Making Things Square In Three Dimensions

Measure twice, cut once is excellent advice when building anything, from carpentry to metalworking. While this adage will certainly save a lot of headache, mistakes, and wasted material, it will only get you part of the way to constructing something that is true and square, whether that’s building a shelf, a piece of furniture, or an entire house. [PliskinAJ] demonstrates a few techniques to making things like this as square as possible, in all three dimensions.

The first method for squaring a workpiece is one most of us are familiar with, which is measuring the diagonals. This can be done with measuring tape or string and ensures that if the diagonals are equal lengths, the workpiece is square. That only gets it situated in two dimensions, though. To ensure it’s not saddle-shaped or twisted, a little more effort is required. [PliskinAJ] is focused more on welding so his solutions involve making sure the welding tables are perfectly flat and level. For larger workpieces it’s also not good enough to assume the floor is flat, either, and the solution here is to minimize the amount of contact it has with the surface by using something like jack stands or other adjustable supports.

There are a few other tips in this guide, including the use of strategic tack welds to act as pivot points and, of course, selecting good stock to build from in the first place, whether that’s lumber or metal. Good design is a factor as well. We’ve also featured a few other articles on accuracy and precision,

Square-Wheeled Bike Is Actually An Amazing Tracked Build

The invention of the wheel is considered one of the crowning achievements of early humanity. Squares don’t roll, after all. [The Q] decided to build a square-wheeled bike anyway, with a neat tracked setup that makes for an awesome visual gag.

The wheels are made out of C-angle steel, making them both stout and incredibly heavy. While they don’t really need the additional structure for strength, they feature spokes which mount a central hub for attaching the “wheels” to a bicycle axle. The squares aren’t designed to roll, though. Instead, they are fitted with gears and rollers, upon which a track made of bicycle chain and tires is fitted. When the rider pedals, this turns the track, propelling the bike along. Cleverly, the track mechanism is neatly hidden by some framing, confusing passers-by.

The riding experience is noisy, thanks to the tracks. There’s also plenty of rolling resistance. It’s unlikely bikes like these will become mainstream transport anytime soon, nor will you see them at the velodrome. Regardless, it’s certainly a great way to turn heads at the park.

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There’s Nothing Square About This Rectangular Guitar

We kind of already knew this, but it seems that [Uri Tuchman] really can build absolutely anything. This fall, he was asked to compete in the Great Guitar Build-Off competition, which involves a fully-customizable kit guitar sent to each entrant as a starting point. In order to allow for maximum creativity, the wooden parts like the body and the headstock are square. And quite creatively, [Uri] kept them that way. Square, that is.

While yes, the body rising out of the squareness is in fact a Les Paul profile, there are a ton of details that make this a [Uri Tuchman] instead. For starters, everything is square, beginning with the custom brass knobs for the volume and tone potentiometers. We’re not sure if it came with humbuckers, but that sure is a happy accident if so. If only the neck blank had been square, [Uri] could have made a lap steel. Once it was finished, [Uri] took it to a luthier to have it set up, fine-tuned, and assessed for quality. Of course, it passed with flying Vs colors.

There are plenty of other [Uri] hallmarks, like the bird on the neck plate, and another hiding in the hand-drawn and hand-carved pickguard, so be sure to check it out after the break.

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Hackaday Links: September 17, 2017


Mergers and acquisitions? Not this time. Lattice Semiconductor would have been bought by Canyon Bridge — a private equity firm backed by the Chinese government — for $1.3B. This deal was shut down by the US government because of national security concerns.

[Jan] is the Internet’s expert in doing synths on single chips, and now he has something pretty cool. It’s a breadboard synth with MIDI and CV input. Basically, what we’re looking at is [Jan]’s CVS-01 chip for a DCO, DCF, and DCA), a KL5 chip for an LFO, and an envelope chip. Tie everything together with a two-octave captouch keyboard, and you have a complete synthesizer on a breadboard.

As an aside relating to the above, does anyone know what the cool kids are using for a CV/Gate keyboard controller these days? Modular synths are making a comeback, but it looks like everyone is running a MIDI keyboard into a MIDI-CV converter. It seems like there should be a –simple, cheap– controller with quarter-inch jacks labeled CV and Gate. Any suggestions?

World leaders are tweeting. The Canadian PM is awesome and likes Dark Castle.

Way back in July, Square, the ‘POS terminal on an iPad’ company posted some data on Twitter. Apparently, fidget spinner sales peaked during the last week of May, and were declining through the first few weeks of summer. Is this proof the fidget spinner fad was dead by August? I have an alternate hypothesis: fidget spinner sales are tied to middle schoolers, and sales started dropping at the beginning of summer vacation. We need more data, so if some of you could retweet this, that would be awesome.

Remember [Peter Sripol], the guy building an ultralight in his basement? This is going to be a five- or six-part video build log, and part three came out this week. This video features the installation of the control surfaces, the application of turnbuckles, and hardware that is far too expensive for what it actually is.

Sometimes Square Is Square: Basic Machinist Skills

Is it possible to make an entertaining video about turning a cube of aluminum into a slightly cubier cube? As it turns out, yes it is, and you might even learn something along with the sight gags and inside jokes if you watch [This Old Tony] cover the basics of squaring up stock.

Whether you’re working in wood or metal, starting with faces that are flat, smooth and perpendicular is the key to quality results. [Tony] is primarily a machinist, so he works with a nice billet of aluminum and goes through some of the fundamental skills every metalworker needs to know. When you’re working down to the thousandths of an inch it’s easy to foul up, and tricks such as using a ball bearing between the vise jaws and the stock to prevent canting are critical skills. He covers tramming the mill, selecting which faces to cut and in which order, and ways to check your work on the surface plate and make any corrections if and when things go wrong. Look for cameos by fellow machinist [Abom79] and [Stefan Gotteswinter], including one with [Stefan] in a very compromising position. But a ball in a vise and no [AvE] reference? C’mon!

[Tony] makes a potentially tedious subject pretty entertaining by keeping things light, and we appreciate both the humor and attention to detail. He’s turned out some great videos that we’ve covered before, like making your own springs or a shop-built boring head, and his stuff is really worth checking out.

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Rainy Day Fun By Calculating Pi

If you need a truly random event generator, just wait till your next rainstorm. Whether any given spot on the ground is hit by a drop at a particular time is anyone’s guess, and such randomness is key to this simple rig that estimates the value of pi using raindrop sensors.

You may recall [AlphaPhoenix]’s recent electroshock Settlers of Catan expeditor. The idea with this less shocking build is to estimate the value of pi using the ratio of the area of a square sensor to a circular one. Simple piezo transducers serve as impact sensors that feed an Arduino and count the relative number of raindrops hitting the sensors. In the first video below, we see that as more data accumulates, the Arduino’s estimate of pi eventually converges on the well-known 3.14159 value. The second video has details of the math behind the method, plus a discussion of the real-world problems that cropped up during testing — turns out that waterproofing and grounding were both key to noise-free data from the sensor pads.

In the end, [AlphaPhoenix] isn’t proving anything new, but we like the method here and can see applications for it. What about using such sensors to detect individual popcorn kernels popping to demonstrate the Gaussian distribution? We also can’t help but think of other ways to measure raindrops; how about strain gauges that weigh the rainwater as it accumulates differentially in square and circular containers? Share your ideas in the comments below.

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Make Math Real With This Analog Multiplier Primer

Remember learning all about functions in algebra? Neither do we. Oh sure, most of us remember linear plots and the magic of understanding y=mx+b for the first time. But a lot of us managed to slide by with only a tenuous grasp of more complex functions like exponentials and conic sections. Luckily the functionally challenged among us can bolster their understanding with this demonstration using analog multipliers and op amps.

[devttys0]’s video tutorial is a great primer on analog multipliers and their many uses. Starting with a simple example that multiplies two input voltages together, he goes on to show circuits that output both the square and the cube of an input voltage. Seeing the output waveform of the cube of a ramped input voltage was what nailed the concept for us and transported us back to those seemingly wasted hours in algebra class many years ago. Further refinements by the addition of an op amp yield a circuit that outputs the square root of an input voltage, and eventually lead to a voltage controlled resistor that can attenuate an input signal depending on its voltage. Pretty powerful stuff for just a few chips.

The chip behind [devttys0]’s primer is the Analog Devices AD633, a pretty handy chip to have around. For more on this chip, check out [Bil Herd]’s post on analog computing.

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