[This Old Tony] was cleaning up his metal shop after his yearly flirtation with woodworking when he found himself hankering for a nice coffee. He was, however, completely without a coffee making apparatus. We imagine there was a hasty round of consulting with his inanimate friends [Optimus Prime] and [Stefan Gotteswinter Brush] before he decided the only logical option was to make his own.
So, he brought out two chunks of aluminum from somewhere in his shop, modeled up his plan in SolidWorks, and got to work. It was designed to be a moka style espresso pot sized around both the size of stock he had, and three purchased parts: the gasket, funnel, and filter. The base and top were cut on a combination of lathe and mill. He had some good tips on working with deep thin walled parts. He also used his CNC to cut out some parts, like the lid and handle. The spout was interesting, as it was made by building up a glob of metal using a welder and then shaped afterward.
As usual the video is of [This Old Tony]’s exceptional quality. After quite a lot of work he rinsed out most of the metal chips and WD40, packed it with coffee, and put it on the stove. Success! It wasn’t long before the black stuff was bubbling into the top chamber ready for consumption.
He was looking enviously at the squareness comparator that [Tom Lipton] had made when somone on Instagram posted a photo of the comparator they use every day. [Stefan] loved the design and set out to build one of his own. He copied it shamelessly, made a set of drawings, and got to work.
[Stefan]’s videos are always a trove of good machine shop habits and skills. He always shows how being careful, patient, and doing things the right way can result in really astoundingly precise work out of a home machine shop. The workmanship is beautiful and his knack for machining is apparent throughout. We chuckled at one section where he informed the viewer that you could break a tap on the mill when tapping under power if you bottom out. To avoid this he stopped at a distance he felt was safe: 0.5 mm away.
The construction and finishing complete, [Stefan] shows how to use the comparator at the end of the video, viewable after the break.
Newton’s Cradle is thought of as the most elegant of executive desk toys. But that 20th-century dinosaur just got run off the road as [Ben Katz]’s Furuta pendulum streaks past in the fast lane, flipping the bird and heralding a new king of desk adornments.
This Furata pendulum has wonderfully smooth movement. You can watch it go through its dance in the video after the break. Obviously you agree that this is the desk objet d’art for the modern titan of industry (geek). Just don’t stop at watching it in action. The best part is the build log that [Ben] put together — this project has a little bit of everything!
“I wasted a weekend learning why elemental bismuth is not commonly used for metal parts.“
It’s a fair assessment of his time spent growing unspectacular bismuth crystals, casting a bismuth cylinder that cracked, and machining bismuth only to be left with a very rough finish. But even though he admits the exercise was unsuccessful, he does provide us with a fascinating look at the physical properties of the element.
This is what [David] wanted to make. Alchemist-hp + Richard Bartz with focus stack. (Own work) [CC BY-SA 3.0], via Wikimedia Commons
Bismuth is one of those elements you pass by in your school chemistry lessons, it has applications in machining alloys and as a lead replacement but most of us have never knowingly encountered it in the real world. It’s one of the heavy metals, below antimony and to the right of lead on the Periodic Table. Curious schoolchildren may have heard that like water it expands on solidifying or that it is diamagnetic, and most of us have probably seen spectacular pictures of its crystals coated in colourful iridescent oxides.
It was a Hackaday story about these crystals that attracted [David] to the metal. It has a low enough melting point – 271.5 °C – that it can be liquified on a domestic stove, so mindful of his marital harmony should he destroy any kitchen appliances he bought a cheap electric ring from Amazon to go with his bismuth ingot. and set to work.
His first discovery was that cheap electric rings outdoors aren’t very effective metallurgy furnaces. Relocating to the kitchen and risking spousal wrath, he did eventually melt his bismuth and pick off the top layer once it had resolidified, to reveal some crystals.
These are the bismuth crystals he made.
Unfortunately for him, instead of spectacular colors and huge crystals, the sight that greeted him was one of little brilliance. Small grey crystals with no iridescence. It seems the beautiful samples are made by a very slow cooling of the liquid bismuth, followed by a quick pouring off of the remaining molten metal. Future efforts, he assures us, will involve sand-insulated molds and careful temperature monitoring.
Undeterred, he continued with his stock of bismuth and embarked on the creation of a cylinder. Early efforts with a clay mold resulted in cracked cylinders, so in desperation he cast the entirety of the metal in an aluminium baking tray and cut the resulting ingot to a rough piece of stock for turning.
Poor finish on machined bismuth.
With the bismuth in the lathe, he then came face to face with what he alluded to in his conclusion above, why machined bismuth parts aren’t something you’ll encounter. His cylinder came out with significantly rough patches on the surface, because bismuth is both crystalline and brittle. He suggests improvements could be made if the metal could be solidified with fewer crystals, but it’s obvious that elemental bismuth on its own is not a winner in the turning stakes.
We suggest you take a look at [David]’s write-up. It may be presented as a Fail of The Week here, but in fact it’s more of a succession of experiments that didn’t work than an unmitigated disaster. The result is an interesting and well-documented read that we’re sure most Hackaday readers will gain something from.
Fail of the Week is a Hackaday column which celebrates failure as a learning tool. Help keep the fun rolling by writing about your own failures and sending us a link to the story -- or sending in links to fail write ups you find in your Internet travels.
If you’re interested in making things (and since you’re reading this, we’re going to assume you are), you’ve almost certainly felt a desire to make metal parts. 3D printers are great, but have a lot of drawbacks: limited material options, lack of precision, and long printing times. If you want metal parts that adhere to even moderately tight tolerances, a milling machine is your only practical option. There is, after all, a very good reason that they’re essential to manufacturing.
However, it can be difficult to know where to start for the hobbyist who doesn’t have machining experience. What kind of milling machine should you get? Should you buy new or used? What the heck is 3-phase power, and can you get it? These questions, among many others, can be positively overwhelming to the uninitiated. Luckily, we — your friends at Hackaday — are here to help give you some direction. So, if you’re ready to learn, then read on! Already an expert? Leave some tips of your own in the comments!
What happens when you break a tap or a bolt in a component whose price tag sits in the tens of thousands. Just drilling it out and throwing in a nut insert stops being acceptable. Is there a way to remove the tap without damaging the master part at all?
Broken tap stuck in the hole it was threading
Well, that’s where [Tom Grafton] of Jerry’s Broken Drill and Tap comes in. He’s here to remove taps and chew bubblegum, and he’s definitely chewing bubble gum loudly the whole time. His primary work horse is a Metal Disintegration Machine.
A MDM is basically half of a typical wire EDM set-up. In EDM you used an electrode to punch a hole through the material. Then you thread a wire through the hole, thread it through a sometimes startling array of pulleys, and get going.
[Tom] used the MDM with an appropriately sized electrode to precisely disintegrate the middle of the tap out. After that it’s some careful work with a specially machined magnetic chisel. A quick chase of the threads with a tap and it’s back to the customer.
As you can see in the video after the break, the end result is a threaded hole that’s so indistinguishable from the rest he has to mark which one it was; presumably so the customer doesn’t forget why they’re paying him.
A corollary to Godwin’s Law ought to be that any Hackaday post that mentions Nikola Tesla will have a long and colorful comment thread. We hope this one does too, but with any luck it’ll concentrate on the engineering behind this tiny custom-built Telsa turbine.
For those not familiar with Mr. Tesla’s favorite invention, the turbine is a super-efficient design that has no blades, relying instead on smooth, closely spaced discs that get dragged along by the friction of a moving fluid. [johnnyq90]’s micro version of the turbine is a very accomplished feat of machining. Although at first the build appears a bit janky, as it progresses we see some real craftsmanship – if you ever doubt that soda can aluminum can be turned, watch the video below. The precision 25mm rotor goes into a CNC machined aluminum housing; the way the turned cover snaps onto the housing is oddly satisfying. It looks like the only off-the-shelf parts are the rotor bearings; everything else is scratch-made. The second video ends with a test spool-up that sounds pretty good. We can’t wait for part 3 to find out how fast this turbine can turn.
![This is what [David] wanted to make. Alchemist-hp + Richard Bartz with focus stack. (Own work) [CC BY-SA 3.0], via Wikimedia Commons](https://hackaday.com/wp-content/uploads/2016/08/bi-crystal.jpg)
Fail of the Week is a Hackaday column which celebrates failure as a learning tool. Help keep the fun rolling by writing about your own failures and 
