How It's Made

Narrator: TODAY ON "HOW IT'S MADE"...

HORSESHOES...

...DISHWASHERS...

...GRAPHITE FLY RODS...

...AND FROZEN PIZZAS.

HORSES FIRST WORE LEATHER AND METAL SHOES AROUND 500 A.D.

TO PROTECT THEIR HOOVES FROM WEAR AND TEAR.

TODAY, DEPENDING ON THE ANIMAL'S VOCATION,

HORSESHOES ARE USUALLY MADE OF STEEL, ALUMINUM, OR PLASTIC.

A FARRIER IS SOMEONE WHO MAKES THE HORSESHOES

AND CAREFULLY APPLIES THEM.

A HORSE'S HOOF HAS A HARD OUTER WALL

LIKE A FINGERNAIL, ONLY MUCH THICKER.

THE FARRIER ATTACHES THE HORSESHOE TO THIS WALL

WITH HEAT AND LEAD NAILS.

THE HORSE FEELS NO PAIN

BECAUSE THE NAILS DON'T REACH THE SENSITIVE TISSUES INSIDE.

HORSES GET NEW SHOES ABOUT EVERY FIVE WEEKS.

AFTER REMOVING THE OLD ONES,

THE FARRIER USES A FILE TO TRIM THE WALL'S GROWTH

SINCE THE LAST CHANGE -- ABOUT 1/3 OF AN INCH.

HE MEASURES THE HOOF'S CONTOUR,

MARKS THE MEASUREMENT ON A STEEL BAR,

AND CUTS IT TO SIZE WITH A ROTARY SAW.

STEEL IS THE MATERIAL OF CHOICE

BECAUSE IT'S AFFORDABLE AND DURABLE.

NEXT, HE HEATS THE BAR UNTIL THE MIDDLE'S WHITE-HOT.

HE BRUSHES OFF ANY DIRT,

THEN DIPS THE BAR IN WATER TO COOL IT.

THEN HE HAMMERS THE ENDS

TO REDISTRIBUTE THE METAL TOWARD THE MIDDLE.

THIS WIDENS AND THICKENS THE PART OF THE HORSESHOE

THAT GETS THE MOST WEAR,

SINCE THE FRONT OF THE HOOF HITS THE GROUND FIRST AND HARDEST.

AFTER REHEATING THE BAR,

HE HAMMERS IT AGAIN, THIS TIME WITH NO COOLDOWN.

FOR LARGER SHOES,

TWO FARRIERS TAKE TURNS HAMMERING

SO THAT IT GOES FASTER, AND THEY CAN SHAPE THE STEEL

WHILE IT'S STILL HOT AND PLIABLE.

USING A DRAFTING COMPASS,

THE FARRIER GAUGES WHERE TWO GROOVES FOR NAILS WILL GO.

HE REHEATS THE BAR,

THEN HOLDS A SHARP-ENDED TOOL AGAINST IT,

WHILE ANOTHER FARRIER DRIVES IT IN WITH A HAMMER.

THE NAILS WON'T PROTRUDE WHEN THEY'RE EMBEDDED IN THE GROOVES.

THESE AREAS WILL ALSO FILL WITH DIRT TO GIVE THE HORSE TRACTION.

THE FARRIERS ROUND THE SHARP EDGES OF THE HORSESHOE

SO THE ANIMAL WON'T CUT ITSELF WHEN IT'S LYING DOWN.

THEY MAKE THE NAIL HOLES

BY FIRST DRIVING THIS TOOL INTO THE GROOVES.

THEN THEY USE ANOTHER TOOL TO PERFORATE THE STEEL,

HAMMERING IT INTO THE SHOE OVER AN OPENING IN THE ANVIL

THAT LETS THE TOOL PIERCE THROUGH.

THE FARRIER THEN REPEATS THESE STEPS ON THE OTHER SIDE.

IT TAKES 2 FARRIERS ABOUT 15 MINUTES

TO MAKE A PAIR OF HORSESHOES.

THE FIRST FARRIER HEATS ONE SHOE,

WHILE THE SECOND HAMMERS THE OTHER.

LIKE THE HOOVES,

THE FRONT AND BACK SHOES ARE DIFFERENTLY SHAPED.

THE FRONT PAIR ARE ROUNDER, THE BACK ONES, MORE OVAL,

BECAUSE THE HORSE'S HIND HOOVES HAVE EVOLVED

TO DIG INTO THE GROUND FOR TRACTION.

THE FARRIERS ALSO HAMMER PART OF BOTH CURVES,

FLATTENING THE EDGES INTO RAISED SIDES CALLED CLIPS.

THESE HELP THE SHOE FIT ONTO THE HOOF.

FOR LARGER WORKHORSES LIKE CLYDESDALES,

THE FARRIERS BEND THE ENDS DOWNWARD

TO GIVE THE FEET MORE TRACTION.

IT'S NOT UNCOMMON FOR A 2,000-POUND HORSE

TO HAVE TO PULL TWICE ITS WEIGHT.

NOW TIME FOR THE FITTING.

AFTER HEATING THE SHOE, BUT NOT AS MUCH THIS TIME,

THE FARRIER USES IT TO MELT THE OUTER PART OF THE WALL.

THIS MAKES AN IMPRINT ON THE HORSESHOE

THAT LATER HELPS HIM PLACE IT PROPERLY ON THE HOOF.

HORSES FIRST WEAR SHOES AT ABOUT 3 YEARS OLD,

THE AGE WHEN THEY START WORKING OR COMPETING.

THE FARRIER FINE-TUNES THE FITTING

WITH A METAL FILING TOOL, CURVING THE EDGES FURTHER

TO MAKE THEM EVEN SAFER FOR THE HORSE.

NEXT, HE SHINES THE STEEL WITH A METAL BRUSH.

THE SHINE WILL QUICKLY FADE ONCE THE HORSE TAKES ITS FIRST STEPS.

DEPENDING ON THE FOOT SIZE,

THE FINISHED SHOE CAN MEASURE ANYWHERE

FROM 2.5 TO 9 INCHES ACROSS.

NOW, TO ATTACH THE SHOE, THE FARRIER FIRST FILES THE HOOF

TO REMOVE ANY DUST OR SHARP EDGES.

HE SLIPS ON THE SHOE,

THEN GENTLY HAMMERS AS MANY AS THREE NAILS INTO EACH SIDE.

THE NAILS ARE ABOUT 2 INCHES LONG.

THEY'RE MADE OF LEAD -- A METAL THAT'S EASY TO BEND --

AND THAT'S HE'LL DO AFTER HAMMERING THEM THROUGH THE WALL.

HE CLIPS OFF THE ENDS AND BENDS THE REST IN TOWARDS THE WALL.

THEN HE USES OTHER TOOLS TO GOUGE SMALL CREVICES

IN WHICH TO BURY THE ENDS.

THIS MAKES IT EASY TO STRAIGHTEN OUT THE NAILS

AND YANK OFF THE SHOE WHEN IT'S TIME.

HE ALSO HAMMERS THE HOOF AGAINST A TEMPLATE

TO STABILIZE THE SHOE.

NEXT, HE FILES THE HOOF SO THAT IT MEETS THE ANGLE OF THE SHOE.

AND, FINALLY, THE HORSE IS READY TO STROLL.

SO WHETHER YOU'VE GOT A PONY OR A STALLION,

MAKE SURE THE SHOE FITS.

WHEN IT COMES TO HORSE FOOTWEAR, FUNCTION, NOT FASHION, DICTATES.

Narrator: IN 1886, AN AMERICAN WOMAN

INVENTED THE AUTOMATIC DISHWASHER.

JOSEPHINE COCHRAN BUILT A MOTORIZED WHEEL

WITH WIRE COMPARTMENTS FOR DISHES,

TURNING INSIDE A COPPER TANK FILLED WITH SOAPY BOILING WATER.

IT WAS A HIT WITH RESTAURANTS AND HOTELS,

BUT IT WASN'T UNTIL THE 1950s THAT AFFORDABLE DISHWASHERS

FOR HOME KITCHENS CAME ON THE MARKET.

BUILDING A DISHWASHER

STARTS WITH A WATERTIGHT CONTAINER CALLED THE TUB.

SOME HIGH-END MODELS HAVE STAINLESS-STEEL TUBS.

THE REST HAVE TUBS MADE OF MOLDED PLASTIC,

USUALLY POLYPROPYLENE.

WORKERS SCREW TWO PAIRS OF PLASTIC WHEELS

TO EACH SIDE OF THE TUB.

THEY'LL SUPPORT THE SLIDERS ON WHICH THE UPPER DISH RACK MOVES.

THE LOWER DISH RACK ROLLS ALONG THE BOTTOM OF THE TUB.

THIS STEEL FRAME HELPS SOLIDIFY THE TUB.

THEY AFFIX A STEEL PLATE AT THE BOTTOM

TO SHIELD THE PLASTIC FROM HEAT OF THE MOTOR.

THEN THEY ATTACH STEEL LEGS TO THE FRAME.

HERE, THEY INSTALL A RUBBER RESERVOIR CALLED THE SUMP.

IT COLLECTS THE WATER THAT FLOWS TO THE BOTTOM OF THE TUB.

THEY SCREW IN A TWO-PART RING TO HOLD THE SUMP IN PLACE.

THE HEATING ELEMENT IS A CERAMIC-INSULATED IRON CABLE.

THIS FILTER TRAPS FOOD PARTICLES WASHING OFF THE DISHES.

AFTER FITTING AN O-RING SEAL TO MAKE THE SUMP LEAKPROOF,

THEY SECURE THE HEATING ELEMENT

BY SCREWING CERAMIC INSULATORS TO THE PROTRUDING CONNECTORS.

NOW FOR THE POLYPROPYLENE WASH ARMS.

THIS MODEL HAS ONE AT THE BOTTOM,

WITH A TOWER THAT JUTS OUT FOR A LARGER SPRAY SPAN,

AND A SECOND WASH ARM AT THE TOP.

THE MOTOR PUMPS CLEAN WATER DIRECTLY TO THE BOTTOM WASH ARM

AND, THROUGH THIS FLEXIBLE HOSE, TO THE TOP WASH ARM.

ONCE THEY CONNECT THE HOSE,

THEY SPIN THE WASH ARM TO MAKE SURE THERE'S NO OBSTRUCTION.

MEANWHILE, WORKERS CONNECT KEY COMPONENTS

TO THE DISHWASHER'S CIRCUIT BOARD.

THIS METAL BOX IS THE TIMER.

IT CONTROLS THE WASH AND DRY CYCLES.

FOR EXAMPLE, IT ACTIVATES THIS GREEN CAM LEVER

TO TRIGGER THE WHITE LEVER TO OPEN THE DETERGENT DISPENSER

AT THE RIGHT MOMENT IN THE WASH CYCLE.

THE DETERGENT DISPENSER IS LOCATED ON A PLASTIC PANEL

THAT WILL LINE THE DISHWASHER'S DOOR.

THEY CALL THIS PANEL THE INNER DOOR.

THIS SEAL WILL PREVENT WATER FROM LEAKING OUT

AND ALSO PROVIDE SOME SOUNDPROOFING.

A PRESS RUNS OVER THE INNER DOOR,

DRIVING IN THE SEAL EVENLY ALL AROUND.