Spiral Stairs Pita Bread Exhaust Headers Molded Limestone Artwork
spiral stairs were part of a strategy to defend the towers of medieval castles. Attackers had to climb single-file and couldn't storm the castle all at once. And at the top of the stairs, the guardsmen could more easily maneuver their swords, giving them the upper hand. Spiral stairs take people to the next level without taking up a lot of space. They're compact, and with their corkscrew curvature, they can also be architectural features. Production starts with the steel hubs cut to the desired riser height. A worker files the sharp edges smooth and drills a threaded hole which will be used to fasten the treads in place. A computer-driven plasma system cuts through a sheet of steel to produce the pie-shaped stair treads. A worker nestles a tread to the hub and clamps them in a weld fixture. He also clamps structural supports to the base of the tread. With everything in the right configuration, he welds the supports to the tread and the hub. He'll make 12 of these hub and tread assemblies. He chips off the weld slag for cleaner seams. A team slides the hub and tread assemblies on to the center pole and rotates them to the correct position. The design geometry dictates the rotation. Once rotated correctly, the workers fasten the hubs to the pole and add a platform for the top step. A baluster spins in a lathe, as tools cut it to length and round the end to the correct diameter. The operator measures the diameter. He inserts the rounded end in a dye that carves the thread into it. A worker welds a steel cup just above the threaded part of the baluster. This cup will support the baluster once it's been installed on the thread. He grinds the weld scale from the cup. He inserts the baluster through holes in a metal spacer in the tread. He screws a nut on to the end to secure it. Using rollers now, another worker twists long strips of metal into spiraling hand rails that match the rise of the stairs. He fits the rail to the top balusters and clamps it in place. He then welds the balusters to the rail. He adds more railing until it spirals all the way down to the first step. The team secures it to the platform. The spiral staircase's metal structure is now complete. It's ready for the wooden accents. A worker applies glue to pieces of red oak. He'll use two of them to make one stair tread. He clamps two tread sets in a fixture while the glue sets. He inserts a shim and tightens the clamp to apply downward pressure. Once the glue has cured, a planer shaves the tread perfectly flat and to the desired thickness. After refining the profile, a worker rounds the edge of the stair tread using a router. After gluing strips of wood together to create a curved railing, he sands the excess adhesive, and with a file, removes more of the glue. He turns the railing over and carves a groove in the wood. This will enable the railing to be installed over the metal rail support. He adds some detailing along the edge. A team then fits the wooden railing to the metal support structure. All of the rail sections fit together perfectly. After the pre-fit, they remove the railing and sculpt the edges to be rounder. The rounded edges complement the overall spiral design. A worker pre-fits the wooden treads to the metal structure and then disassembles the entire spiral staircase for painting and staining. The spiral stairs are then ready for reassembly in the building they were designed for. They'll definitely add a certain twist to the interior design. Originating in the middle east, pita bread has been around for thousands of years. Today, its popularity continues to grow around the globe. Part of its appeal is its versatility. People can stuff their pita's pockets, use it as a sandwich wrap, or slice it for dipping. Pita bread may be flat, but that doesn't mean it's boring. Anyone can use pita to make any number of interesting lunchtime combinations. Making pita bread starts with silos full of flour. A blower system delivers the flour to an automated sifter. The sifter shakes the flour through three levels of mesh to filter out impurities. Magnets extract any metal contaminants. Workers prepare a pre-mix of sugar, salt, yeast, and preservatives. They combine these ingredients with the sifted flour in a big mixer and add water. The mixer is equipped with numerous bars that rotate horizontally to blend the ingredients. The operator opens the mixer and spins it one more time to eject the dough into a bin. He rolls the bin to the next station. Here the pita dough goes into a hopper. And from there, it drops into a machine called a dough divider. This machine turns big chunks of dough into many small blobs. To do this, it forces the dough through a round hole, and a guillotine blade chops it to the correct thickness. The dough blobs ride a conveyor and pass under a roller that flattens them. Flour from an overhead sifter dusts the dough blobs to keep them from sticking to the machinery. Each one of these flattened dough blobs will eventually become a pita. The round pieces of dough now ride a conveyor up to a warm zone. Over a period of 15 minutes, the yeast ferments, causing the dough to rise. Out of the fermentation station, a roller flattens the pita dough segments again. They're now ready to be rolled very thin in a process known as sheeting. The next roller presses the pita dough much thinner. Rolling it in one direction makes the dough segments oval-shaped. The oval pitas ride by a pusher that now shoves them towards the final roller. It rolls the dough in the other direction to round out the shape and make it even thinner. Perfectly round and thin, the pitas now travel up to another fermentation operation. Inside, the temperature is toasty. It's warm enough to reawaken the yeast and cause the dough to rise again. Conveyors move in criss-cross directions to take the pitas back and forth. This zig-zagging journey lasts about 15 minutes. When the pitas emerge from the chamber, they have thickened up substantially. They head into an oven where the magic happens. The oven's temperature is between 750 and 930 degrees fahrenheit. They spend just 15 seconds in it. This flash-baking causes the water in the dough to turn to steam. The steam puffs the pitas, creating pockets inside. The pitas then travel on conveyors for a 20 minute cool down. As they cool, they deflate. The process has created pockets in the pitas. Once sliced open, the pockets can be stuffed to create sandwiches. Workers stack the pitas six high for packaging. The next conveyor delivers the stacks into the clutch of an automated arm. Just ahead, a burst of air opens a bag and the arm inserts the pitas into it. At the same time, it pushes the bag on to the next conveyor. Moving forward, another device automatically twists the open end of the bag. The device applies a plastic lock tab to the twisted end of the bag, sealing the pita breads inside. The bags pass by a metal detector, and then they're on their way to the supermarket. This pita bread has taken 45 minutes to make and package, but it should enable lunch to come together very quickly. Installing exhaust headers will add extra power from a car's engine. They bolt on to the engine, giving each cylinder its own exhaust pipe leading to the collector, which connects to the car's main exhaust pipe. That's more efficient than having all the cylinders exhaust into a common manifold. A header draws out significantly more spent exhaust gasses after combustion, leaving room for a greater amount of new gas and fresh air to enter the cylinder for the next combustion cycle. Headers are made of steel or stainless steel. A worker uses a roll cutter to slice tubes into nearly 6-inch-long pieces for the header's collector. A forming tool on a press stretches one side of the collector outward. Then the worker places the same side on an end-forming machine, which shapes it like a four-leaf clover. He slips a flange over the unshaped side and widens that side to create the ball portion of the gasketless ball and socket connection to the car's main exhaust pipe. Meanwhile, another worker roll cuts narrower tubes into 32-inch-long pieces to make the header's primary tubes, the ones that attach at the top to engine's cylinders. A worker slides a tube on to a mandrel, then the computer-guided mandrel bender bends the tube in four places. The mandrel fills the inside of the tube just up to the bend point, preventing the tube from compressing or collapsing under pressure. The header they're making here is for a four-cylinder engine, so it has four primary tubes. An eight-cylinder engine requires a pair of headers, whereas a six-cylinder engine requires a pair of three-tube headers. A worker trims the bent primary tubes to the required length with a bandsaw. The sawed edges of the tube are ragged, so the next step is to grind them smooth. After grinding, the edge no longer looks like this. Workers heat the top end of the tube with a torch to soften the steel. They place the end into an end-forming machine. The machine shapes the end to match the top profile of the cylinder, to which the tube will be mounted. Cylinder profiles vary from engine to engine, so workers simply change the forming tool on the machine. A worker clamps the header flange with its four exhaust ports on to an assembly jig and positions the top end of a primary tube in each port. He inserts the bottom ends into the four-leaf-clover-shaped collector. He then welds the top end of each tube to its exhaust port on the header flange. Then he welds a tag with the company name on to one of the tubes. Finally, he welds the bottom end of the tubes to the collector. The header's three sections--  flange, tubes, and collector-- are now fused. The worker grinds down the weld around the ports until it's nearly flush. The remaining bit of weld material encircling the port will act as a seal to prevent leakage. During the welding, some welding material drips into the header flange's openings, so a worker reams the bolt holes with a drill and grinds the edges of each port. He mounts the header on the corresponding engine's cylinder head to make sure bolt holes are sufficiently cleared. Then he runs a torch over all the joints to check the welds. The flame would shoot through any hole in a weld, alerting them to repair it. This factory applies one of two finishes on its exhaust headers. The basic one is a coat of black water-based paint sprayed on and air-dried. It prevents surface rust from forming while the part is warehoused. The higher-end finish is an aerospace-grade ceramic coating, available in black or silver. This baked-on finish protects the headers from rust for many years of high-performance driving. This may look like ivory, but it's actually limestone. It looks as though it's a sculpted work of art, but it's actually molded. How does one mold limestone? 200 years ago, some people in france figured out how, and their descendents are still molding limestone artwork today. This unique art form exists because, two centuries ago, a family in france discovered springs amid volcanic rock, springs with water so rich in calcium carbonate that it petrified into stone. That is limestone. The family carved out caves, then invented a way to capture the calcium carbonate and mold sculptures with it. The descendents of the family continue that tradition today. The springwater contains two grams of calcium carbonate per liter and a lot of iron oxide, which makes the water orange. The original troughs direct the water on to a bed of wood shavings. The shavings trap the iron oxide, and the calcium carbonate floats to the surface. In the workshop, the owner of the company-- the seventh generation of the founding family-- makes the mold. He heats something called gutta-percha in a pot of water to soften it up. Gutta-percha is a natural latex made from the sap of the gutta tree. Once it's soft, he weighs out the required amount using the workshop's original scale. Then he kneads it to force out trapped air and make it more malleable. After forming it into a ball, he places it in an old press made my his great-grandfather. The press shapes the gutta-percha into a rectangle measuring 7-by-10 inches. After cooling in the press for 30 minutes, the gutta-percha has hardened just enough to maintain the rectangular shape. He removes it from the press and places a silicone-designed template on top. He cuts the gutta-percha to the shape of the template. He places the gutta-percha on top of a pattern created by an artist. He places the template on the gutta-percha, then a plank of wood on top of that. He puts the entire assembly under an old screw press. An hour later, he removes the assembly from the press and gently separates the layers. The artwork design is now transferred from the pattern to the gutta-percha. He sets it aside to cool to a hard state. When the work of art is either too wide or high to fit into the traditional screw press, the artisan then sculpts the pattern out of clay. Once the clay hardens, he coats it in silicone to make the mold. This modern mold-making technique is a bit trickier because silicone can't be reheated and reworked like gutta-percha. The silicone takes about 24 hours to harden into a flexible mold. A silicone mold can be used only once. And because it's so flexible, it has to sit on a support tray so that it doesn't buckle when filled or moved. Now it's time to mold the limestone. A craftsman positions the molds under these liquid limestone waterfalls. The carbonic gas in the liquid gradually evaporates, leaving accumulating deposits of calcium carbonate in the molds. An artisan moves every mold to a new position daily so that the dripping water hits all parts of it. Artwork just one 1/5 of an inch thick requires six months under the fountain. Artwork 4/5 of an inch thick requires two years. To extract the limestone artwork from a traditional mold, the artisan immerses it in hot water to soften the gutta-percha so that he can gently peel it off. Every intricate detail of the design in the gutta-percha is now replicated in limestone. This molded rock is as strong and hard as marble. To extra the artwork from a silicone mold, an artisan removes the support tray and lifts off the silicone. The company has more than 500 artwork patterns in stock dating back to 1821. Not all the molded limestone looks the same. The artisans can tailor the shade from white to ivory by controlling how much iron oxide they remove from the water.