Hackamajig Etsy store

Dear everybody,

We’re back now, and we’ve reopened our Etsy storefront featuring hand-made nerdcraft…

Eardrives! (Yes, really. Store up to 32 gigabytes per ear using standard microSD cards.)

eardrive earrings (add your own flash cards)

High-Precision Earrings! (Again, yes, really. There was an incident involving an antique stereo microscope, and… never mind. Anyway, they’re shiny!)

Precision earrings made from tiny, precise straightedges with 0.01-inch and 0.02-centimeter graduations

Please stop by our shop for a visit.

Cheers — Stochastic.

Hackamajig is moving to New Orleans in 2013

Hi all,

Hackamajig is owned by Kaben Nanlohy (kaben dot nanlohy at gmail dot com). Hackamajig has been temporarily shut down while we move the business from Lansing, Michigan to New Orleans, Louisiana. We will reopen when the move is complete. Thanks for visiting!

— stochastic

The process of locating holes with a CNC machine is copiously supplied with opportunities to totally mess everything up

Okay, here’s what happens:

You’ve got yourself a nifty robotic doodad called a “CNC milling machine” which cuts through hefty chunks of metal like butter… if you don’t mess up. If you do mess up, there are horrible grinding sounds, the smattering of “ping” and “tinkle” sounds as important bits and pieces shatter and fly into the walls (this is why safety glasses were invented), and long gouges in said metal chunks if you’re lucky, and in your nifty robotic metal-carving machine if you’re not.

We’ve learned that about 3:00 a.m. — at the latest — is when we start to make lots of mistakes. The other night we broke three tool bits in the space of ten minutes before it occurred to us that, hey, we were tired! and we were having difficulty concentrating!

Two of these bits were buried the in material we were trying to carve. One bit was embedded in the machine itself. Actually, it was embedded in aluminum plating which we’d placed between the work and the machine, because we just knew we were going to mess up badly at some point, and we wanted to protect the machine from ourselves. How prescient of us!

These ten minutes cost us about $30 in materials and tools, which is not much. It also ruined about eight hours of work, which was painful.

Now, we know that everybody does this when they learn how to use these machines, which is why we’ve been taking precautions to protect our investment, and why we’ve been taking notes to help us study and address the mistakes. Here’s what we’ve learned so far:

  • A nice big friendly red PANIC button must at all times be within arm’s reach. This is known as the “emergency stop” button. The purpose of this button is to make all the moving parts stop moving exactly two milliseconds before the machine eats itself according to your careful directions. The timing is important here: any later, and you’ll leave horrible scars on your work or your milling machine; any earlier, and you won’t almost have a heart attack, which means you simply won’t learn anything from the experience. The almost heart attack is very important.
  • Each degree of freedom of movement provides your milling machine more ways to damage itself. Supposing p_x, p_y, and p_z are the probabilities that the machine will jam in the next ten minutes on the X-, Y-, or Z-axis, respectively; the probability that the machine will jam on at least one axis in the next ten minutes is 1-(1-p_x)*(1-p_y)*(1-p_y). Add more axes to make the problem worse. This is a horribly complicated way of saying that sensors absolutely must be installed to monitor the machine’s movement in each degree of freedom. Otherwise the machine will become lost, and as it no longer knows where its cutting tools are, it will begin to cry and wail and throw an embarrassing tantrum, and then have a meltdown very like a lost child in a department store. And people will stare accusingly at you and your poor machine, and you will feel like a lousy parent.
  • Find a way to automate the measuring of each milling tool’s length immediately after you lock it into the machine’s spindle. Otherwise, when you run out of coffee, and you swap-in a new milling tool, and you tell the machine how long the tool is, you will probably be wrong, and the machine will either carve pretty patterns in the air above your work, or it will try to carve pretty patterns in the table under your work. In the latter case, the machine will happily puncture your work and shatter your milling tool on the way to the table.
  • Find a way to automate the process of precisely locating your workpiece in your machine’s coordinate systems. For pretty much the same reason as above, in order to avoid pretty carvings in the table, punctured workpieces, and shattered tools.
  • Most CNC machine controllers have a single “probe” input. You will probably want to use both a “touch probe” to locate workpieces in machine coordinates, and a “tool touch-off switch” to measure the lengths of your tool bits. Find a way to permanently and concurrently connect both sensors to the single probe input. Otherwise, you will eventually run out of coffee, and you will plug in the wrong sensor. This means that the sensor that should be plugged in will be destroyed in slow motion. If it is the touch probe, it will neatly fold and crumple. If it is the switch, it will be run-through with a sharp tool bit.
  • Take the time to carefully write and test programs to automate as much of your work as possible. If you cannot automate a particular step, if you must perform that step manually, you can at least write code that tells your machine to tell future-you what to do, step by step, when future-you runs out of coffee.
  • Place a protective layer of sacrificial material on machine surfaces which the machine might be able to attack if it decides to eat itself. For example, we bolted an aluminum tooling plate to our milling table, and we consider this tooling plate to be replaceable and disposable, although we hope to not have to replace it any time soon. Sadly, this hope is already dashed, but at least our milling machine isn’t damaged.
  • Finally, when you run out of coffee, stop operating the milling machinery. Even if it isn’t particularly heavy. Ours sits on a little table, and we can easily pick it up and move it to another table, so we can hardly call it heavy. Nevertheless, the good desktop milling machines are capable of many of the same heavy-duty operations performed on much bigger machines that weigh several tons, and which occasionally eat people. So treat your little machine with the same respect you’d give to heavy machinery.

Although none of our machines have tried to eat us, we have experienced the rest of these mishaps. We expect to make many more rookie mistakes as we learn. We try to plan for such mistakes. Taking notes makes this much easier.

Okay, then, back to work…

Good night,


precision earrings

Today’s banner: the unexpected juxtaposition of two totally unrelated ideas: “distance-measuring instruments” and “adornments of the earlobes”, with the obvious result… precision earrings! And yes, if you’d like a pair, we’re selling them at our new Etsy site: hackamajig.etsy.com. These earrings are Hackamajig’s very first product.

If you’re wondering how they came to be, it’s because we use an old university-surplus stereo microscope.

To explain: we wished to visually measure minuscule things using said microscope, which, being old and university-surplus, lacks a built-in visual scale. Our inkjet-printed paper rulers proved too imprecise for measuring minuscule things. Moreover, we wished to measure minuscule things right now, as we are slaves to instant gratification, and as we possessed no high-precision ruler suitable for microscopy, we clearly had to make one. Immediately. So we grabbed a small chunk of aluminum and a sharp chunk of steel, and we (i.e., our Taig micromilling machine) scratched out lines a hundredth of an inch apart:

Here’s a closeup of the scribed lines:

One of us observed that this tiny ruler would make a great earring. Such an observation was inevitable, because we are geeks, and to us the word “bling” signifies “high-precision devices, preferably shiny”.

To complement the imperial high-precision earring, the second in the pair would of course need to be metric. So we found another chunk of aluminum, and we scratched out lines a hundredth of a centimeter apart:

We were curious to see whether we could do this reliably, so we made a second earring in 0.01-centimeter graduation.

So, yes, the work was repeatable. But sadly, without a microscope this 0.01-centimeter graduation looks like a single gray line:

But a 0.02-centimeter graduation can still be seen with the naked eye.

We estimate the accuracy of these high-precision earrings to be better than one half of one thousandth of an inch, traceable to standard Taig milling machine leadscrews.

— stochastic

3dp parts

Today’s banner: piles of nuts and bolts, and yes, we realize that this description, while accurate, is less than helpful. Read on for an explanation.

When we show people photographs or constructs from hackamajig, a common response is “I have no idea what I’m looking at. What the heck is this?” Which is sort of the point. In our stories and photos we try to bring you unexpected juxtapositions of disparate ideas, realized in ways that delight. These may take tangible shape as artwork, machines, mechanisms, metalworking, papercraft, and so on, or they may be stories, or ideas. But everything we bring to you shares this character: somebody made it, and we thought it was nifty or clever.

Another common reaction is “Ooh, shiny!” Which is also sort of the point.

Anyway, to explain what the heck you’re looking at: we were once the proud owners of a homemade 3-d printer, à la reprap.org and makerbot.com. It was a rather complex device. Somebody once commented “It would be fun if you were to completely dismantle it, and make little piles out of the components, and take pictures.” So we did. It was fun:

Don’t worry, we’ve making a new one. We plan to tell you more about it in the near future.

Here are some links to follow if you’d like to learn more about homemade 3-d printers. Analogous to a printer that makes two-dimensional images, designs, or words on paper, a three-dimensional printer makes three-dimensional objects, such as small sculptures or mechanisms:


Best wishes — stochastic


Today’s banner: long curls of aluminum swarf issued from a drilling operation on the lathe.

These were produced by a new 7/16″ drill bit. The drilling operation was quick, the bit requiring very little applied force. In fact, a large increase in force behind the bit results in only a moderate increase in the rate of material removal. This is characteristic of sharp tools, in general — and this is why sharp tools are easy to use.

Dull tools, of course, are characterized by frustration. Using a dull tool is a good way to make the tool duller. And that is why we have a good set of bits that have remained sharp for quite a long time. Of course, we have yet to master the art of sharpening bits. Especially the really tiny ones.

And since our machine work tends toward the small scale, we have a steadily-increasing supply of upside-down bits in our bit-cases (they’re upside to remind us that they’re dull). In our investigation into bit-sharpening methods we’ve encountered opinions held with fanatic conviction:

“A Drill Doctor is the way to go!”

“No, make your own sharpening jig!”

“Sharpening jigs are only good for practicing your sledgehammer technique.”

“When I was a boy we sharpened our bits by hand! Barefoot! In the snow, and uphill both ways!”

“Throw them away, and buy new ones from us! In bulk! Look, they’re shiny!”

“We’ll sharpen them for you. We charge only a modest fee…”

So, anyway, we have a nice wet-grinding wheel. If anyone knows how to use it, please drop us a line.

Best — stochastic.


Today’s banner: a disintegrated Bowden cable, an erstwhile component of the tensioning mechanism in our beloved squiggly-magnetic-dial-indicator stand thingy:

The squiggly-magnetic-dial-indicator stand was, in turn, part of our notatripod, formerly an integral chunk of our makeshift photo studio. This is what the indicator stand looks like now:

On one hand, we are no longer impressed by the design and construction of this device. On the other hand, it is highly likely that we have unknowingly abused the poor thing, and we mourn the loss of our notatripod — it was so very useful. On the third hand, we’re pretty sure we can fix it; but on the fourth hand, we wonder whether it will simply break again.

We seem to have run out of hands while we weren’t looking. (sigh)

Sleep well tonight — stochastic


Today’s banner: a centrifuge, about ten times as tall as the guy standing beside it. (But he’s only three inches high.)

And below is a bucket, with an attractively decorated lid (or at least it looks like a bucket):

It contains a thing. The thing looks electric:

Indeed, the thing has an electrical cord, dials, and what appears to be another thing that perhaps spins:

The bucket fits nicely on top of the electrical thing. It’s a tiny electric washing machine! Its name is “Wonder Washer“, an apparently unbranded Chinese product (not to be confused with “Wonder Wash“, which is a totally different product powered by the human arm).

We like the Wonder Washer because it’s so compact when stored, and it’s highly-portable. It works very well for small items (socks, underwear, washcloths, dishtowels, rags, …). It also works fairly well for T-shirts. It’s pretty much useless for anything more bulky, like sweaters, jeans, towels, or sheets. If you try to use this little washer to wash any of these big items, the little washer makes very sad groaning noises. Also, it’s kind of loud. Not terribly so, but loud enough that you can hear when it finishes washing, even if you’re in the next room. A full load of laundry is 8-10 liters:

A similarly-sized laundry centrifuge, shown below, works well with the tiny washing machine. This spin dryer is made by another company entirely — The Laundry Alternative, Inc (who also make the afore-mentioned human-arm-powered Wonder Wash, which is distinct from the Wonder Washer, whose name-similarity is confusing). This spin dryer is very quiet, and it works extremely well. You’ll still need to line-dry or tumble-dry your clothes after spinning in this device. But we’ve found that if you spin your clean wet clothing in this little centrifuge, and then finish drying on a clothesline or in the tumble dryer, they dry faster than after spin-drying in a standard washing machine.

We’ve photographed a little guy standing next to the spin dryer, in order to give you sense of scale. (But actually he’s only there for the fun of it. The spin dryer is not, in fact, sixty feet tall.):

Best wishes,



Today’s banner: our improvised photo studio, comprising a dinner table, a curtain rod, a desk lamp and two squiggly-headed floor lamps, two rolls of paper, and several tiny figurines cavorting on the equipment. No, no, please try to contain your envy, not everyone can have a setup this snazzy:

The figurines are fun but otherwise serve absolutely no purpose whatsoever, except maybe a kind of conspicuous consumption: “… our photo studio has a troupe of tiny acrobats that perform on the lighting equipment. They’re just for atmosphere. They help keep the mood light.”

Although the studio is improvised, it works so well that we’re keeping it.

Have a good night — stochastic.

impact crater

Today’s banner: an impact crater, steel having smashed into aluminum at the mind-numbing speed of — wait for it — zero. After we’ve center- or prick-punched a tiny indentation in the aluminum surface, this is what it looks like up close:

To make such an indentation, one carefully aligns the tip of a punch to the desired spot on the workpiece surface, and then carefully taps the other end of the punch with a small hammer. As in our previous blog posts, the black vertical lines in this image are the rules of an inkjet-printed millimeter ruler, presented for scale. As you can see from the crosshairs, we totally nailed it.

Here’s a closer image of another punch, which, again, we nailed:

Sleep well tonight — stochastic.