The Forgotten Art of Riveted Structures

If you are in the habit of seeking out abandoned railways, you may have stood in the shadow of more than one Victorian iron bridge. Massive in construction, these structures have proved to be extremely robust, with many of them still in excellent condition even after years of neglect.

A handsome riveted railway bridge, over the River Avon near Stratford-upon-Avon, UK.
A handsome riveted railway bridge, over the River Avon near Stratford-upon-Avon, UK.

When you examine them closely, an immediate difference emerges between them and any modern counterparts, unlike almost all similar metalwork created today they contain no welded joints. Arc welders like reliable electrical supplies were many decades away when they were constructed, so instead they are held together with hundreds of massive rivets. They would have been prefabricated in sections and transported to the site, where they would have been assembled by a riveting gang with a portable forge.

 

So for an audience in 2018, what is a rivet? If you’ve immediately thought of a pop rivet then it shares the function of joining two sheets of material by pulling them tightly together, but differs completely in its construction. These rivets start life as pieces of steel bar formed into pins with one end formed into a mushroom-style dome, probably in a hot drop-forging process.

A rivet is heated to red-hot, then placed through pre-aligned holes in the sheets to be joined, and its straight end is hammered to a mushroom shape to match the domed end. The rivet then cools down and contracts, putting it under tension and drawing the two sheets together very tightly. Tightly enough in fact that it can form a seal against water or high-pressure steam, as shown by iron rivets being used in the construction of ships, or high-pressure boilers. How is this possible? Let’s take a look!

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When Is Wrought Iron Not Wrought Iron?

I grew up with a blacksmith for a parent, and thus almost every metalworking processes seems entirely normal to have as part of everyday life throughout my childhood. There seemed to be nothing we owned that couldn’t be either made or repaired with the application of a bit of welded steel. Children of blacksmiths grow up with a set of innate heavy hardware hacker or maker skills that few other young people acquire at that age. You know almost from birth that you should always look away from the arc when dad is welding, and you also probably have a couple of dictionary definitions ready to roll off the tongue.

The first is easy enough, farrier. A farrier makes and fits horseshoes. Some blacksmiths are farriers, many aren’t. Sorry, my dad made architectural ironwork for upmarket houses in London when he wasn’t making improvised toys for me and my sisters, he didn’t shoe horses. Next question.

The second is a bit surprising. Wrought iron. My dad didn’t make wrought iron.

But… Hang on, you say, don’t blacksmiths make wrought iron? At which point the floodgates open if you are talking to a blacksmith, and you receive the Wrought Iron Lecture.

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Making a Gun Without a 3D Printer

Around four years ago the world was up in arms over the first gun to be 3D printed. The hype was largely due to the fact that most people don’t understand how easy it is to build a gun without a 3D printer. To that end, you don’t even need access to metal stock, as [FarmCraft101] shows us with this gun made out of melted aluminum cans.

The build starts off by melting over 200 cans down into metal ingots, and then constructing a mold for the gun’s lower. This is the part that is legally regulated (at least in the US), and all other parts of a gun can be purchased without any special considerations. Once the aluminum is poured into the mold, the rough receiver heads over to the machine shop for finishing.

This build is fascinating, both from a machinist’s and blacksmith’s point-of-view and also as a reality check for how easy it is to build a firearm from scratch provided the correct tools are available. Of course, we don’t need to worry about the world being taken over by hoards of angry machinists wielding unlicensed firearms. There’s a lot of time and effort that goes into these builds and even then they won’t all be of the highest quality. Even the first 3D printed guns only fired a handful of times before becoming unusable, so it seems like any homemade firearm, regardless of manufacturing method, has substantial drawbacks.

Thanks to [Rey] for the tip!

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Blacksmith’s Junkyard Power Hammer Packs a Punch

Any way you look at it, blacksmithing is a punishing trade. Heavy tools, a red-hot forge, flying sparks, and searing metal all exact a toll on the smith’s body unless precautions are taken. After proper safety equipment and good training, a blacksmith may want to invest is power hammer to replace at least some of the heavy hammer work needed to shape hot metal.

Power hammers aren’t cheap, though, which is why [70kirkster] built one from an old engine block. You’ve got to admire the junkyard feel of this thing; it’s almost nothing but scrap. The engine block is a straight-6 from an old Ford pickup stripped of everything but the crankshaft and one piston. An electric motor spins the crankshaft and moves the hammer against the anvil through connecting rods and a trip arm fashioned from a trailer leaf spring. Everything looks super solid and the hammer hits hard; the videos below tell the tale of the build and show the hammer in action. Not bad for $100 out-of-pocket.

Blacksmithing is one of those dark arts that really deserves to have more adherents. The barriers to entry can be high, but the rewards are great. Looking to get started on the cheap? Then check out [Bil Herd]’s guide to hacking together a backyard smithy.

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Forming Voltron’s Blazing Sword For Real

Activate interlock! Dynotherms connected! Infracells up! Mega thrusters are go! If you grew up in the 80’s you undoubtedly know that quote means it’s time to form Voltron. The 1984 Lion Force Voltron series has shown an incredible amount of staying power. These 5 lions have come together to form no less than 3 reboot series, the most recent coming out just this month from Dreamworks and Netflix.

[Matt and Kerry Stagmer], blacksmiths for the Man at Arms web series haven’t forgotten Voltron either. Every episode of the original series ended with the mighty robot defeating enemies using an iconic blazing sword. While they might not be able to bring us 5 robot lions which join together to form one mega robot, [Matt and Kerry] can bring us a human sized version of Voltron’s sword (YouTube).

Starting with a high-resolution image of a toy version of the sword, [Matt] traced the outline. The shape was sent over to a plasma cutter. Rather than cut one sword, two outlines were cut. One in 1/4″ steel, the other in 3/16″. A CNC was used to cut grooves in the 1/4″ section. These grooves became the manifold for propane gas jets. Separate jets were cut around the perimeter of the sword. With this complete, the two pieces were carefully TIG welded together.

This sword isn’t all prop and no chop. The upper sections were heat-treated and sharpened to a razor edge. We won’t go so far as to call this practical. It wields more like an ax than a sword. At the end of the day it doesn’t really matter though – this blazing sword is completely awesome.

Blacksmith Forge Made From the Bathroom Sink

The sweltering heat had finally moved on and Giant Tick season was coming to a close (not kidding, they are HUGE here), when I decided to fire up my hacked together blacksmith forge made out of an old bathroom sink and aquarium stand.

In the age-old formula I needed to supply an air source to a fuel to create enough heat to make iron malleable. I got the idea that this particular bathroom sink might be a good candidate for a fire bowl after I banged my shin with it and then cursed at it. It was clearly made of cast iron and as proof it was clearly unfazed by my tirade of words which I hope my son has learned from the Internet and not from listening to me remodel the bathroom.

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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”