Automatic Transmissions Silver Miniatures Hot Air Balloon Baskets Darts
Today on how it's made... Automatic transmissions... Silver miniatures... Hot-air-balloon baskets... And darts. Your car's all-important transmission is a system of gears and levers that transfers power from the engine to the wheels. With a manual transmission, you have to shift the gears yourself, but with an automatic transmission, the car's computer determines when it's time to shift and sends an electronic signal to activate or deactivate the appropriate gear. The transmission allows the engine to operate in its most efficient range, or powerband. It's assembled inside an aluminum housing called the transmission case. At the heart of the transmission are three sets of planetary gears, so named because there are smaller gears rotating around a larger central gear. The first gearset is called the final drive. It harmonizes the engine speed and driving speed. The final drive is attached to the differential, a component that lets the wheels move at different speeds so the car can turn. Workers install the steel parts connected to the shift lever, which puts the car into drive, reverse, or park. First, the manual detent lever. Then, the forward clutch support. The piece protruding from it is called the park paw. The actuator rod connects the detent lever to the park paw. It locks a gear that immobilizes the car when you shift into park. Now for the transmission's five clutches. Depending on what the transmission needs to do, clutches either let gearsets rotate or lock them in place. This clutch is called the forward clutch. By moving the input gearset and the reaction gearset, it enables the car to go forward when you shift into drive. Two clutches installed as one unit go in next. The coast clutch allows the car to coast in low gear and to brake progressively in higher gears when you take your foot off the gas. The second clutch is called the direct clutch. It locks the two gearsets so there's no reduction in speed. Next, the reverse clutch. It moves the reaction gearset so the car can back up. A clutch is made up of layers of metal and friction material, such as resin-impregnated paper. The transmission's second clutch uses both the input and reaction gearsets to switch the transmission into second, third, and fourth gears. With all the gearsets and clutches now in place, workers can connect the transmission to the rest of the car's electronics. These cables are known as the harness. Next come the drive chain and two sprockets. This hookup is the critical link between the transmission's gearsets and its torque converter. The torque converter is the component that transfers power from the engine to the transmission. The sprockets in the final drive convert the engine speed to the appropriate transmission gear. The car's computer directs this hydraulic control system to change gears as needed. The computer triggers an electronic switch called a solenoid to open a specific control valve. This applies hydraulic pressure, which engages the clutch around the relevant planetary gears. When the hydraulic pressure is released, it disengages the clutch and locks the gears. Now the final connection for the shifting mechanism, linking this manual valve to the detent lever. The shift lever moves the detent lever, which makes the valve direct hydraulic pressure accordingly. This steel bar, called the output shaft, directs transmission power from the final drive at one end of the transmission to the driver's side front wheel at the other end. Next, workers install springs and servos, part of the hydraulic control system that helps engage and disengage the clutches smoothly. This tube assembly goes in next. The control valves route hydraulic fluid through these tubes to the different clutches. Now the torque converter. It spins a shaft that turns the sprockets and drive chain that we saw earlier. A steel bar called a stub shaft is the final link, sending transmission power from the final drive and differential to the front wheel on the passenger side. Up next, making silver masterpieces on a miniature scale. Collecting and displaying miniatures isn't just child's play. It's become a serious hobby for grown-ups, who even buy fine silver in miniature. Avid collectors spare no expense because, after all, it's the little details that make the difference. In the world of miniatures, there's no need to downsize one's expectations. Here, you can find all the little luxuries. This silverware is no cheap reproduction. It's a tiny version of the real thing. To make it, silversmiths use tools and techniques that have been handed down over generations. This is a workbench from the 18th century. Today, they use one that's nearly identical. To make a miniature mug, workers begin by dividing its measurements by 12 so that the finished product will have the same proportions as the original. Next, a strip of silver is rolled out to about 0.02 of an inch thick. Then, small, round disks are punched out. A blast from a torch softens them so they'll be easier to work with. A dunking in acid eats away any impurities and leaves a frosty finish. One of these disks is set on a lathe. As it spins, a series of tools begin to give the thimble-sized mug its shape. Any mistake is a big one when you're working in such tiny dimensions, so the silversmiths have to work with great care. During the machining process, the frosty finish left by the acid is removed. The mug is buffed to add luster to its finish. And now it's time to make the mug's base. It's tapered to make a perfect fit. Small fragments of silver solder are placed between the two pieces. Then, the parts are heated to almost 1,500 degrees to fuse them together. Next, leftover silver pieces are cut up, and the scraps go into a crucible. A pinch of borax is added. This mineral will prevent unwanted oxides from forming as the scraps are melted down. Silver is far too precious, so workers don't want to waste even a single scrap. The molten silver is poured into a plaster mold. Then the mold is plunged into cold water. The temperature change causes the plaster to explode, exposing three tiny silver handles. One of the handles is soldered onto the little silver mug. And now all the pieces of the miniature are in place. Next, the miniatures are placed in a bucket of steel shot and soapy water. The friction cleans and polishes them. The soapy water is strained out, and the gleaming miniatures are revealed. Each silver miniature has to meet the same purity standards as full-sized silver pieces. In this factory in britain, the regulations have been around for 700 years. The maker's mark, called the hallmark, is the stamp of authenticity. Hallmarking a miniature can be a bit awkward, and some articles are just too tiny to mark. When it comes to replicating silverware, it seems no job is too small, and there are plenty of shining examples in the world of miniatures. When we return, behind the scenes at a hot-air-balloon factory. Did you know that some hot-air-balloon baskets are more than 20 feet long and can carry more than 30 people? This pioneering form of human flight was invented in france in the late 1700s, and ever since then, passengers have been taking to the skies for an unforgettable ride and an awesome view. It all starts with a little high-tech basket weaving. First, the frame is constructed. Workers cut pieces of stainless-steel tubing. They manually round the corner pieces, then weld all the parts together. A sheet of plywood is cut for the floor. Then holes are drilled into it for stainless-steel support cables. These cables will reinforce the floor against the passengers' weight. After marking off the area that the basket walls will occupy, workers run the cables under the floor, which is lying upside down, leaving extra cable on both ends to come up the sides of the basket. Then they notch a groove that is the width of the cables and runners. Runners are length of ash wood that protect the base of the basket and give it rigidity. After bolting the runners down, workers use a branding iron to burn the company logo into the floor. A spray coat of lacquer will prevent moisture from rotting the wood. Larger baskets need diagonal reinforcement cables for extra support. The basket walls are made of cane-- the stiff stems of a tropical asian plant. The cane soaks overnight in a water tank. By morning, it's supple, and the weavers can begin their craft. They start by installing uprights, attaching each one to the frame at the top and bottom with a thin piece of cane. Then they feed the support cables from the floor up through the frame. The uprights are 18 inches apart along the sides and 4 inches apart around the corners. The weavers fill the gaps with thinner uprights every two inches. The uprights are tied to the frame and floor with rope. Once they're installed, it's time to build the basket walls from the bottom up by interlacing horizontal canes. A pair of weavers can finish a small basket in a day. Large baskets can require a 4-person team and take up to three weeks to complete. Weavers use two techniques-- randing, going in and out with one cane, and waling, weaving three canes at once. Waling makes a more solid basket but one that's significantly heavier, because it uses triple the amount of cane. Some models have stainless-steel steps woven into the basket. These give passengers a better foothold when climbing in. The weaving ends just below the top of the frame. Weavers finish off the job by splitting the remainder of each upright down the center with a utility knife, then flattening and wrapping what's left around the frame. The weavers integrate rope handles at the top of the basket so passengers have something to hold on to during the ride. They also put handles at the bottom for carrying the basket. Now they pad the frame with foam, cutting holes to let the support cables through. The foam provides both comfort and safety, cushioning passengers from the hard metal during a bumpy ride. After taping the foam pieces together to prevent shifting, workers slip on a leather cover and lace it closed. Finally, with a few bangs of the hammer, workers expose the short tubing to which the load frame will connect. The load frame carries the burners high above the basket. A heating coil surrounds each burner. To make this piece, workers first wrap a stainless-steel tube around a form, then rivet on a reinforcement band. The basket carries lightweight fuel tanks containing cold liquid propane. The propane flows upward into the coil. When the pilot fires up a burner, the flame heats the coil, transforming the propane flowing inside from liquid to gas. The gas feeds the flame, which heats the air inside the balloon. Hot air is lighter than cool air, so the balloon literally rises to the occasion. Up next, the art of the dart. The game of darts dates back to the middle ages, when english soldiers looking for fun began pitching arrows at the bottom of an empty barrel. When winter came, the soldiers moved their game indoors, but they couldn't throw big arrows around inside, so they used shortened versions, and the game was on. Today's darts are finely crafted little missiles. Production begins with the flight shaft, the piece that the dart's wings are attached to. Workers load aluminum rods three yards long into a machine that has several cutting implements. This army of tools works on the aluminum rod from all angles... Shaping it into dozens of shafts. Threads are cut into the shaft's exterior, and one of its ends is hollowed out so it can be screwed onto the dart barrel later. A cross saw cuts slots into the other end for attaching the wings. Oil flushes away the shavings. It also keeps the tooling cool, so it stays sharp enough to cut through metal. The completed shafts fall into a bin to await further assembly. Next, brass rods are loaded into a similar machine. Its tooling carves the brass rod into barrels-- the main part of the dart that you grip. One end of the barrel is threaded and tapered so the shaft can be screwed onto it. This tapering also makes the dart aerodynamic. Next, tools with angled grooves cut ridges on the outside of the barrel to make the dart easier to grip. The process is called knurling. Another tool then cuts the brass barrel to the correct length. Some dart barrels are made from tungsten, which is quite dense, so the barrels can be slimmer. Slimmer darts can give you an advantage in tight scoring situations. That's why pros often prefer tungsten darts and have them custom made, even choosing their own knurling grip. These are knurling wheels-- another way to etch the grip pattern into the dart barrels. Knurling wheels come in an assortment of patterns, all designed to help you keep a firm hold until the dart takes flight. Now it's time for the darts to get their sharp points. A hydraulic press forces steel tips into the hollowed ends of the dart barrels. With the point now snugly in the barrel, the dart is ready for its wings. Dart wings are made from polyester film, which first winds through printing rollers. Some print jobs involve just one basic color while others layer many colors to build up a design. In the world of darts, the wings are known as flights. A machine cuts out the flight shapes, and they accumulate in big piles. Flights are made in various shapes. This is just one of them. Workers fold the cutouts together to make a flight. They check each one for symmetry, because an out-of-proportion flight could wreck a player's game. Now it's time to screw the shaft to the barrel of the dart. The polyester flight slides into cross slots on the end of the shaft. And now this set of darts is ready to take aim. It takes less than a minute to make a dart... But less than a second for this flying missile to find its mark.