Fixing a Broken Bandsaw with a Custom Steel Part

When a large bandsaw broke down due to a cast iron part snapping in two, [Amr] took the opportunity to record the entire process of designing and creating a solid steel replacement for the broken part using a (non-CNC) mill and lathe.

For those of us unfamiliar with the process a machinist would go through to accomplish such a thing, the video is extremely educational; it can be sobering both to see how much design work happens before anything gets powered up, and just how much time and work goes into cutting and shaping some steel into what at first glance looks like a relatively uncomplicated part.

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Metal Magic: Heat Bluing Steel Clock Hands

Metalwork of any kind is fascinating stuff to watch. When the metalwork in question is in service of the clockmaker’s art, the ballgame changes completely. Tiny screws and precision gears are created with benchtop lathes and milling machines, and techniques for treating metals border on alchemy – like heat-bluing of steel clock hands for a custom-built clock.

If you have even a passing interest in metalwork and haven’t followed [Clickspring]’s YouTube channel, you don’t know what you’re missing. [Chris] has been documenting a museum-quality open-body clock build, and the amount of metalworking skill on display is amazing. In his latest video, he covers how he heat-blues steel to achieve a wonderful contrast to the brass and steel workings. The process is simple in principle but difficult in practice – as steel is heated, a thin layer of oxides forms on the surface, enough to differentially refract the light and cause a color change. The higher the heat, the thicker the layer, and the bluer the color. [Chris] uses a custom-built tray filled with brass shavings to even out the heat of a propane torch, but even then it took several tries to get the color just right. As a bonus, [Chris] gives us a primer on heat-treating the steel hands – the boric acid and methylated spirits bath, propane torch flame job and oil bath quenching all seems like something out of a wizard’s workshop.

We’ve covered [Chris]’ build before, and we encourage everyone to tune in and watch what it means to be a craftsman. We only hope that when he finally finishes this clock he starts another project right away.

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Gitaar van Schroot – The Scrap Metal Guitar

Sheet metal. Beer cans. Pieces of chain. Not items you’ll typically find on the BOM for a custom guitar. But nobody told [Maarten van Halderen] that, and so he threw them all together into a gitaar van schroot, or scrap guitar for the Dutch impaired (YouTube link).

The video shows the build process, starting with plasma cutting and welding sheet steel for the body. The neck is fabricated from rectangular steel tube, with nails serving as frets. Overall it looks like a Les Paul, except for the sink strainer basket mounted in the sound hole and the crushed beer and soda cans tacked to the body for decoration. The chains are a nice touch too. And this doesn’t appear to be [Maarten]’s first attempt at scrapyard lutherie  – toward the end of the video we see that the beer can axe joins a very steam-punk looking older brother. They’re both good-looking builds, and the video after the break proves they can sound pretty good too.

For a more classical take on the building of string instruments, check out this post on mandolins and violas. Or maybe you can just 3D print your next guitar?

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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”

Retrotechtacular: The Bessemer Converter

Here’s a rose-colored look into the steelworks at Workington, Cumbria in northern England. At the time of filming in 1974, this plant had been manufacturing steel nonstop for 102 years using the Bessemer process. [Sir Henry Bessemer]’s method for turning pig iron into steel was a great boon to industry because it made production faster and more cost-effective.

hot ingotsMore importantly, [Bessemer]’s process resulted in steel that was ten times stronger than that made with the crucible-steel method. Basically, oxygen is blown through molten iron to burn out the impurities. The silicon and manganese burn first, adding more heat on top of what the oxygen brings. As the temperature rises to 1600°C, the converter gently rocks back and forth. From its mouth come showers of sparks and a flame that burns with an “eye-searing intensity”. Once the blow stage is complete, the steel is poured into ingot molds. The average ingot weighs four tons, although the largest mold holds six tons. The ingots are kept warm until they are made into rail.

The foreman explains that Workington Works would soon be switching over to a more modern process. As it was, Workington ran a pair of Bessemer converters on a 40-minute schedule, ensuring constant steel production from ore to rail. Between 1872 and 1974, these converters created an estimated 25 million metric tons of steel.

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Behold Lil’ Screwy, A Homebrew 100-Ton Press

Here we have a magnificent example of the power of the inclined plane. [Chris] has built Lil’ Screwy, a 100-ton home-built press for about $35 plus scrap on hand. He demonstrates its frightening power by punching a 17-mm hole through 8mm-thick steel using an Allen key.

As [Chris] explains in his hilarious video waiting for you after the jump, the force comes from using really big screws. Lil’ Screwy uses four 1-inch L7-rated ready rods with eight threads to the inch. The bolts run between two 1″ steel plates to form the press. In the top plate, he drilled 1″ holes. The bottom holes are drilled out 7/8″ and tapped so the two plates clamp together with awesome crushing power when you twist the giant coupling nuts.

[Chris] milled a pocket in the underside of the top plate for a big neodymium magnet that will keep, for instance, a 17-mm Allen key in place while you punch a piece of steel with it. He has a ring of smaller ones embedded into the bottom plate to hold supports in place for broaching.

As a special bonus, [Chris] shows you how to stick it to the man when it comes to using that last bit of Never-Seez in the can, and also how to make your decals temporarily repositionable.

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Retrotechtacular: How a Bicycle Is Made

Does your bicycle master boardwalk and quagmire with aplomb? If it was built by the Raleigh Bicycle Company, it ought to. This week’s Retrotechtacular is a 1945-era look into the start-to-finish production of a standard bicycle. At the time of filming, Raleigh had already been producing bicycles for nearly 60 years.

The film centers on a boy and his father discussing the purchase of a bicycle in the drawing office of the plant where a bicycle begins its life. The penny-farthing gets a brief mention so that the modern “safety model”—wherein the rider sits balanced between two wheels of equal size—can be compared. The pair are speaking with the chief designer about the model and the father inquires as to their manufacturing process.

We are given the complete story from frame to forks and from hubs to handlebars. The frame is forged from high-quality steel whose mettle is tested both with heat and with a strain much greater than it will receive in manufacture or use. It is formed from long pieces that are rolled into tubes, flame sealed at the joint, and cut to length. The frame pieces are connected with brackets, which are formed from a single piece of steel. This process is particularly interesting.

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