For home metallurgy, there are two sources of information for the heat treatment and tempering of steel. The first source is academic publications that include theoretical information, while the second includes the home-spun wisdom of blacksmiths who learn through trial and error. [Ben Krasnow] put up a great video that tries to bridge that gap with some great background information with empirical observations to back up his claims.
For investigating the hardness of steel, a few definitions are in order. The first is stiffness, or the ability of a material to ‘spring back’ after being flexed. The second is strength, specifically yield strength, which is the amount of strain a material can withstand before being permanently deformed.
[Ben] did all these experiments with a 1/8″ W1 steel drill rod. As it came from McMaster, this rod could handle a bit of force before becoming permanently bent, and in terms of stiffness was much better than a piece of coat hanger wire [Ben] had lying around. After taking a piece of this drill rod, heating it up to a cherry red and quenching it in water, [Ben] successfully heat treated this steel to a full hardness. After putting it on his testing jig, this full hardness steel didn’t deform at all, it simply broke.
Full hardness steel is basically useless as a structural material, so [Ben] tried his hand at tempering pieces of his drill rod. By putting a few pieces in a kiln at the requisite temperature, [Ben] was able to temper his drill rods to be stronger than the stock material, but not as terribly brittle as a full hard rod.
Continue reading “[Ben Krasnow] Discusses the Heat Treatment of Steel”
The illutron hackerspace in Copenhagen makes their home on a barge sitting in port. Not only is this awesome, but the members of the hackerspace also worry about corrosion to their beloved fablab. In an effort to ally some fears about rust slowly eating through the hull, [Dzl] has rigged up a cathodic protection system for their hull, essentially preserving their barge at the expense of a few old steel rails.
Cathodic protection systems are able to protect the steel of a ship’s hull by offering up a sacrificial anode made of aluminum or zinc. This can be done by either attaching a sacrificial anode directly to the hull, or with a more complex system that connects both the cathode (the ship) and the anode (an engine block) to a DC power source.
[Dzl] is converting mains voltage down to 12 VDC, then further lowering the voltage with an Arduino-controlled buck converter. The control panel allows for adjustments in the voltage, as well as a nice uptime meter to make sure it’s running.
The results are fairly impressive; in the above pic, the right piece of steel was electrically connected to the barge’s hull, while the left piece was free to rust in the North Sea. That’s only two days worth of corrosion there.
You can find galvanized steel pipes at Home Depots and construction sites all around the world. These relatively thin-walled steel pipes would make for great structural members if it weren’t for the fact they were covered in a protective layer of zinc. This layer of galvanization lends itself to crappy welds and some terrible fumes, but badass, TV personality, and hacker extraordinaire [Hackett] shows us how to strip the galvanization off these pipes with chemicals available at any hardware store.
Since the galvanization on these pipes covers the inside and the outside, grinding the small layer of zinc off these pipes is difficult at best. To be sure he gets all the zinc off this pipe, [Hackett] decided to chemically strip the pipes with a cup full of muriatic acid.
The process is simple enough – fill a cup with acid, dunk the ends of the pipes, and clean everything up with baking soda. A great way to turn scrap pipe into a usable material, make a cool paper mache volcano, and avoid ‘ol galvie flu
Continue reading “On not getting metal fume fever with galvanized conduit”
The last few years have seen a lot of dangerous storms rip through middle section of the United States. We’re surprised to hear that many residents in that part of the country don’t have basements to take refuge in when in imminent danger. But a resourceful hacker will always be able to find a way to improve their own situation. This example is particularly useful. It’s a steel storm shelter which opens into the garage.
It all starts with a cage made of square tube. With the skeleton fully assembled it is wrapped in steel plate, adding weld joints running nearly the entire length of each of the cage’s ribs. The image at the left shows the steel door frame clamped in position. Check out the finished version on the right after the shelter has been slid into place and bolted to the concrete slab.
The Reddit discussion includes a debate on whether the door should swing in or out. Swinging out means you could be trapped if the opening is blocked by debris. But there may be scientific research that proves this is a better orientation. Either way, we hope the three dead bolts, door latch, and heavy-duty hinges will stand up to the pressure if this is ever used.
[Sir Keyboard Commando] just emerged from his machine shop to show off the 1/6th scale model of a Civil War mortar which he recently finished fabricating. It started with some bar stock that measured four inches in diameter and accepts steel balls the size of golf balls as ammunition.
The bore diameter is 1.725″ which gives just a bit of clearance for the 1.685″ golf ball specs. Each of the steel balls weighs in at just over 11 ounces. You get a really good look at the finished mortar in this test-fire video. It’s quite small but [Sir Keyboard Commando] reports that the full assembled unit still weighs in at a whopping forty pounds.
This certainly isn’t an improvised weapon, but we’re quite surprised to see it being test fired. We’d bet it turns some heads that the local firing range.
Here is something we didn’t expect (NSFW). The machinima crew behind RedVsBlue, Rooster Teeth, actually did a hack!
The idea is simple enough, how could you experience driving a vehicle like in a video game – aka, third-person. With some steel bar, Canon 5D camera, and a 15inch monitor inside of a blacked out cab, they accomplished just that.
What surprised us the most, is the great difficulty and difference there is between the video game vehicle and the real life one. But all of us here at HAD know why; they need to replace the steering wheel with a joystick. While they’re at it they can make it wireless and remote-controlled. Finally a HUD would be easy enough to program (might we suggest processing). Oh dear lord, is the world ready for this!?
We asked for CNC projects, and wow did you guys deliver!
First up is [J-J Shortcut’s] MDF based CNC. He’s made three thus far, with the most recent costing about 180 euro and taking 2 months to build.
[Qwindelzorf] has also constructed a multitude of CNC machines including this industrial size router and this smaller miller.
Finally, [Mick’s] large steel CNC which just made its first cut only a week ago!
Keep up the great work guys, CNC machines are not easy to build and your accomplishments are ones for the record books.