I've been working with Greg Frost's gear generator. Getting the gears to mesh requires some math, or trial and error. As a programmer, I don't like doing either one more than once. :-)

This script lets you specify the axle spacing and gear ratio and get the circular_pitch parameter. It simplifies fitting gears together.

This is a very simple derivative of thingiverse.com/thing:6827 -- I've simply redesigned the rod-riders, based on some bushing code I wrote.

I am still testing this. No promises. :-)

This is an alternate part for thingiverse.com/thing:5586, TheRuttmeister's z-rider design.

The original design calls for ten small bearings to ride the burnished guide rods. Based on Prusa's work with PLA bushings, I got to wondering if the bearings were truly necessary. After messing with several sizes of bushing on my Cupcake's M8 rods, I'm pretty confident that this can be made to work without the bearings.

I didn't include the M3 bolt hole from the original. Cleaning the strings out of those tiny holes was enough trouble the first time I did it -- this time I'll just drill the durn hole.

I've printed some rough prototypes and it looks like it may work. I've included two versions: raw-bushing is designed to slide on the rod directly, and should be printed using PLA. sleeve-bushing is customized for a bronze sleeve bearing I found. You may have to adjust the SCAD file for what you can find.

I'm still not certain that this will take the torque load from the extruder. Might be an excuse to convert my MK5 to a Bowden extruder.

This OpenSCAD script can generate variations on Oscar Reutersvärd's 1934 optical illusion. My approach was inspired by a picture of Artur Tchoukanov's model that I saw in the news (which in turn was inspired by Ulrich Schwanitz). Unfortunately, the news article didn't include the math behind the illusion's construction (they so rarely do!), so I had to rederive everything from scratch.

Fortunately it took only a few minutes of basic geometry. This program demonstrates the math behind the illusion; it can generate triangles of arbitrary size and complexity.

After some research, it seems that all these figures are in fact inspired by the work of Marcel Duchamp, who was producing impossible-figure photographs by playing with concavity/convexity as early as 1950. Duchamp's techniques are presented alongside the Reutersvärd illusion in this 2004 article: toutfait.com/online_journal_details.php?postid=1375

I learn something new every day!

Upon purchasing the Plastruder MK5, I was bewildered to discover that there's nowhere to mount the actual control electronics. (I still have no idea what MakerBot Industries was thinking with this one.)

I rewired and hung the EC off the side of the bot, which is a reasonable configuration with the new relay board. This is the mount I used. I didn't post it initially because it's ridiculously simple..but it's so much simpler than the other EC mounts on here that I thought it might be useful to someone!

This is a replacement case and faceplate for the NuForce Icon µDAC-2. It's designed with thin walls for PLA, so it shows off the circuitry.

A friend commissioned this work. He purchased a NuForce Icon µDAC-2 USB audio device without a case -- it's 50% cheaper without the case, apparently: estore.nuforce.com/products/Icon-uDAC-to-uDac2-Upgrade.html

Your 3D printer just saved you 60 bucks.

Update: you will also need a backplate to make it all pretty and sealed. I hope to post a backplate shortly.

Use your 3D printer to create stamps, without wasting time and plastic printing excess handles. This reusable handle mounts to your stamp designs using a single M3 socket-cap bolt (8mm-16mm).

One example stamp included. Apply directly to forehead for best results. For external use only.

(Triangle design shown in the example photo is not included, but could be easily recreated by combining other designs I've posted...)

This was a bespoke design, but the client (my wife) graciously agreed to share it for non-commercial use. I'm told it resembles a video game icon from her childhood.

I made a few changes to the original that make it easier to print on a MakerBot Cupcake. I printed it raftless for smoother, flatter surfaces.

Changes: (1) slightly shrunk the gear teeth, so they mesh well without sanding; (2) adjusted the dimensions of tabs and holes for better assembly fit; (3) removed some non-manifold geometry from the inside.

I find that the MakerBot does poorly when printing small circles with lots of vertices. It tends to slow down unnecessarily, which makes things too thick.

I imported Will's z-stage guide into Blender and manually refined the mesh. Now the M3 bolt holes have 8 vertices, instead of 32. With careful use of the Stretch module in Skeinforge, the holes come out perfect.

When I switched to using an acrylic build platform, my retainer clips (designed for foamcore) stopped working. I worked with paperclips for a while, and then discovered OpenSCAD.

This is a very simple clip model that can be parameterized with your required dimensions (see the first few lines in the scad file).

In the pictures, you can see two different variations. Both have the same internal dimensions (the Gap parameter), but I varied the Reach and Thickness parameters. They both fit perfectly, but the smaller one prints faster and has less risk of hitting the z-stage. It's what the SCAD file defaults to.

Been moving into a new place, and I keep finding things that don't quite fit. These can all be fixed by fabbing small parts! ABS fabbed pieces have tremendous compressive strength -- with 0.3 infill grids I've tested mine past 180kg with no permanent deformation.

- The 26x19mm spacer holds my closet shelving rails away from the wall, since the tops are screwed into a 3/4" board the previous owner mounted. The centers are sized for a #12 screw, which in my case is a #12x2 driven into the studs.
- The 28x12mm spacer mounts my TV to my entertainment center, fitting around four bolts driven into the VESA mount on the back. It spaces it just enough to run cables (and use up the full length of the spare bolts I had).

More to come as I finish the house.

This is an omnidirectional wheel. If you know what this is, you know that they're a real pain to find, and expensive when found. They're expensive because it's a niche item, not because it's terribly complicated or hard to produce -- an excellent candidate for home replication.

Unlike commercial omniwheels, this comes with a Futaba-style servo mount already in place -- it's designed to be screwed directly to the servo. If this isn't your style, replace the object named "Servo Collar" in the Blender file with the mount of your choice.

v1.1 Update: Based on input from Simon Kirkby, I've enlarged the centers of the roller wheels and changed the axle mounts, which no longer need drilling.

Traditional (Staunton-style) chess set. The knight is a draft piece that I hope to revisit -- getting a recognizable horse-bust without exceeding the maximum overhang angles is hard.

Please note: my printer isn't here yet, so while I have sliced these models and inspected the tool paths that result, I haven't verified that they print properly on actual hardware. I would love feedback from any chess fans with printers! :-)