As a prank, hang it on a friend or relative's door!

Two nuts travel opposite directions on the same thread! As seen on YouTube! youtube.com/watch?v=o-fPsvqjqZI

Update 27 Oct 2011: I've uploaded a new trick nut triplescrew_backward_floor.stl which eliminates superfluous slack and reduces the overhangs to where they might be buildable on a Makerbot.

The YouTube video inspired Thingiverse user msruggles to design his own "Screwy Screw" thing. The STL files below are the originals, which were used to make the video, which inspired msruggles to make Screwy Screw, which inspired me to upload the STL files below...oh gosh, I'm completely lost!

Don't know how it works? Obviously there's a trick to it, but I encourage you to try to figure it out before you "spoil" the fun by downloading the files. Try designing your own!

More discussion on my blog at mysd300.blogspot.com/search/label/screw

I designed these parts to help adapt Gear O'Clock to use a craft-store clock movement, add decorations, and cusomize it for the ArtMinds Clock Movement kits sold at Michaels.

Here's a whole web store devoted to clock kits, including high-torque movements: klockit.com/

Review these files and compare the ones in the original Gear O'Clock to select which parts are most appropriate for your 3D printer and your choice of clock movement. (In any case, you will need the numbered tabs from the original Gear O'Clock Thing.)

My blog has a detailed, fully-illustrated explanation of the parts at mysd300.blogspot.com/2011/10/gear-oclock.html

And here's a YouTube Video showing the two new animated versions of Gear O'Clock youtube.com/watch?v=nzn_2I1OYYw

To the best of my knowledge all parts can be built on FDM without support. For consistency all units are inches.

This is the shape of a rhombic dodecahedron divided into four identical pieces in an unintuitive way. Luckily you don't need to be familiar with the final shape: when you discover how to fit the pieces together they will converge into a rhombic dodecahedron.

Here's a YouTube video showing how the puzzle fits together: youtube.com/watch?v=MpmkWj1LPwE

It's also described in my blog at mysd300.blogspot.com/2011/10/rhombic-dodecahedron-puzzle.html

This is a trick dovetail joint. When assembled it looks impossible, but it's trivially simple to open.

I've searched online and found lots of other people have independently invented this mechanism, probably going back over a century. Some designs have added latches and machinery, but some details are universal!

nrp wrote a script to generate keys compatible with Kwikset KW1.

But the obsolescent KW1 has been falling out of use in new locks for almost two decades so I adapted the script for the newer 6-pin KW10 locks. (The KW10 doesn't add any other sophistication--just one extra pin.)

I built this stand to house five LEDs for illuminating the Geek Campfire thing. It has sufficient internal space to house the battery module, switch, and wiring from five electronic-candles I bought at a local Target store.

Here's a video of the animated fire at youtube.com/watch?v=o26lrV07X54

More pictures and explanation on my blog at mysd300.blogspot.com/2011/05/animated-geek-campfire.html

This is another maze-box with a lid that must navigate through a maze to take it off (or put it on).

It's been reconfigured to use a little more maze-solving psychology so the user tends to make wrong turns while trying to open the box. Most of my testers made wrong turns at every intersection except one. (Closing isn't as difficult as opening, but it a bit more complex than the original model.)

This was an attempt to adapt Chris K. Palmer's SlideTab objects to 3D printing while retaining the same joint structure as the Robo-cut version.

It does work, as demonstrated in the pictures, but the parts had to be so thin and so flexible that it's not practical to build on anything other than a Solido SD300, Invision LD, or MCor Matrix.

So I'm sharing the files mainly for their academic value. The geometric shape models have wall thicknesses from 0.2mm to 0.6mm, and the hats vary from 0.2mm to 0.4mm.

This is a gift box of sorts, made of six identical parts that go together in a somewhat puzzling manner. There are three styles, each held together by a combination of tabs and/or slots.

Boxy #1 - Each part has two projecting tabs and two slots; the box is held together by arranging the parts so two tabs on each side lock into the slots of two adjacent sides while two other slides lock into this side's slots. This version works requires material with a balance of flexibility and rigidity.

Boxy #2 - Each part has to projecting tabs like #1 plus tabs that lock together in groups of three at the corners. This version works best with fairly flexible material. It's the most secure version, but also the most complicated.

Boxy #3 - Each part has tabs that can lock pieces together at the corners. This version works best with fairly rigid material, but needs sufficient flex to get the corners into place without breaking. This is probably the simplest box to assemble.

(Undoubtedly it could be adapted to laser cutting, but I haven't translated them.)

More pictures and description in my blog at mysd300.blogspot.com/2010/12/puzzle-box-gift-cube.html

This is a pair of mirror-image rattleback models derived from jasay's original thing.

When the "cw" model is spun clockwise it will reverse direction to spin counterclockwise.

When the "ccw" model is spun counterclockwise it will reverse direction to spin clockwise.

Demo video at mysd300.blogspot.com/2010/12/rattleback-twins.html

This is designed for PVC laminated-object-modeling 3D printers, but it may work in flexible materials on other machines (possibly nylon).

The SD300, SD300 Pro, and Invision LD printers build a "test part" that folds up and snaps together into a nice little pyramid. I designed foldable_oct.stl to enable five standard test parts to be stacked to build a larger pyramid. The puzzle is to figure out how to utilize the new piece to make it possible.

NOTE: foldable_tetra.stl is equivalent to the SD300's standard test part, but it has a round hole that makes it easier to assemble and disassemble the parts. You don't need it if you've got enough test parts lying around, but it's nice to have if you want to un-snap the pieces.

This is a 2x2x1 puzzle using just four pieces. Many designers use this puzzle as a starter project, but this one is unique in requiring only four pieces. No additional screws, pins, or other parts.

Several designers have inquired about this model since I uploaded it to Shapeways, so I'm posting the files here for the benefit of anyone who wants to learn from the source files.

If you can't build it yourself, you can buy it from Shapeways at shapeways.com/model/112492/minimis_2x2x1__hollow_.html

This is dissection of a sphere into two identical pieces, which includes a hollow cavity when assembled. This is derived from the same basic OpenSCAD script as my previous Hemi-demi-sphere submission.

A quadrisection of a sphere into four identical parts with some novel attributes:

1. The parts have no overhangs.
2. The flat 'bottom' is completely concealed after assembly; there are no flat spots on the exterior of the sphere.
3. Exterior is made entirely of 'sidewalls' where the resolution of FDM really shines.

My test samples were built in transparent PVC on a Solido SD300 Pro, but my goal was to design a Makerbot-friendly shape. Based on feedback from friends, I've adjusted the contours so the pieces 'grab' onto each other after assembly.

More pictures and discussion at my SD300 blog entry at mysd300.blogspot.com/2010/05/novel-decompositions-of-sphere.html