A small disk sander is a useful and cheap addition to the shop. For about $100, you can buy a cheap combination 6″ disk/belt sander that’s extremely useful. The size and cost of power tools does not scale linearly, and if you want a big disk sander you might as well make your own.
The motor for this build is a 1kW single phase motor pulled from a floor polisher found in the trash. That’s enough to push a sanding disk around, but when you get to tools this large, you need a good base, good tilt mechanism, and everything should be extremely heavy.
This build meets all those requirements while still using mostly recycled components. The work table is actually made of three pieces of recycled aluminum epoxied together. Yes, you should cringe at this, but it actually makes a little bit of sense: thinner pieces can be cut on a table saw, and if you’re extremely careful during the glue-up, you can cut the mitre slot without a mill. This frame attaches to a frame made from aluminum extrusion and filled with a homebrew epoxy granite mix. Remember, heavy is better here.
In keeping with making a huge disk sander out of stuff pulled out of the trash, the trunnions and motor hub were cast out of aluminum melted in an old propane tank furnace. Once these were cleaned up, a disk was mounted on the hub and trued up in the most unsafe manner possible.
With a few additions including a machined mitre gauge, dust collector, and legs made out of wood that’s far too pretty for a simple shop tool, this huge assemblage of trash turned out to be a great sander. You can see a few videos of it below.
Continue reading “Building A 20 Inch Disk Sander”
Nintendo is well known for… odd… hardware integration, but this video takes it to a new level. It’s a Gamecube playing Zelda: Four Swords Adventure, a game that can use a Game Boy Advance as a controller. [fibbef] is taking it further by using the Gamecube Game Boy Advance player to play the game, and using another GBA to control the second Gamecube. There’s also a GBA TV tuner, making this entire setup a Gamecube game played across two Gamecubes, controlled with a Game Boy Advance and displayed on a GBA with a TV tuner. The mind reels.
TI just released a great resource for analog design. It’s the Analog Engineer’s Pocket Reference, free for download, if you can navigate TI’s site. There are print copies of this book – I picked one up at Electronica – and it’s a great benchtop reference.
A few months ago, a life-size elephant (baby elephants are pretty small…) was 3D printed at the Amsterdam airport. A model of the elephant was broken up into columns about two meters tall. How did they print something two meters tall? With this add-on for a Ultimaker. It flips an Ultimaker upside down, giving the printer unlimited build height. The guy behind this – [Joris van Tubergen] – is crazy creative.
And you thought TV was bad now. Here’s the pitch: take a show like Storage Wars or American Pickers – you know, the shows that have people go around, lowball collectors, and sell stuff on the Internet – and put a “Tech” spin on it. This is happening. That’s a post from a casting producer on the classic cmp message boards. Here’s the vintage computer forums reaction. To refresh your memory, this is what happens when you get ‘tech’ on Storage Wars. Other examples from Storage Wars that include vastly overpriced video terminals cannot be found on YouTube. Here’s a reminder: just because it’s listed on eBay for $1000 doesn’t mean it’ll sell on eBay for $1000.
You saw [Chris] cast aluminium on the cheap using Kinetic Sand a few weeks ago, didn’t you? He recently got his meaty hands on some titanium through the magic of modern transactional methods and was bowled over by its strength, hardness, and poor heat transfer.
He thought he would cast it into a nice, strong bottle opener. As you can probably guess, that didn’t go so well. First off, it wasn’t easy to saw through the thin rod. Once he did get it split in twain, it was surprisingly cool to the touch except at the tip. This is nasty foreshadowing, no?
[Chris] takes a moment to help us absorb the gravity of what he’s about to do, which of course is to send several hundred amps through that poor rod using a DC arc welder. Special precautions are necessary due to the reaction between oxygen and heated titanium. His trusty graphite crucible is grounded to the bottom of a big aluminium tub, and a cozy blanket of argon from a TIG welder will shield the titanium from burnination.
Well . . . the titanium didn’t melt. Furthermore, the crucible is toast. On the up side, vise-enabled cross-sectional examination of the crucible proved that there was still gold in them there walls.
Do you have any (constructive, on-topic) suggestions for [Chris]? Let him know below.
Continue reading “Fail of the Week: This Inanimate Titanium Rod”
[Julia and Mason] have been perfecting their microwave-based lost PLA casting technique over at Hackaday.io. As the name implies, lost PLA is similar to lost wax casting techniques. We’ve covered lost PLA before, but it always involved forges. [Julia and Mason] have moved the entire process over to a pair of microwaves.
Building on the work of the FOSScar project, the pair needed a way to burn the PLA out of a mold with a microwave. The trick is to use a susceptor. Susceptors convert the microwave’s RF energy into thermal energy exactly where it is needed. If you’ve ever nuked a hot pocket, the crisping sleeve is lined with susceptor material. After trying several materials, [Julia and Mason] settled on a mixture of silicon carbide, sugar, water, and alcohol for their susceptor.
The actual technique is pretty simple. A part printed in PLA is coated with susceptor. The part is then placed in a mold made of plaster of paris and perlite. The entire mold is cooked in an unmodified household microwave to burn out the PLA.
A second microwave with a top emitter is used to melt down aluminum, which is then poured into the prepared mold. When the metal cools, the mold is broken away to reveal a part ready to be machined.
We think this is a heck of a lot of work for a single part. Sometimes you really need a metal piece, though. Until metal 3D printing becomes cheap enough for everyone to do at home, this will work pretty well.
That kinetic sand stuff is pretty cool. It’s soft, it builds motor skills, and outside of sprinkling it on carpet, it’s not messy. If you don’t know, it’s 98% sand and 2% polydimethylsiloxane, which is a major component of Silly Putty, and according to a certain yellow and red clown, it’s safe enough to put in chicken nuggets. [Chris]’s wife bought him some, probably because she wanted to see him play around with something that isn’t potentially deadly for a change. In the course of researching its magical properties, he found out that it doesn’t really have a thermal breakdown point, per se. At high enough temperatures, It vitrifies like a sand castle in a mushroom cloud. Between this property and its malleability, [Chris] thought he’d have a reasonable substitute for founding sand. As you can see in his latest experiment, he was right. As a bonus, he managed to turn the benign into the dangerous.
[Chris] had never cast aluminium before, so he decided to start small by making an offset cam for a rotary broach. He packed some magic sand in a wax paper cup and shoved the cam in to make the negative. Then he cut down some aluminium rod and put it in a graphite crucible. He stuck his DC arc welder’s electrode down into the crucible and cranked it up to 50A. That wasn’t enough, so he went to 110. The crucible was soon glowing orange. He carefully poured the molten aluminium into the mold. Make the jump to see how it panned out.
Spoiler alert: there’s no cussin’ this time!
Continue reading “And So Castings Made of (Kinetic) Sand . . . Turn Out Pretty Well, Actually”
We usually shy away from calling things ‘magic’ in our features because, you know… science. But in the case of this Chevrolet manufacturing reel from 1936 the presentation is nothing short of an industrialized version of The Sorcerer’s Apprentice. Well, not in the sense of mischief, but in that there is almost no explanation and the way the footage is laced together you get the strong feeling that, at the time, this type of industrialization was magic; a modern marvel. The techniques and skills of each worked passed down from a master to an apprentice but virtually unknown to the general public.
The clip, which is also embedded below, starts off in the machine shop where mold makers are getting ready to go into assembly line production. From there it’s off to the foundry for part casting and then into the stamping plant where white-hot (perhaps red-hot, but black and white film) metal is shaped by man-mangling presses. The image above follows the cast, stamped, and machined parts onto the assembly line. We like seeing a room full of pistons being QA checked by hand using a width gauge and micrometer. The film continues through to the finished vehicle and we think you’ll agree there’s more than enough voyeuristic video here to overcome that lack of narration.
Continue reading “Retrotechtacular: The Magic of Making Cars in the ’30s”
Most of the robotics projects we see around here are heavy, metallic machines that move with exacting precision with steppers, servos, motors, and electronics. [Matthew] is another breed of roboticist, and created a quadruped robot with no hard moving parts.
[Matthew] calls his creation the Glaucus, after the blue sea slug Glaucus atlanticus. Inside this silicone rubber blob are a series of voids, allowing compressed air to expand the legs, gently inching Glaucus across a table under manual or automatic control.
Even though no one seems to do it, making a few molds for casting on a 3D printer is actually pretty easy. [Matthew] is taking this technique to an extreme, though: First, a mold for the interior pressure bladders are printed, then a positive of this print made in silicone rubber. These silicone molds – four of them, for the left, right, top and bottom – are then filled with wax, and the wax parts reassembled inside the final ‘body’ mold. It’s an amazing amount of work to make just one of these soft robots, but once the molds and masters are made, [Matthew] can pop out a soft robot every few hours or so.
There’s a lot more info on Glaucus over on the official site for the build, and a somewhat simpler ‘compressed air and silicone rubber’ tentacle [Matthew] built showing off the mechanics. Video below.
Continue reading “Soft Robotics, Silicone Rubber, And Amazing Castings”