Machining An Orrery

September 6, 2013 by Mike Szczys 26 Comments

What in the heck is an Orrery? If you’re looking at the image above we’re sure you’ve already figured it out (kudos to the big brains that knew the word). For those that don’t get it, an Orrery is a mechanical device that represents the movements of planets and moons. We never thought of building one ourselves. After seeing the machining process for what’s shown above we’re not sure if we’re excited, or scared off by all the work that went into it.

You might want to bust out the Chromecast and hit the sofa for this one. There are dozens of YouTube videos showing the build. From cutting sheet stock into round slugs, to making teeth, teeth, teeth, and more teeth it’s not just the gears that go into this one. You’re also going to needs the orbs themselves.

We have fond (perhaps scary) memories of the first time we saw an Orrery as a part of the set in The Dark Crystal.

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Git With Eagle: Add Meaning to Diff

September 4, 2013 by Mike Szczys 11 Comments

a-glimpse-of-git-with-eagle We love Git. We know everyone has their favorite version tracking tools. But even those that don’t care for Git should see the value of getting meaningful Diff data from tracking Eagle layout files.

Was that last sentence just gibberish to you? Let’s take a step back. A few years ago it was impossible to use version control with Eagle at all because the schematic and PCB layout software used to save its files as binaries. But then Cadsoft transitioned to saving Eagle files as XML. This opened the door for things like scripting to rename parts en masse and to track the files under version control. One problem with the latter has been that performing a Diff on two different versions of a file results in XML changes that are probably not human readable. [Patrick Franken] wrote this script to add at least a glimmer of meaning.

We’d love to see some kind of side-by-side highlighting on the schematic or board renderings themselves. But that’s quite a ways off if we ever actually see it. For now his script will take the Diff and print out the tables seen above denoting which types of changes were made from one version to the next. It’s a start, and we hope it inspires even more work in this area.

Scratch-built Gigapixel Scanner

September 1, 2013 by Mike Szczys 26 Comments

scratch-built-gigapixel-scanner

The presence of a camera in this image may be a bit confusing since we’re calling it a scanner. What’s actually going on is that macro-images this piece of art are being captured automatically. The multiple shots will later be assembled into one fascinatingly high-resolution image. The CNC scanner rig is [Charlie Romer’s] summer project.

Unfortunately [Charlie] hasn’t yet collected all the information on the project into one place. After the break you’ll find more images, as well as a few demo videos. The best place to start is probably his proof-of-concept from this Spring. He shows a single-axis CNC mount for the camera. It takes an entire row of images. The assembled photo from that test is shown below. We believe the faint yellow dots in the macro part of the example are fingerprints purposefully left by the printer called printer stenography to help prevent forgery.

The larger rig uses movement on two axes. The idea is that the artwork will be perfectly positioned so that manual focus set at one point will work along all points in the capture routine. He’s using a lamp for a light source but we’re sure he will upgrade so something like a ring light as the project continues.

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Many Iterations Of A Plywood Stool That Requires No Glue

August 29, 2013 by Mike Szczys 36 Comments

cnc-router-stool-design

At his local hackerspace [Vincent Sanders] noticed an interesting problem. The stools that they had were great in most cases, but there was one workbench which was very much the wrong height for them. So began his quest to design and fabricate plywood stools which use no glue for their joints.

The Cambridge Makespace (in the UK) turns out to be a perfect environment for this type of project. They already had a CNC router which can cut the plywood pieces, and there are other members who were willing to help train [Vincent] on the equipment. He found a design on Thingiverse which fit the bill, except for the actual measurements. He needed metric units to match the sheet stock available to him. Once converted he put together a stool that didn’t work at all. The thickness of the plywood just didn’t mesh with the tolerances of the joints. After wandering around to different suppliers in town, digital calipers in hand, he came up with a range of actual thicknesses and adjusted his joint design accordingly.

Of course this wasn’t the last revision. Even with the joints working the seat was still a little rickety. He moved to the next plywood thickness offered, redesigning the files to match. His final stool works like a charm, with five or six of them fitting on one standard sheet of plywood.

Rock Solid PCB Mill Built At Home

August 16, 2013 by Mike Szczys 41 Comments

Let’s all slow clap for [Daniel Taylor] who, after a long journey, got his home built PCB mill up and running with remarkable precision. That’s 10 mil traces with 0.5mm pitch pads. We’re impressed! The board will be used for breaking out the connections of an LCD screen he has on hand.

After seeing a CNC project as yesterday’s Fail of the Week it’s nice to look in on one like this that does some amazing stuff. In fact, [Daniel’s] creation has been working for months already. The link above is the project log he kept while hacking, tweaking, and retrofitting his rig to get the level of precision he was after.

Improvements include swapping out drawer slides for proper linear bearings and completely reworking the Z-axis along with a motor upgrade. For those that aren’t fans of the reading (how did you make it this far into this feature?) you can take a quick look at his image gallery which includes captions.

Fail Of The Week: The Follies Of A Bootstrapped CNC Mill

August 15, 2013 by Mike Szczys 34 Comments

fotw-bootstrap-cnc-mill

Anyone who’s built their own CNC machine from scratch will tell you that it’s no walk in the park. Heck, even commercially available (but hobby priced) 3D printers are no picnic to get running reliably. This offering is the tale of how [Brian Amos] failed at building a CNC mill over and over again. But hey, that ‘over and over again’ part is what makes great hackers. He not only documented what didn’t work, but shows the hacks that he tried using to work through each scrape.

We think the most interesting bits are in his second post, but start with the first one (it’s a quick read) to get the background on the project. The real issues start with a common one: a bed that is severely unlevel compared to the cutting head’s axes. The solution is to use a sacrificial bed, milling it out to match the surface to the tool. This exposed the next issue which is a misaligned Z axis. Some give in the entire support structure means problems with slop and backlash. And there’s even a very creative spiral-cut coupler to help account for alignment issues between the lead screws and motors.

The nice thing about building a mill is that you can turn around a use it to mill more accurate replacement parts. Just keep telling yourself that as you toil away at a project that just won’t seem to work!

We’re already looking for next week’s fail post topic. Help keep the fun rolling by writing about your past failures and sending us a link to the story.

GRBL Compatible Arduino CNC Shield

July 28, 2013 by Mike Szczys 33 Comments

By the time you get to the point in a home CNC build where you’re adding control electronics you may be ready for the simplest means to an end possible. In that case, grab your Arduino and heat up that etching solution to make your own GRBL compatible shield.

This familiar footprint manages to contain everything you need for a three-axis machine. The purple boards slotted into the pairs of SIL headers are Pololu Stepper motor drivers. Going this route makes replacing a burnt out chip as easy as plugging in a new module. The terminal block in the center feeds the higher voltage rail necessary for driving the motors. The DIL header on the right breaks out all of the connections to the limiting switches (two for each axis), spindle and coolant control, as well as three buttons for pause, resume, and abort. There’s even a header for SPI making it easier to add custom hardware if necessary.

This is a dual-layer board which may not be ideal for your own fabrication process. [Bert Kruger] posted his Gerber files for download if you want to put in a small run with OSH Park or a similar service.