How It's Made

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

LEVELS...

...HOT DOGS...

...ABRASIVE GRAIN...

...AND SANDPAPER.

CAPTIONS PAID FOR BY DISCOVERY COMMUNICATIONS, LLC

THE LEVEL WAS INVENTED IN THE 17th CENTURY

TO KEEP STRUCTURES PLUMB AND TRUE.

WITHOUT IT, BUILDINGS WOULD LEAN,

FLOORS WOULD BE CROOKED,

AND MAPS WOULD HAVE INACCURATE ELEVATION INFORMATION.

NO MATTER WHAT YOU'RE MAKING,

THIS CRITICAL TOOL ALWAYS GIVES IT TO YOU STRAIGHT.

IT'S A CENTURIES-OLD CONCEPT, BUT STILL MEASURES UP.

CENTER THE LITTLE BUBBLE, AND YOU'RE PERFECTLY STRAIGHT.

PRODUCTION BEGINS WITH A LENGTH OF LAMINATED BIRCHWOOD.

AN AUTOMATED ROUTER CARVES OUT SEVERAL HOLES,

THREE OF WHICH WILL ENCLOSE THE VIALS.

THE OTHER TWO WILL SERVE AS HANDGRIPS.

NEXT, IT'S TIME TO TACKLE THE WOOD'S PERIMETER.

GROOVES ARE CUT ALONG THE LENGTH OF THE WOOD

FOR THE LEVEL'S BRASS BINDING.

STRIPS OF BRASS ARE UNWOUND INTO A FORMING MACHINE.

ROLLERS IRON OUT THE CURL FROM THE COILING.

OTHER ROLLERS THEN CRIMP THE BRASS.

THIS PROCESS WILL ALLOW THE STRIP

TO FIT INTO THOSE GROOVES IN THE WOOD.

LENGTHS OF BRASS BINDING

ARE LOADED INTO A MACHINE THAT SLIDES THEM INTO PLACE.

THIS REINFORCES THE EDGES OF THE WOOD.

OVER AT ANOTHER STATION,

A MACHINE MELTS AND MOLDS THE PLASTIC FOR THE VIALS.

EACH ONE IS SLIGHTLY CURVED INSIDE

SO THE BUBBLE HAS A PLACE TO SIT.

THE VIALS WIND THEIR WAY THROUGH A VIBRATORY FEEDER.

IT TAKES THEM TO A GRIPPER

THAT ROTATES EACH ONE SO THE OPEN END FACES UP.

IN GOES A SQUIRT OF YELLOW MINERAL SPIRITS,

LEAVING JUST ENOUGH ROOM FOR A BUBBLE TO FORM.

A ROBOTIC ARM PLUGS THE VIALS WITH PLASTIC CAPS.

THEN THIS SONIC WELDER MELTS THE CAPS ONTO THE VIALS

USING HIGH-FREQUENCY SOUND WAVES.

NOW IT'S TIME FOR INSPECTION.

A TINY CAMERA PHOTOGRAPHS THE BUBBLE

AND SENDS THE PICTURE TO A COMPUTER

THAT MAKES SURE THE BUBBLES ARE THE RIGHT SIZE.

FOR THIS PRODUCTION RUN,

THE BUBBLE SHOULD BE ABOUT HALF AN INCH WIDE.

IF IT'S ON THE MARK,

THE COMPUTER ALLOWS THE VIAL TO MOVE ON.

A PRINTER THEN HOT-STAMPS CENTERING MARKS ONTO THE VIAL.

BUT THIS SPIRIT VIAL ISN'T QUITE READY FOR BUSINESS.

FIRST IT NEEDS TO BAKE FOR 24 HOURS.

THE HEAT EXPOSES ANY FLAWS,

AND THE DEFECTIVE VIALS ARE REJECTED.

THE VIAL IS ILLUMINATED WITH A BRIGHT RED LIGHT

AS IT SLOWLY SPINS BETWEEN ROLLERS.

A CAMERA PHOTOGRAPHS THE BUBBLE,

AND A COMPUTER SCANS THE IMAGE TO CHECK FOR SHIFTING.

TOO MUCH SHIFTING COULD COMPROMISE THE LEVEL'S ACCURACY.

THE VIALS THAT PASS THE TEST THEN GO ON TO A MOLDING SYSTEM.

MELTED PLASTIC IS INJECTED INTO THE CREVICES

TO MAKE A CRADLE FOR EACH VIAL.

NEXT, A TECHNICIAN GLUES THE CRADLED VIALS

IN THE OPENINGS IN THE WOODEN FRAMEWORK.

THIS IS PRECISION WORK.

EACH VIAL HAS TO SIT PERFECTLY LEVEL,

SO TECHNICIANS RELY ON A MAGNIFIED IMAGE

TO CHECK THEIR PROGRESS.

SOME VIALS ARE INSTALLED VERTICALLY

TO GAUGE IF THE WALLS ARE PLUMB,

WHILE THE HORIZONTAL ONES LET YOU KNOW IF THE FLOOR IS LEVEL.

ACRYLIC-RIMMED WINDOWS ARE FITTED OVER THE VIALS

TO PROTECT THEM.

RUBBER CAPS ARE SCREWED ON TO BOTH ENDS OF THE LEVEL.

AND FINALLY, THE TRADEMARK STAMP GOES ON.

THESE LEVELS ARE NOW READY TO STRAIGHTEN UP ANY JOBSITE.

WHEN WE RETURN, THE REAL SKINNY ON AN ALL-AMERICAN FAVORITE.

Narrator: HOT DOGS ARE AN ALL-AMERICAN FARE.

BUT MOST LIKELY IT WAS GERMAN SAUSAGE MAKERS

WHO FIRST CAME UP WITH THE IDEA.

IN FACT, THERE ARE REPORTS OF GERMAN IMMIGRANTS

SELLING THEM FROM PUSHCARTS IN NEW YORK'S BOWERY

AS FAR BACK AS THE 1860s.

A CENTURY AND A HALF LATER,

HOT DOGS ARE STILL THE NUMBER-ONE TREAT ON THE STREET.

TRADITIONAL HOT DOGS

ARE MADE FROM A MIX OF PORK, BEEF, AND CHICKEN.

THE CUTS THEY START WITH ARE CALLED TRIMMINGS --

PIECES OF MEAT LEFT OVER FROM CUTTING STEAKS OR PORK CHOPS.

THE TRIMMINGS ARE GROUND

THE SAME WAY BUTCHERS CHOP UP HAMBURGER MEAT --

BY PUSHING THE CUTS THROUGH GRATED METAL PLATES.

PROCESSED CHICKEN TRIMMINGS ARE ADDED TO THE GROUND MEAT,

FOLLOWED BY FOOD STARCH, SALT, AND OTHER FLAVORINGS.

THESE FLAVORINGS VARY

DEPENDING ON WHERE THE HOT DOGS ARE TO BE SOLD

BECAUSE PEOPLE IN DIFFERENT REGIONS HAVE DIFFERENT TASTES.

WATER IS SPRAYED INTO THE MIX,

AND EVERYTHING IS BLENDED TOGETHER IN A BIG VAT.

CORN SYRUP ADDS A DASH OF SWEETNESS.

THE ADDITION OF EVEN MORE WATER

HELPS TO DISPERSE THE INGREDIENTS

AND MAKE THE HOT DOGS JUICIER.

ANOTHER MACHINE THEN PUREES THE MEAT BATTER

INTO A FINE EMULSION AND VACUUMS OUT ANY AIR.

LONG ROLLS OF CELLULOSE TUBING

ARE LOADED INTO THE STUFFING MACHINE.

IT PUMPS THE MEAT PUREE INTO THESE CASINGS,

TWISTING IT EVERY 5 1/4 INCHES --

THE LENGTH OF ONE HOT DOG.

IT TAKES JUST 35 SECONDS

TO MAKE A CHAIN OF HOT DOGS THAT WOULD SPAN A SOCCER FIELD TWICE.

THEN THREE OF THOSE HOT-DOG CHAINS

ARE LINKED TOGETHER TO MAKE AN EVEN LONGER STRING,

AND THEY'RE LOADED SEVERAL AT A TIME INTO ANOTHER MACHINE,

WHICH DRAPES THE HOT DOGS ONTO MOVING RACKS.

THE PROCESS IS CAREFULLY TIMED

SO THAT A TWIST ALWAYS LANDS ON THE BAR.

THE RACKS SHUNT THE HOT DOGS THROUGH A LIQUID SMOKE SHOWER,

THEN INTO AN OVEN WITH SEVERAL COOKING ZONES.

THE LIQUID SMOKE SEEPS THROUGH THE CASING

AND ADDS FLAVOR TO THE DOGS AS THEY BAKE.

HOT OUT OF THE OVEN,

THESE FRANKS ARE DRENCHED IN COLD, SALTY WATER

TO CHILL THEM IN PREPARATION FOR PACKAGING.

THE HOT DOGS THEN FILE DOWN TO AN UNLOADING ZONE.

HERE, A MACHINE PULLS THEM OFF THE BARS ONTO A CONVEYOR.

THEN THE HOT DOGS SLIDE OFF THE CONVEYOR INTO METAL CONTAINERS.

IF YOU'VE BEEN WONDERING

ABOUT THOSE BLACK STRIPES ON THE CASINGS,

ALL IS ABOUT TO BE REVEALED.

THE STRIPE IS A MARKER ATTACHED TO THE CASING.

THE ABSENCE OF A BLACK STRIPE

MEANS THE HOT DOG IS COOKED AND READY FOR PACKAGING.

INSIDE THE PEELER MACHINE,

A TINY KNIFE SLITS EACH CASING ALONG THE TOP.

THEN STEAMY AIR BLOWS THE CASINGS RIGHT OFF THE DOGS.

THIS MACHINE PEELS 700 HOT DOGS A MINUTE.

AN INSPECTOR MAKES SURE

THE CASING HAS BEEN COMPLETELY REMOVED

AND THAT THERE ARE NO DEFECTS IN THE DOGS.

THEN IT'S INTO A DEVICE

THAT LOOKS LIKE A PLASTIC BICYCLE CHAIN.

THE SPROCKETS POSITION THE HOT DOGS FOR PACKAGING.

THIS FACTORY MANUFACTURES

AN INCREDIBLE 300,000 HOT DOGS AN HOUR.

THAT'S CLOSE TO 2 1/2 MILLION PER SHIFT.

THEY REALLY DO CHURN THEM OUT LIKE SAUSAGES.