Retrotechtacular: Häfla Hammerforge Healed

Visit any renaissance fair across the United States this fall and you’ll undoubtedly find a blacksmith. He’ll be sweating away in a tent, pounding on a piece of glowing steel set against an anvil. While the practice of the single blacksmith endures today, high-production ‘works of days past required increasing amounts of muscle. The more tireless the muscle, the better. The manual efforts of the blacksmith were replaced by huge hammers, and the blacksmith needed only to turn the piece between impressions and maintain a healthy respect for the awesome crushing power of the machine.

Last week, blacksmith enthusiasts completed restoration work on the Häfla hammer in Finspang, Sweden. The 333 year old hydraulic hammer hadn’t been used since 1924, when operations ceased at the Häfla Hammerforge. The ‘works was built in 1682 and used the German method of forging, which had been introduced to Sweden in the 1500s. Steel production was revolutionized in the 1800s by the Bessemer process, which resulted in a much stronger product. Continue reading “Retrotechtacular: Häfla Hammerforge Healed”

Retrotechtacular: The Hammond Novachord

Just when we thought we’d heard of all the cool early synthesizers, a tipster rattled our jar with news that someone completely restored a Novachord. These spinet piano-shaped prototypical synthesizers were made by Hammond for only four years. About a thousand of them were built before sales sagged and parts became scarce in 1942. It is estimated that only 200 or so are still around today.

The Novachord’s sounds are generated by a bank of twelve monostable vacuum tube oscillators. Each one is tuned to a pitch of the chromatic scale in what is called divide-down architecture. [Hammond] and his co-creators [John Hanert] and [C.N. Williams] used the property of dividing a frequency in half to generate the same tone, but one octave lower. This design means that all 72 notes can be played at the same time. Adjustable formant filters shape the often otherworldly sounds, which are then passed through flexible tube-based envelopes.

[Phil] knew it would be a big job to restore a Novachord in any condition. Thousands of passive components all had to be replaced. The cabinet bore all the hallmarks of a well-used parlor instrument—water rings from cocktails, scratches, and cigarette burns galore. [Phil] says that woodworking really isn’t his thing, but he did an outstanding job nonetheless of sanding every nook and cranny and applying several coats of stain. There are tons of drool-inducing pictures on his project site, and several clips of [Phil] really putting it through its paces.

Thanks for the tip, [Mike]!

Retrotechtacular is a weekly column featuring hacks, technology, and kitsch from ages of yore. Help keep it fresh by sending in your ideas for future installments.

Retrotechtacular: One Does Not Simply String Up a Half-Million VDC Transmission Line

It takes strong and determined population to build a lasting civilization. If the civilization includes electricity and the inhabitants live in a hilly place with an often-unforgiving climate, the required strength and determination increases proportionally. Such is the case of the gentlemen who strung up the first half-million VDC transmission line across New Zealand, connecting the country’s two main islands.

Construction for the line known as the HVDC Inter-Island link began in 1961. It starts at the Benmore hydroelectric plant on the south island and runs north to Cook Strait via overhead cables. Then it travels 40km underwater to the north island and ends near Wellington. This is the kind of infrastructure project that required smaller, preliminary infrastructure projects. Hundreds of miles of New Zealand countryside had to be surveyed before breaking ground for the first tower support hole. In order to transport the materials and maintain the towers, some 270 miles of road were laid and ten bridges were built. Fifteen camps were set up to house the workers.

The country’s hilly terrain and high winds made the project even more challenging. But as you’ll see, these men were practically unfazed. They sent bundles of steel across steep canyons on zip lines and hand-walked wire haulage rope across gullies because they couldn’t otherwise do their job. Six of these men could erect a tower within a few hours, which the filmmakers prove with a cool time-lapse sequence.

Splicing the mile-long conductors is done with 100-ton compressors. Each connection is covered with steel sleeve that must be centered across the joint for optimum transmission. How did they check this? By taking a bunch of x-rays with a portable cesium-137 source.

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Retrotechtacular: Robots, Robots Everywhere, with Kitschy Pronunciation

One of the great things about the human intellect is that we have the ability to build machines of varying complexity to do our bidding. As a major proponent of technology, the Chevrolet automobile corporation once dreamed of a future where the American housewife’s most mundane tasks are handled with the push of a button—one that sets a robot butler into action.

Chevy shows us what this future might look like in this short film, which they presented at the 1940 World’s Fair. A housewife’s faithful ‘robot’, pronounced throughout the picture as ‘robe-it’, has gone on the fritz. Naturally, she calls for a repairman. We see from the console controller that Roll-Oh the Robe-it can take care of all kinds of housewifely duties: he can answer the door and the phone, wash dishes, clean house, make beds, fetch hats, get dinner, and fix the furnace (and only the furnace). And that SCRAM! function? That’s never explained. We like to think it has to do with getting kids off the lawn, or could be used in conjunction with ‘get door’ to chase away would-be burglars. We get a glimpse of this when Roll-Oh answers the door and scares the daylights out of a young [Gary Sinise*] delivering flowers in a cop uniform.

Roll-Oh’s upper limbs have several Swiss Army knife-like implements in them. He uses a sharp one to cut the ribbon off of the flower box. Upon seeing the flowers, he gives them a gentle misting with his sprayer attachment. Dropped petals are no problem for Roll-Oh. He promptly vacuums them up from the thin industrial sound stage carpet with his big metal feet. Roll-Oh is then tasked with getting dinner. This amounts to him painstakingly opening a couple of cans and lighting candles with the torch hidden in his face.

While Roll-Oh the large ductwork butler is only a dream, Chevy wants you to know that smaller robe-its are all around us already. They’re regulating the heat in our stoves, browning our bread without burning it, and brewing our coffee in cool double-globe glass percolators. These tiny servants are capable of performing other tasks, like shutting off machinery when humans are too close, or sensing heat and engaging fire suppression systems. There is brief mention of something called the Petomat, an automatic dog feeding system which is essentially a bowl of food hidden in a latched box. The latch opens rather violently when the alarm clock connected to it goes off.

Robe-its are also performing more serious tasks, like keeping airplanes level and headed in the right direction. Of course, they’re also abundant in Chevrolet automobiles. A small one in the carburetor administers the proper mix of “gasoline calories and fresh air vitamins” to the engine. It’s rare to get to this level of technical detail, you know. Others watch over the spark, the intake manifold, and the voltage regulation. Up in the cab, friendly robe-its will happily traverse the AM dial at the push of a pre-set.

*Probably not actually [Gary Sinise].

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Retrotechtacular: The Trautonium Was Elemental to Electronic Music

Electrical engineer and music enthusiast [Freidrich Trautwein] was dissatisfied. He believed that the equal tempered scale of the piano limited a player’s room for expression. And so in 1930, [Trautwein] and an accomplished pianist named [Oskar Sala] began work on an electro-mechanical instrument that would bring the glissando of the string section’s fretless fingerboards to the keyboard player. [Trautwein] called his creation the Trautonium.

Sound is produced in the instrument by sawtooth frequency generators. It is then passed through filters and manipulated by the resistive string-based manuals. Frequency and intonation are varied relative to the position of the player’s finger along a length of non-conductive string and to the amount of pressure applied. This resistive string is suspended above a conductive metal strip between a pair of posts. A small voltage is applied to the posts so that when the string touches the metal strip below, the player manipulates a voltage-controlled oscillator. A series of metal tongues, also non-conductive, hover above the string. These are placed at scale intervals and can be used like keys.

This early synthesizer is capable of producing many kinds of sounds, from crisp chirps to wet, slapping sounds and everything in between. In fact, all of the sound effects in Alfred Hitchcock’s thriller The Birds were produced on a modified Trautonium by the instrument’s one and only master, [Oskar Sala]. He went on to score hundreds of films by watching them with the Trautonium at his fingertips, recording and layering his compositions into an eerie wall of sound.

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Retrotechtacular: Fantastic Backyard Inventions of Yore

News corporation [British Pathé] created many newsreels and documentaries throughout their 60-year history. Recently, the company released scores of films from their archives and put them on the internet. Here is a delightful collection of short films they created that highlight strange and wonderful inventions in various fields, including transportation and communication.

One of the standout inventions is the Dynasphere, a mono-wheeled vehicle that probably deserves its own week in the Retrotechtacular spotlight. There are a couple of pedal-powered planes that may have inspired the Gossamer Condor, and a hover scooter that resembles an air hockey striker and doubles as a leaf blower. In another film, a man drives a Vespa to the banks of the Thames and parks it. He pulls a fin down from each side of the scooter, turning it into a seafaring craft. When he snaps his fingers, a cute girl appears from somewhere just outside the frame. She climbs on the back, and they take off across the water.

The average running time of these films is about two minutes. Some of them are much shorter, prompting many questions. Fortunately, most of the video descriptions have links with more information about these marvelous inventions. Almost all of the inventors in these films show a complete disregard for safety, but nearly everyone involved seems to be having the time of their lives.

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Retrotechtacular: Coopering Guinness Barrels by Hand

For almost exactly 200 years, the Guinness brewery in Dublin, Ireland employed extremely skilled craftsmen to shape and construct wooden casks by hand. These men were called coopers, and plying their trade required several years of apprenticeship. The cooperage was a kind of closed society as many of the positions were passed down through generations of families. With the rise of aluminium and then stainless steel barrels in the late 1950s, the master coopers of Guinness became a dying breed.

Almost every step of the coopering process shown in this film is done without any kind of precise measurement. A master cooper like [Dick Flanagan] here needs only his eyes and his practiced judgment. His barrels start out as oak planks called ‘staves’ that have been drying in racks for at least two years. A cooper selects the staves that strike his fancy and he saws off the ends. This seems to be the only part of the process where a power tool is used.

The cooper shapes each stave by hand with axe and adze so that its ends are tapered just so. Once he has shaped enough of them to make a barrel, he arranges them in a cylinder around the inside of a metal band known as a hoop. The bound staves are steamed for half an hour to make them pliable enough for shaping.

After steaming, the splayed end of the staves are bound with wire rope to pull them close enough together that a hoop can be fitted over them. The inside of the cask is then charred with burning oak shavings, a process that seals the wood and removes its acidity. After this, the ends are sanded and the bunghole is drilled.

For each barrel, the cooper crafts a custom set of hoops. These are installed after the outside of the barrel has been shaved smooth. Finally, the heads that cap each end of the cask are made from more oak staves held together with dowel rods. This is the only time the cooper uses a tool to measure anything, and he does so to achieve the proper circumference on the heads. He bevels the edges so the heads will fit into bored-out grooves in the cask walls. Once they’re seated, the keg is ready for dark, rich stout.

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