Original subtitles

--Captions by VITAC-- www.vitac.com

CAPTIONS PAID FOR BY DISCOVERY COMMUNICATIONS

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

METAL NAIL FILES.

BIRCH BARK CANOES.

CRUISER BOAT HARDTOPS.

AND HIGH-VOLTAGE CIRCUIT BREAKERS.

THROUGHOUT HISTORY, PEOPLE HAVE WANTED NICE NAILS.

AND THEY USED WHATEVER THEY COULD GET THEIR HANDS ON

TO MAKE THEM LOOK GOOD.

MARIE ANTOINETTE IS SAID TO HAVE USED A PUMICE STONE FILE

TO SHAPE HER FINGERNAILS.

BY THE END OF THE 19th CENTURY,

METAL NAIL FILES BECAME THE NORM.

METAL NAIL FILES CAN BE USED TO GRIND

AND SHAPE FINGERNAILS WITH A FEW STROKES.

THEIR ABRASIVENESS IS THE SECRET TO THEIR POPULARITY.

MAKING METAL NAIL FILES STARTS

WITH A THICK SPOOL OF STAINLESS STEEL.

THE STEEL UNWINDS AT A STEADY PACE.

A PUNCH PRESS WIELDS 88 TONS OF HYDRAULIC PRESSURE

TO CUT OUT NAIL FILE BLANKS.

THE BLANKS SPILL INTO A BIN AND ACCUMULATE.

THE BLANKS BOUNCE AROUND WITH CERAMIC STONES

AND A MIX OF WATER AND POLISHING SOLUTION.

THIS SMOOTHES THE ROUGH BITS ON THE BLANKS

AND ALSO CLEANS THEM.

THE NAIL FILE BLANKS THEN SLIDE DOWN A CHUTE INTO A DRYER.

THIS DRYER DOESN'T USE HOT AIR TO DO THE JOB.

INSTEAD, A PULSATING MASS OF HOT CORN GRAIN

SOAKS UP THE LINGERING LIQUID ON THE BLANKS.

AS THE BLANKS EXIT, SOME OF THE CORN FALLS

THROUGH A PERFORATED CONVEYOR TO BE REUSED.

THE BLANKS CONTINUE ON AND LAND IN A BIN,

READY FOR THE NEXT PHASE OF PRODUCTION.

IT INVOLVES THE CUTTING OF AN ABRASIVE GRID ON BOTH SIDES.

IT'S A THREE-STAGE PROCESS.

FIRST, A WORKER PLACES THE BLANK UNDER A SHARP TOOL

THAT'S ANGLED AT 52 DEGREES.

THE TOOL POUNDS THE BLANK REPEATEDLY

TO CUT ANGLED GROOVES INTO IT.

HERE IS THE BLANK BEFORE

AND AFTER THE FIRST CUT.

HE SWITCHES THE CUTTING TOOL,

AND IT CARVES OVER THE FIRST CUTS ON THE OPPOSITE ANGLE.

THE THIRD CUT GOES STRAIGHT ACROSS THE OTHER TWO.

THE RIDGES AND VALLEYS CREATED BY THE CROSS CUTS

MAKE THE SURFACE OF THE BLANK SHARP.

THE GRID CUTTING HAS BENT

THE STILL-PLIABLE STEEL OUT OF SHAPE,

SO THE WORKER NOW BENDS THE NAIL FILES IN THE OPPOSITE DIRECTION,

USING A ROUND FORM AS A GUIDE.

THIS RESTORES THEIR LINEAR PROFILE.

THE CARVING PROCESS HAS ALSO CAUSED STEEL TO BULGE

ON THE EDGES OF THE NAIL FILES,

SO HE GRINDS THEM AGAINST A FINE ABRASIVE SANDING BELT

TO MAKE THE EDGES SMOOTH AGAIN.

NEXT, HE PLACES THE METAL NAIL FILES

IN PERFECT ALIGNMENT IN A TRAY.

HE TRANSFERS THE TRAY OF FILES TO AN OVEN.

THE FILES BAKE FOR AN HOUR

AT A TEMPERATURE OF 1,832 DEGREES FAHRENHEIT.

THE INTENSE HEAT BEGINS TO ALTER

THE PHYSICAL PROPERTIES OF THE STEEL

AND IS THE FIRST PHASE OF A HARDENING PROCESS.

WHEN THE HOUR IS UP,

HE TAKES THE RED-HOT TRAY OF NAIL FILES

OUT OF THE OVEN USING TONGS

AND THEN IMMERSES THEM IN A VAT OF COLD SALTWATER.

THIS IS CALLED QUENCHING.

THE SHOCK OF THE QUENCH COMPLETES THE HARDENING PROCESS.

SHIELDED BY AN ENCLOSURE,

HE SANDBLASTS EACH NAIL FILE TO REMOVE STAINS

LEFT BY THE HARDENING PROCESS

AND TO MAKE THE STEEL AROUND THE TRIPLE-CUT GRID SHINIER.

HE PLACES THE HANDLE INTO THE NAIL FILE

BENEATH A PLASTIC STENCIL.

A STAMP APPLIES ACID TO THE OPEN AREAS OF THE STENCIL

TO ETCH BRAND INFORMATION ONTO IT.

SOME NAIL FILES HAVE PLASTIC HANDLES.

TO MAKE THE HANDLES,

THIS MACHINE MELTS PLASTIC AND INJECTS IT INTO MOLDS.

THE HANDLES ARE STUCK TOGETHER

BY HARDENED FLOW LINES OR RUNNERS.

A FEW TUMBLES IN THIS REVOLVING DRUM KNOCKS OFF THE RUNNERS,

SEPARATING THE HANDLES FROM THEM.

THE WORKER PLACES EACH HANDLE UNDER AN AUTOMATED PRINTING HEAD

THAT SOAKS UP INK FROM A PAD

AND THEN STAMPS BRAND INFORMATION ONTO THE PLASTIC.

ANOTHER WORKER HEATS THE END OF EACH METAL NAIL FILE

USING COPPER ELEMENTS.

SHE INSERTS THE HOT METAL INTO THE PLASTIC SLEEVE,

AND THE PLASTIC MELTS A LITTLE TO BOND TO THE METAL.

THESE METAL NAIL FILES ARE READY FOR THE GRIND.

Narrator: FOR CENTURIES, THE CANOE WAS INDISPENSABLE

TO THE INDIGENOUS PEOPLE OF NORTH AMERICA.

ESSENTIAL FOR HUNTING, FISHING, TRANSPORTATION, AND COMMERCE,

INDIGENOUS PEOPLE OFTEN CRAFTED THEIR CANOES FROM BIRCH BARK,

WHICH IS LIGHTWEIGHT, STRONG, WATERPROOF, AND ROT-RESISTANT.

HISTORICALLY, DIFFERENT INDIGENOUS TRIBES

CONSTRUCTED DIFFERENT STYLES OF BIRCH BARK CANOES.

THIS ONE IS THE TYPE CRAFTED BY

BOTH THE ALGONQUIAN AND EASTERN OJIBWE.

EVEN TODAY, THE CANOE BUILDER CRAFTS EVERY COMPONENT

FROM WATER- AND ROT-RESISTANT PLANT MATERIALS

FOUND IN THE FOREST,

SUCH AS THE EXCEPTIONALLY STRONG ROOTS OF BLACK SPRUCE TREES.

AFTER SCRAPING OFF THE BARK

WITH A TOOL CRAFTED FROM A MOOSE RIB,

THIS CRAFTSWOMAN CUTS A SLIT IN THE TOP AND PULLS,

SPLITTING THE LONG ROOT INTO TWO STRIPS.

SHE COILS UP EACH STRIP AND PUTS IT ASIDE TO DRY OUT.

THE CANOE BUILDER USES SPRUCE ROOT

TO BIND STRUCTURAL COMPONENTS

AND LACE TOGETHER SECTIONS OF BIRCH BARK.

TO BUILD THE CANOE'S CEDAR STRUCTURE,

THE BUILDER CONNECTS END FRAMES AT THE FRONT AND BACK

WITH LONG STRIPS OF CEDAR CALLED GUNWALES,

THEN HE LASHES CROSSBARS CALLED THWARTS

TO THE GUNWALES WITH SPRUCE ROOT.

TO MAKE EACH END FRAME,

HE SPLITS A PIECE OF CEDAR MANY TIMES TO LET IT BEND,

SOAKS IT IN BOILING WATER TO SOFTEN THE WOOD FIBERS,

AND BINDS THE SHAPE WITH SPRUCE ROOT.

THEN THE BUILDER CHECKS THIS CURVED PART, CALLED THE STEM,

AGAINST THE STRAIGHT PART, CALLED THE HEADBOARD.

IF THE PROPORTIONS ARE RIGHT,

HE NOTCHES THE BOTTOM OF THE HEADBOARD

TO FIT OVER THE BASE OF THE STEM,

THEN LASHES THE PARTS TO EACH OTHER WITH SPRUCE ROOT.

HE LACES TOGETHER SEVERAL PIECES OF BIRCH BARK

TO MAKE A SHEET LARGE ENOUGH FOR THE CANOE.

THE BUILDER SATURATES THE BARK SHEET WITH BOILING WATER

AND BENDS IT UP AROUND A WOODEN TEMPLATE.

THEN, ON EACH SIDE OF THE CANOE,

HE SANDWICHES THE TOP EDGE OF THE BARK

IN BETWEEN THE TWO CEDAR STRIPS THAT FORM THE GUNWALE.

THE BUILDER SHAVES PIECES OF CEDAR

TO MAKE STRAIGHT, VERTICALLY LAID PLANKS

AND U-SHAPED HORIZONTALLY LAID RIBS

THAT LINE THE INSIDE OF THE CANOE.

HE USES A GAUGE TO MAKE SURE

EACH PIECE IS THE REQUIRED THICKNESS.

HE LAYS EACH RIB PIECE ACROSS THE STRUCTURE

AND MAKES A MARK ON EACH SIDE

IN LINE WITH THE BOTTOM EDGE OF THE FLOOR.

THAT'S WHERE HE'LL BEND THE PIECE.

JUST AS HE DID TO BEND THE STEM PORTION OF THE END FRAME,

THE BUILDER LADLES BOILING WATER ONTO THE WOOD

TO SOFTEN THE FIBERS.

HE POSITIONS HIS KNEES ON THE CHARCOAL MARKS

AND PULLS UP THE ENDS.

HE BENDS TWO RIBS AT A TIME,

AS THIS REDUCES THE CHANCES OF THEM CRACKING.

AFTER CHECKING THAT HE CUT AND BENT ALL THE RIBS CORRECTLY,

THE BUILDER BEGINS THE PROCESS OF SECURING THE BIRCH BARK.

HE DRILLS HOLES IN THE GUNWALES AT NEARLY SIX-INCH INTERVALS.

THEN HE TAKES PEGS CARVED FROM HARDWOOD

SUCH AS ASH OR MAPLE

AND HAMMERS ONE THROUGH EACH HOLE.

THEN HE PIERCES HOLES THROUGH THE BARK

WITH A TRADITIONAL AWL MADE FROM DEER ANTLER.

HE THREADS SPRUCE ROOT THROUGH THE HOLES

TO LASH THE BARK TO THE GUNWALE.

WITH AN ASSISTANT'S HELP,

HE FULLY LINES THE CANOE WITH STRAIGHT CEDAR PLANKS

AND INSTALLS THE REMAINING RIBS.

THE TIGHT FIT PRESSES THE PLANKS AGAINST THE BARK,

STRETCHING IT TAUGHT, WHICH STRENGTHENS IT.

THE FINAL STEP IS KNOWN AS PITCHING THE SEAMS.

HE MELTS DOWN DRIED RESIN

GATHERED FROM SCARS ON SPRUCE TREES

AND MIXES IN TWO INGREDIENTS --

GROUND CHARCOAL

AND OIL RENDERED FROM BEAR FAT.

HE APPLIES THIS HOT MIXTURE

TO ALL THE LACING HOLES IN THE BIRCH BARK,

MAKING THE CANOE WATER-TIGHT.

THE CANOEIST CARRIES A SMALL SUPPLY OF DRIED PITCH

AND LIGHTS A STICK TO REMELT AND APPLY IT.

THE REPAIR DRIES QUICKLY,

SO IN ABOUT FIVE MINUTES,

THE CANOEIST CAN BE BACK IN THE PADDLE.

Narrator: A HARDTOP ENCLOSES THE COCKPIT OF A CRUISER BOAT.

IT PROVIDES SHELTER FROM WATER SPRAY, WIND, AND SUN,

AND A ROOF ON WHICH TO MOUNT ANTENNA FOR MARINE

AND SATELLITE RADIO AND GPS.

ON THE INSIDE, IT PROVIDES WALLS AND A CEILING

FOR RECESSED LIGHTING AND OTHER FEATURES.

THIS CRUISER HARDTOP HAS WINDOWS

THAT WRAP AROUND THE FRONT AND SIDES.

THE TALL ONE IN THE MIDDLE IS RETRACTABLE

SO YOU CAN WALK THROUGH TO THE FRONT DECK.

WORKERS USE TWO MOLDS TO MAKE THE INNER AND OUTER PARTS

THAT FORM THE HARDTOP.

FIRST, THEY SPRAY WHITE GELCOAT

TO A THICKNESS OF JUST .6 MILLIMETERS.

NEXT, WORKERS SHOOT SHREDDED FIBERGLASS STRANDS INTO THE MOLD

ALONG WITH A STREAM OF RESIN WHICH SATURATES THE FIBERS.

WHEN THE FIBERGLASS IS ABOUT 3/4 OF AN INCH THICK,

THEY LET THE RESIN CURE FOR AN HOUR OR SO.

THEN WORKERS APPLY BONDING PUTTY TO THE FIBERGLASS

IN THE OUTER MOLD.

THEY MATE THE INNER AND OUTER MOLDS

AND LET THE PUTTY SET,

WHICH TAKES ABOUT AN HOUR.

FINALLY, IT'S TIME TO EXTRACT THE FIBERGLASS FROM THE MOLDS.

IT COMES OFF RELATIVELY EASILY

BECAUSE PRIOR TO SPRAYING THE GELCOAT LAYER,

WORKERS HAVE APPLIED A RELEASE AGENT ON THE MOLD'S SURFACE.

THE INNER AND OUTER PARTS ARE BUILT IN THE MOLD UPSIDE-DOWN

SO THE GELCOAT GIVES THE COARSE FIBERGLASS

A SMOOTH AND SHINY SURFACE FINISH.

THEN THEY CUT OPENINGS FOR THE WINDOWS

AND FOR THE VARIOUS COMPONENTS

TO BE INSTALLED INTO THE HARDTOP.

THEY INSTALL THE RETRACTABLE FRONT WINDOW.

WORKERS THEN POSITION THE WINDOW AND MARK THE SCREW HOLES,

THEN REMOVE IT IN ORDER TO APPLY ADHESIVE,

WHICH ALSO FUNCTIONS AS A SEALANT

TO PREVENT WATER INFILTRATION.

THEY RESET THE WINDOW AND SCREW IT TO THE HARDTOP.

WORKERS INSTALL A NON-OPENING WINDOW

ON EACH SIDE OF THE RETRACTABLE ONE.

AFTER TAPING OFF THE AREA, A WORKER APPLIES PRIMER.

ONCE THE PRIMER DRIES, THEY REMOVE THE TAPE

AND APPLY AN ADHESIVE-BACKED FOAM GASKET

THAT'S ABOUT 1/4-INCH HIGH.

A WORKER APPLIES A 1/4-INCH HIGH BEAD OF ADHESIVE SEALANT

NEXT TO THE GASKET AND SETS THE WINDOW.

THE PRIMER GASKET AND ADHESIVE SEALANT

ARE ALL BLACK TO MATCH THE WINDOW FRAME.

ON THE ROOF OF THE HARDTOP,

WORKERS INSTALL A THIN MOLDED FIBERGLASS COVER.

THE RETRACTABLE WINDOW, WHEN OPENED, SLIDES UNDER IT.

WORKERS FILL THE GAP

BETWEEN THE COVER AND HARDTOP WITH SEALANT.

THIS ADHERES THE COVER AND MAKES IT WATERTIGHT.

AT THE REAR, WORKERS INSTALL THE RADAR ARCH.

THIS, TOO, IS MADE OF MOLDED FIBERGLASS

BUT WITH A BLACK GELCOAT FINISH.

THEY MOUNT VARIOUS COMPONENTS ON IT,

SUCH AS THE HORN, NAVIGATION LIGHT, AND ANTENNA.

INSIDE THE HARDTOP,

AFTER PASSING WIRES FOR LIGHTING,

WORKERS CONNECT THE WIRING TO THE RETRACTABLE WINDOW.

THE WINDOW COMES AS A SELF-CONTAINED UNIT

WITH AN INCORPORATED MOTOR AND INTRICATE PULLEY SYSTEM.

THE HARDTOP IS NOW READY TO BE MOUNTED TO THE CRUISER'S DECK.

WORKERS INSTALL A WINDSHIELD WIPER

ON EACH NON-OPENING FRONT WINDOW.

THE LAST STEP IS TO INSTALL A LARGE WINDOW

ON BOTH SIDES OF THE HARDTOP.

ITS MIDDLE SECTION OPENS.

LIKE A GIANT WINDSHIELD,

THE HARDTOP TRANSFORMS THE CRUISER BOAT'S

OTHERWISE OPEN COCKPIT

INTO A WEATHER-PROTECTED LOUNGE.

Narrator: ELECTRICAL SUBSTATIONS PLAY A CRITICAL ROLE IN THE GRID

AS THEY DISTRIBUTE ELECTRICITY TO ENTIRE COMMUNITIES.

THE CIRCUIT BREAKERS AT THESE STATIONS

ROUTINELY INTERRUPT SHORT CIRCUITS

TO PREVENT DAMAGE TO THE SYSTEM.

THEY PERFORM THE SAME FUNCTION

AS THE ONES IN A HOME ELECTRICAL PANEL,

BUT ON A MUCH LARGER SCALE.

THE SIZE OF A CAR OR EVEN A LARGE TRUCK,

THESE CIRCUIT BREAKERS TROUBLESHOOT

HIGH-CURRENT SITUATIONS AT ELECTRICAL SUBSTATIONS.

THIS PROTECTS THE GRID AND PREVENTS POWER OUTAGES.

MAKING ONE STARTS WITH A CAST-ALUMINUM TANK

THAT HAS RECEPTACLES FOR BUSHINGS.

A WORKER INSPECTS THE TANK FOR DIRT OR FLAWS

AND THEN PLACES PROTECTIVE COVERS

ON THE BUSHING RECEPTACLES.

HE INSTALLS BASES FOR CURRENT TRANSFORMERS

ON THESE RECEPTACLES.

THE WORKER APPLIES ADHESIVE

TO THE OUTSIDE OF THESE METAL BASES.

HE PRESSES SQUARES OF PLASTIC INSULATION TO THE GLUED AREAS.

WITH THE HELP OF AN OVERHEAD LIFT,

THE WORKER INSTALLS THE TWO CURRENT TRANSFORMERS

ON THE INSULATED BASES.

THESE CURRENT TRANSFORMERS WILL ACT AS SENSORS,

ENABLING THE CIRCUIT BREAKER TO DETECT SHORT CIRCUITS

IN AN ELECTRICAL SYSTEM IN MERE MILLISECONDS.

ANOTHER WORKER BRUSHES LUBRICANT

ON THE MOVING PART OF THE INTERRUPTER

THAT WILL BREAK THE ELECTRICAL CURRENT WHEN NEEDED.

HE INSERTS THE EXHAUST TUBE

THAT HELPS DIRECT THE FLOW OF GAS USED TO BREAK THE CURRENT.

HE SETS THE INTERRUPTER MODULE

IN AN UPRIGHT POSITION ON THE FLOOR

AND RETURNS TO THE WORKBENCH.

THE WORKER DABS THREAD LOCK LIQUID IN THE MOUNTING HOLES

OF THE STATIONARY CONTACT ASSEMBLY

AND INSTALLS A RESIN RING IN THE BASE.

HE INSERTS THE STATIONARY PART INTO THE MOVING ONE,

LEAVING THE END PROTRUDING.

THE WORKER APPLIES THREAD LOCK

TO THE ASSEMBLY HOLES OF A LARGE TUBE

THAT WILL SHIELD THE ENTIRE INTERRUPTER

ONCE IT'S INSTALLED IN THE TANK.

IT WILL ALSO DIRECT THE FLOW OF INTERRUPTING GAS.

AFTER ASSEMBLING IT TO THE INTERRUPTER,

HE INSERTS A SYNTHETIC INSULATING TUBE.

THEN WITH THE HELP OF A LIFT,

HE FLIPS THE MODULE OVER

IN ORDER TO WORK ON THE OTHER END.

HE INSTALLS ANOTHER INSULATING TUBE IN THIS END.

HE THEN SETS THE MODULE TO A STAND TO STEADY IT

AS HE INSERTS THE CONTACT ASSEMBLY

THAT OPENS TO INTERRUPT THE ELECTRICAL CURRENT.

HE CAPS ONE END OF THE INTERRUPTER

WITH THE UNIT THAT HOUSES THE BELL CRANK.

HE SLIDES THE BELL CRANK INTO THE HOUSING.

THIS CRANK WILL CONVERT THE ROTARY MOTION

FROM THE OPERATING MECHANISM TO A LINEAR MOTION.

HE TURNS THE CRANK TO CONFIRM THAT IT ROTATES FREELY.

HE NOW CLAMPS LEADS TO TEST PROBES

INSERTED IN THE INTERRUPTER

AND APPLIES 100 AMPS OF CURRENT.

THE TESTING DEVICE MEASURES THE INTERRUPTER'S RESISTANCE

TO THE CURRENT TO CONFIRM THAT

IT'S WITHIN AN ACCEPTABLE RANGE.

WITH A LIFT BEARING THE LOAD,

THE OTHER MEMBER OF THE TEAM GUIDES THE INTERRUPTER MODULE

INTO THE CAST-ALUMINUM TANK.

HE BOLTS THE BELL CRANK'S HOUSING TO THE TANK OPENING

AND PLACES CYLINDRICAL ELECTRICAL SHIELDS

IN EACH OF THE BUSHING RECEPTACLES.

HE THEN ENCASES THE TRANSFORMERS AT THE BASE

WITH ALUMINUM COVERS.

THEY'LL PROTECT THE TRANSFORMER WIRING

FROM RAIN, SNOW, OR DIRT.

LIFTS NOW HOIST THE SILICONE-RUBBER-WRAPPED BUSHINGS

INTO THE RECEPTACLES.

THE WORKER BOLTS THEM IN PLACE...

...AND CAPS THE REAR OF THE TANK.

THIS INTERRUPTER IS NOW READY

TO BE MOUNTED TO THE STEEL SUPPORT STRUCTURE.

EACH HIGH-VOLTAGE CIRCUIT BREAKER

WILL BE EQUIPPED WITH THREE INTERRUPTERS.

THE TEAM CONNECTS THE BELL CRANKS

TO THE OPERATING SYSTEM IN THE CONTROL CABINET.

AND WORKERS EQUIP EACH BELL CRANK WITH A PRESSURE GAUGE.

A WORKER GROUNDS THE CIRCUIT BREAKER

TO THE SUPPORT STRUCTURE WITH COPPER CABLES.

THIS WILL PREVENT SHOCKS TO ANYONE WHO TOUCHES IT.

IN ONE LAST TEST,

TOWERING TRANSFORMERS APPLY HIGH VOLTAGES

TO THE CIRCUIT BREAKERS.

THESE HIGH-VOLTAGE CIRCUIT BREAKERS

ARE READY TO INTERRUPT SITUATIONS

BEFORE THEY BECOME PROBLEMS.