All language subtitles for How Its Made S27E09 Combination Squares 1080p AMZN WEB-DL DDP2 0 H 264-SLAG_track4_[eng]

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

CAPTIONS PAID FOR BY
DISCOVERY COMMUNICATIONS

A COMBINATION SQUARE IS
A MEASURING TOOL YOU USE

WHEN BUILDING WITH WOOD,

MASONRY OR METAL

TO MAKE SURE
SOMETHING'S STRAIGHT,

EVEN AND LEVEL.

IT'S ESSENTIALLY A RULER

WITH INTERCHANGEABLE
SLIDING HEADS.

THE MOST BASIC HEAD,
CALLED A SQUARE,

MEASURES 90
AND 45 DEGREE ANGLES.

THIS COMBINATION SQUARE
COMES WITH THREE HEADS.

THEY LOCK INTO A GROOVE
ON ONE SIDE OF THE BLADE.

THE BLADE STARTS
OUT GROOVED BUT BLANK.

SO TO ETCH
THE GRADUATIONS INTO IT,

THEY FIRST COAT THE SURFACES
WITH PHOTORESIST,

A CHEMICAL THAT HARDENS

WHEN EXPOSED
TO ULTRAVIOLET LIGHT.

THEN THEY FLASH UV

LIGHT ON BOTH SIDES
OF THE BLADE

THROUGH POLYESTER FILM NEGATIVES
OF THE GRADUATIONS.

THE LIGHT HARDENS
ONLY THE PHOTO

RESISTANT HITS THROUGH
THE CLEAR PARTS.

THE REST REMAIN SOFT.

AFTER MANUALLY
MASKING THE GROOVE,

WORKERS PUT THE BLADE THROUGH
A PHOTOCHEMICAL ETCHING MACHINE.

IT WASHES OFF
THE SOFT PHOTORESIST

THAT'S IN THE PATTERN
OF THE GRADUATIONS,

THEN HITS THAT BARED STEEL

WITH A METAL-EATING
SALT SOLUTION,

ETCHING THE GRADUATIONS
INTO THE BLADE.

EVERYTHING ELSE IS MASKED
BY HARDENED PHOTO RESIST,

WHICH THEY WASH OFF AFTERWARD.

THE BLADE MEASURES
IN IMPERIAL UNITS.

THEY SET IT IN THIS MACHINE,

WHICH REGISTERS THE LOCATION
OF THE 1-INCH MARK,

THEN GRINDS DOWN
THE END OF THE BLADE

UNTIL IT'S PRECISELY
1 INCH FROM THAT LINE.

THEY RUN THE BLADE
THROUGH A SANDBLASTER.

IT SHOOTS GLASS BEADS
ONTO THE STEEL SURFACE

TO MAKE IT
MICROSCOPICALLY ROUGH.

THIS WILL GIVE THE CHROME
PLATING A MATTE,

RATHER THAN GLOSSY FINISH,

MAKING THE GRADUATIONS
EASIER TO READ.

BEFORE PLATING,

THEY CLEAN THE BLADE
BY DIPPING IT IN ACID.

THEN THEY SUBMERGE IT
IN THE ELECTROPLATING TANK

FOR ABOUT 15 SECONDS.

NOW, THE STEEL BLADE,

WITH ITS GRADUATIONS
ON BOTH SIDES,

IS PLATED IN CHROME.

THE NEXT STEP
IS CALLED BLACK FILLING.

THEY APPLY BLACK ENAMEL PAINT

TO BOTH SIDES OF THE BLADE,

THEN WIPE THE SURFACE CLEAN.

THE BLACK REMAINS
IN THE RECESSED GRADUATIONS,

MAKING THE NUMBERS
AND LINES EASIER TO READ.

FIFTEEN MINUTES IN AN OVEN
TO BAKE ON THE BLACKFILL,

THEN A QUALITY
CONTROL INSPECTION

AND THE BLADE IS FINISHED.

MEANWHILE, IN ANOTHER PART
OF THE FACTORY,

THIS COMPUTER GUIDED
MACHINE USES BOTH MILLING

AND DRILLING TOOLS TO MACHINE

FORGED PIECES
OF STEEL INTO HEADS.

THIS IS THE FORGED SQUARE HEAD,

BEFORE AND AFTER MACHINING
TO ITS FINISHED SHAPE.

THE NEXT STEP
IS TO HARDEN THE STEEL.

THEY PLACE THE HEAD
INTO THE FURNACE FOR 3 MINUTES

AT MORE THAN
1,472 DEGREES FAHRENHEIT.

THE HEAD COMES OUT
COVERED IN BLACK SOOT.

SO THEY SANDBLAST IT CLEAN.

THE SURFACE IS NOW
PREPPED FOR PAINTING.

THE APPLY POWDERED PAINT
ELECTROSTATICALLY,

RUNNING A POSITIVE
ELECTRICAL CHARGE TO THE HEAD

AND A NEGATIVE
ONE TO THE PAINT.

THIS DRAWS THE PAINT
TO THE PART LIKE A MAGNET,

COATING THE ENTIRE SERVICE
IN AN EVEN LAYER.

A 45 MINUTE TRIP THROUGH
AN OVEN BAKES ON THE PAINT.

THEN, THEY MOUNT THE HEAD
ON A COMPUTER-GUIDED MACHINE

THAT GRINDS THAT PAINT OFF

THE HEAD'S
ANGLE-MEASURING SURFACES.

THEY INSTALL
THE HEAD'S BUBBLE LEVEL.

FIRST, THEY INSERT
A WHITE PAPER BACKGROUND,

WHICH MAKES IT EASIER
TO SEE THE AIR BUBBLE.

THEN THEY INSERT THE GLASS
VIAL CONTAINING THE BUBBLE

FLOATING IN A GLUCOSE SOLUTION.

A DAB OF PLASTER AT BOTH
ENDS HOLDS THE VIAL

IN ITS DESIGNATED SLOT.

THEY ASSEMBLE THE LOCK BOLT

THAT HOLDS THE HEAD
IN THE BLADE'S GROOVE.

THEY MOUNT IT WITH A SPRING

AND A WASHER TO PREVENT THE LOCK

FROM ROTATING
AND SECURE IT WITH A NUT.

THEN THEY CLOSE UP THE BUBBLE
LEVEL SLOT WITH AN ENDCAP.

THEY RUN THE UNPAINTED
ANGLE MEASURING SURFACES

AGAINST THE BUFFING WHEEL
TO POLISH THE STEEL TO A SHINE.

THE LAST STEP,

INSERTING A SCRIBING
AWL INTO ITS SLOT.

YOU USE THE AWL
TO MAKE A SCRATCH MARK

WHEN YOU TAKE A MEASUREMENT.

NOW, THE FINAL ASSEMBLY,
THE SQUARE HEAD,

THE PROTRACTOR HEAD

AND THE CENTER HEAD.

ALL THREE COME ON
THE COMBINATION SQUARE.

BUT WHEN USING THE TOOL,
YOU INSTALL ONLY ONE AT A TIME.

NARRATOR: BY THE LATE 1960s,

FISHERMEN JUST COULDN'T KEEP UP

WITH A GROWING GLOBAL
DEMAND FOR SHRIMP.

THIS GAVE BIRTH TO
COMMERCIAL SHRIMP FARMING.

MOST SHRIMP FARMS ARE LOCATED

NEAR THE SEA FOR ACCESS
TO SALT WATER.

THE GREATEST PRODUCER
OF FARMED SHRIMP IS ASIA,

WITH THAILAND BEING
THE LARGEST EXPORTER.

SHRIMP HATCHERIES RAISE
THE OFFSPRING

OF THEIR BREEDING STOCK
THROUGH THREE LARVAL STAGES,

THEN SELL THEM TO SHRIMP FARMS,

WHICH GROW THEM
TO MARKET SIZE.

AS THIS MODEL DEMONSTRATES,

THE SHRIMP FARM FIRST PURIFIES
THE SEAWATER IT USES,

THROUGH A SYSTEM
OF TREATMENT PONDS

CONTAINING FISH
THAT FEED ON MICROORGANISMS.

THEN THE FARM PUMPS
THE TREATED WATER

TO A CULTURE POND,

IN WHICH THE JUVENILE
SHRIMP GROW TO MATURITY.

THIS IS WHAT THE SHRIMP LOOK
LIKE AT ABOUT 2 MONTHS OLD.

SHRIMP FARMS ARE
TYPICALLY LOCATED

ON A COAST FOR SEAWATER ACCESS.

WORKERS SPREAD
ORGANIC FERTILIZER

BEFORE FILLING THE CULTURE POND

TO RESTORE THE SOIL BOTTOM

TO OPTIMUM CONDITIONS
BETWEEN HARVESTS.

THEY PUMP SEAWATER INTO
THE FIRST TREATMENT POND,

WHERE TILAPIA FISH NATURALLY
PURIFY THE WATER BY CONSUMING

FLOATING MICROSCOPIC ORGANISMS
CALLED PLANKTON.

PLANT MATTER
IN FISH FECES SETTLE

AT THE BOTTOM OF THE POND.

A PUMP MOVES WATER FROM THIS

FIRST TREATMENT POND
TO A SECOND ONE.

FOR ANOTHER ROUND OF THIS
NATURAL CLEANING PROCESS.

THEN A PUMP TRANSFERS THE WATER

FROM THE SECOND TREATMENT POND
TO THE CULTURAL POND.

ONCE THE POND IS FULL,

THEY RELEASE THE JUVENILE SHRIMP
PURCHASED FROM THE HATCHERY.

WORKERS REGULARLY MONITOR
THE WATER'S OXYGEN LEVEL

AND RUN AERATION PROPELLERS

WHEN IT DROPS TOO LOW.

THE AGITATION ALSO HELPS

DEBRIS SETTLE AT
THE BOTTOM OF THE POND.

WORKERS RUN A WEEKLY WATER
QUALITY TEST ON SAMPLES

DRAWN FROM THE TREATMENT
AND CULTURE PONDS.

REGULARLY MONITORING
THE CULTURAL POND

IS PARTICULARLY CRITICAL

BECAUSE SHRIMP FECES AND URINE
BREAK DOWN INTO AMMONIA,

WHICH IS TOXIC AT HIGH LEVEL.

THE TEST SOLUTION REACTS
TO THE CONCENTRATION OF AMMONIA

IN THE WATER SAMPLE,

TURNING A SHADE
OF YELLOW OR GREEN.

THEY CONSULT A COLOR CHART
TO TRANSLATE THIS

INTO A MILLIGRAMS
OF AMMONIA PER METER READING.

THEN THEY CONSULT
A TABLE SHOWING SAFE,

DANGEROUS AND TOXIC LEVELS.

IF THE READING IS
ABOVE THE SAFE RANGE,

THEY DILUTE THE AMMONIA

BY PUMPING MORE TREATED WATER

INTO THE CULTURE POND.

ONCE A WEEK, THEY ALSO
PULL A FEW SHRIMP

FROM THE CULTURE POND
TO EXTRACT THEIR LIVERS.

FIRST, THEY EXAMINE
THE SHAPE OF THE ORGAN.

THEY EXAMINE IT UNDER
A MICROSCOPE

TO SEE HOW FATTY IT IS.

A WELL-SHAPED LIVER
WITH SUFFICIENT FAT INDICATES

THE SHRIMP WAS
IN GOOD HEALTH,

AND, THEREFORE, THE OTHERS BACK
IN THE POND ARE TOO.

THE GROWING SHRIMP ARE FED
AN ALL-NATURAL DIET,

WHICH INCLUDES PROBIOTICS,

TAMARIND,

WHICH IS SOAKED IN WATER...

AND GARLIC.

WORKERS ADD THESE THREE
INGREDIENTS TO THE SHRIMP FEED,

WHICH IS A MIXTURE
OF FISH MEAL, FISH OIL,

SOY BEAN PULP AND RICE FLOUR.

TAMARIND MAINTAINS
THE RIGHT LEVEL OF ACIDITY

IN THE SHRIMP'S GUT.

GARLIC PREVENTS BACTERIA
BUILDUP IN THE COLON.

AND THE PROBIOTIC SOLUTION
PROVIDES BENEFICIAL BACTERIA,

WHICH PREVENTS INFECTIONS
AND IMPROVES

HOW THE SHRIMP
DIGESTS NUTRIENTS.

AFTER BLENDING AND LIQUEFYING
THE THREE INGREDIENTS,

THEY MIX IN 6
FLUID OUNCES PER

2 POUNDS OF SHRIMP FEED.

FOUR TIMES A DAY,
AT 8 AM, NOON,

4 PM AND 8 PM,
WORKERS POUR FOOD

ONTO AN AUTOMATIC
FEEDING MACHINE,

WHICH DISTRIBUTES IT EVENLY
THROUGHOUT THE CULTURE POND.

THE SHRIMP FEED OVER
THE ENTIRE 12 HOUR PERIOD,

EATING THE EQUIVALENT
OF ABOUT 4%

TO 5% OF THEIR BODY WEIGHT.

AFTER 4 TO 5 MONTHS
IN THE CULTURAL POND,

THE SHRIMP MATURE
TO MARKET SIZE,

WHICH IS 20 TO 30 GRAMS.

ONCE THEY'RE HARVESTED,

THE FARM DRAINS
THE CULTURE POND

AND STARTS THE PROCESS
ALL OVER AGAIN.

THE BALL VALVE CAME INTO
LARGE SCALE INDUSTRIAL USE

DURING THE 20th CENTURY.

WITH A HOLLOW AND PIVOTING BALL

TO CONTROL THE FLOW OF FLUIDS,

THIS VALVE IS DURABLE
AND RESISTANT TO CONTAMINATION.

IT'S WHY MANY INDUSTRIES
RELY ON BALL VALVES

TO KEEP PRODUCTION FLOWING.

BALL VALVES CONTROL
THE FLOW OF GASES.

IN MACHINERY USED TO PRODUCE
HIGH-TECH PRODUCTS

LIKE LED LIGHTS.

IT'S JUST ONE WAY
THEY CONTRIBUTE

TO THE MODERN WORLD.

MAKING BALL VALVES FOR LED

MANUFACTURING STARTS

WITH AN 11-FOOT
LONG STEEL BAR STOCK.

AS COOLANT, A SAW CARVES
IT UP LIKE SALAMI,

PRODUCING 50 OR 60 STEEL PUCKS.

COMPUTERIZED TOOLING
THEN DRILLS HOLES IN THE PUCKS,

AS IT BEGINS TO TRANSFORM THEM
INTO THE VALVE CENTER PARTS.

THE SYSTEM CHANGES
TOOL BITS AUTOMATICALLY.

CUTTERS SQUARE UP THE PUCKS,

SO THAT THEY'LL FIT IN THE LED
CHIP MAKING MACHINERY.

A GRINDING TOOL MILLS
THE TOPS OF THE PARTS

TO A PRECISE TOLERANCE.

ONCE THE FINAL SHAPE
HAS BEEN ACHIEVED,

A WORKER GIVES
THE PART A SANDING.

HE REMOVES ROUGH BITS,
KNOWN AS BURRS,

AND SMOOTHES THE ENTIRE SURFACE.

WITH A NARROW BLADE,

HE THEN SCRAPES OFF
ANY BURRS IN THE HOLES

THAT COULD IMPEDE
THE VALVE'S FUNCTION.

WITH THE DEBURRING COMPLETE,

HE MEASURES EACH VALVE BODY.

CERAMIC BITS THAT LOOK
LIKE AQUARIUM GRAVEL

WILL NOW BE USED TO POLISH
THE STEEL VALVE PARTS.

THE OPERATOR PLACES
THE VALVE BODIES

IN THE CELLS OF A DRUM TUMBLER.

HE PUTS THE LID ON THE TUMBLER
AND SETS IT IN MOTION.

THE FRICTION POLISHES THE STEEL,

CREATING A SMOOTH SURFACE

THAT WON'T BLOCK THE MOVEMENT
OF GAS MOLECULES.

NEXT, THEY ASSEMBLE FLANGES
TO THE ENDCAPS.

AFTER TACK WELDING
THE TWO PARTS TOGETHER,

AN OPERATOR PLACES THEM
IN A REVOLVING FIXTURE.

HE WELDS THEM TOGETHER,

CREATING A SUBSTANTIAL
INSIDE SEAM

THAT WILL HOLD UP
TO VACUUM CONDITIONS.

HE SCRUBS OFF THE HEAT STAIN
INSIDE THE PART,

USING A WIRE BRUSH.

THE STAIN HAS ALSO SPREAD
AROUND THE SEAMS

ON THE OUTSIDE OF THE PARTS.

SO A WORKER RINSES THE OUTSIDE
OF THE SEAM WITH WATER.

HE WASHES OFF THE STAIN

USING AN ELECTRIFIED
CARBON BRUSH

AND AN ACID CLEANING SOLUTION.

THEN IT'S IN TO
AN ULTRASONIC CLEANER,

WHERE SOUNDWAVES
RIPPLE THROUGH WATER

TO REMOVE DUST
AND CLEANING SOLUTION RESIDUE.

TO ASSEMBLE THE BALL VALVE,

THE TECHNICIAN PLACES

TWO RUBBER O-RINGS
ON TOP OF AN ENDCAP.

NEXT IS A THICK SYNTHETIC RING,

WHICH WILL SECURE
THE BALL IN THE VALVE.

HE SEATS THE VALVE BODY OVER IT.

HE CLEANSES
THE HOLLOW STEEL BALL

AND INSERTS IT
IN THE VALVE BODY.

HE STACKS MORE RUBBER SEALERS,

ANOTHER SYNTHETIC SEALER
AND ANOTHER ENDCAP ON TOP.

HE INSERTS LONG BOLTS
INTO THE FOUR CORNERS

OF THE VALVE

AND SECURES THEM TIGHTLY
WITH NUTS TO KEEP AIR

FROM SEEPING INTO THE VALVE.

HE ATTACHES A HANDLE
TO THE STEM,

PROTRUDING FROM THE VALVE BODY.

HE INSTALLS A STOP PIN
TO PREVENT THE HANDLE

FROM OPENING BEYOND
A QUARTER TURN.

FINALLY, HE TIGHTENS THE NUT
THAT LOCKS THE HANDLE

TO THE VALVE STEM.

HE NOW SECURES THE BALL VALVE
IN A VISE

TO HOLD IT STEADY
WHILE HE TESTS ITS FUNCTION.

WHEN THE WHOLE OF THE BALL
IS ALIGNED WITH FLANGES

OF THE ENDCAPS,
THE VALVE IS OPEN.

AND WHEN IT'S PERPENDICULAR
TO IT, IT'S SHUT.

SATISFIED WITH ITS FUNCTION,

HE TRANSFERS THE BALL VALVE
TO THE LASER ENGRAVER.

THE LASER ETCHES
THE SERIAL NUMBER

AND OTHER INFORMATION
ONTO THE VALVE BODY.

AND NOW, ONE FINAL TEST,

THE TECHNICIAN CONNECTS
THE VALVE

TO A VACUUM PUMPING SYSTEM

AND ACTIVATES
A LEAK-DETECTING DEVICE.

WHILE THE PUMP DRAWS A VACUUM,

HE SPRAYS HELIUM GAS
ONTO THE VALVE

TO DETECT ANY LEAKS.

THIS ENSURES THE VALVE
WILL OPERATE PROPERLY

IN A HIGH VACUUM ENVIRONMENT.

SOME OF THESE BALL VALVES
ARE MANUALLY OPERATED.

AND OTHERS ARE COMPUTERIZED.

BOTH VERSIONS ARE
DESIGNED TO HOLD UP

TO HIGH VACUUM CONDITIONS
AND HANDLE THE FLOW.

Narrator: IF YOU HAVE GRASS
OR WEEDS TO CUT,

BUT CAN'T ACCESS THE SPOT
WITH YOUR LAWN MOWER,

YOU NEED A STRING
TRIMMER FOR THE JOB.

IT'S COMPACT,
LETTING YOU CUT AROUND

AND IN BETWEEN OBJECTS,

AND DOESN'T RIDE
ON THE GROUND.

SO YOU CAN EASILY USE IT
ON A STEEP TERRAIN.

A STRING TRIMMER SLICES
THE VEGETATION IN ITS PATH

WITH A ROTATING NYLON LINE.

THE MOTOR THAT TURNS
THE SPOOL OF LINE

IS PROTECTED BY A TWO-PART
HOUSING MADE OF POLYMER.

THE POLYMER PELLETS ARE PUMPED
THROUGH PIPES TO THE HOPPER,

THAT FEEDS AN INJECTION
MOLDING MACHINE.

THE MACHINE MELTS THEM,

THEN SHOOTS THE LIQUID PLASTIC
INTO HOUSING-SHAPED MOLDS.

THE MACHINE THEN COOLS THE MOLDS
TO SOLIDIFY THE PLASTIC

AND EJECTS THE MOLDED PARTS,

WHICH A ROBOT GRABS AND PLACES
IN A COLLECTION BOX.

TO MAKE OTHER PLASTIC PARTS
OF THE STRING TRIMMER,

THEY INSTALL DIFFERENT MOLDS
ON THE INJECTION MOLDING MACHINE

AND HOOK UP THE FEED LINE

FOR WHICHEVER COLOR PELLETS
THEY'RE USING.

TO MAKE THE CUTTING LINE,

AN EXTRUSION MACHINE MELTS
DOWN PLASTIC PELLETS,

THEN FORCES THE LIQUID
PLASTIC THROUGH

A ROUND DIE TO FORM LINE.

A COLD WATER BATH COOLS
AND SOLIDIFIES THE SHAPE.

THEN, HEATED ROLLERS
STRETCH THE LINE

UNTIL ITS REDUCED
TO 3 MILLIMETERS IN DIAMETER.

THE LINE IS WOUND
ONTO LARGE SPOOLS,

WHICH FEED THE MACHINES

THAT WIND THE FINISHED
TRIMMER SPOOLS.

ON THE ENGINE ASSEMBLY LINE,

AN AUTOMATED MACHINE
APPLIES SEALANT

TO THE MAGNESIUM ENGINE PAN.

THEY PLACE THE CYLINDER

ON AN ASSEMBLY FIXTURE,

APPLY A GASKET,
THEN INSERT THE PISTON.

ALREADY ASSEMBLED
TO THE CRANKCASE,

ITS UP AND DOWN MOTION TURNS.

THEN THEY MATE THE ENGINE PAN
TO THE CRANKCASE.

THE SEALANT IN BETWEEN
MAKING THAT CONNECTION AIRTIGHT.

AN AUTOMATED MACHINE SCREWS
THE COMPONENTS TOGETHER,

THEN CLOSES OFF
THE EXHAUST PORTS

AND PULLS A VACUUM
TO TEST THE SEAL.

IF THE ENGINE ASSEMBLY
PASSES THE TEST,

IT CONTINUES DOWN
THE ASSEMBLY LINE.

THEY INSTALL A GASKET...

THE CARBURETOR...

ANOTHER GASKET

AND THE HOUSING
FOR THE AIR FILTER.

THEN THEY INSTALL A BAFFLE,

WHICH DISTRIBUTES AIR

SO THAT IT ENTERS
THE AIR FILTER EVENLY.

THEY ATTACH A GASKET
UNDER THE MUFFLER

AND SCREW THE MUFFLER
ONTO THE CYLINDER.

THE GASKET AND SEALANT
ON THE SCREWS ENSURE

THE ONLY EXHAUST GASES
CAN ESCAPE THROUGH THE MUFFLER.

NEXT, THE FLYWHEEL.

WHEN IT ROTATES,
MAGNETS INSIDE PRODUCE

AN ELECTROMAGNETIC FIELD
THE IGNITION USES

TO SET OFF THE SPARK PLUG

THAT STARTS THE ENGINE
COMBUSTION CYCLE.

AFTER MOUNTING THE CLUTCH
ON THE FLYWHEEL,

THEY INSTALL THE SPARK
PLUG ON THE CYLINDER.

THIS AUTOMATED MACHINE

SIMULTANEOUSLY TIGHTENS
THE SPARK PLUG,

THE CLUTCH AND THE FLYWHEEL
TO SPECIFIED TORQUES.

BY THIS POINT,
WORKERS HAVE WELDED

A FUEL TANK
TO THE MOTOR HOUSING.

THEY'VE ALSO INSTALLED
A TRIGGER,

A TRIGGER RELEASE,
AND A STOP SWITCH.

THEY PLACE THE ASSEMBLED
ENGINE INTO THE HOUSING.

THEY ALSO PLACE THE AIR FILTER
INTO THE FILTER HOUSING.

AT THE NEXT STATION,

THEY ATTACH THE OTHER
HALF OF THE MOTOR HOUSING.

A ROBOT TIGHTENS THE SCREWS
TO A SPECIFIC TORQUE.

NEXT, THEY SCREW A COVER
ON TO THE FILTER HOUSING.

THEN THEY CREATE
THE TRIMMER'S POWERHEAD

BY INSTALLING
THE STARTER COVER.

IT CONTAINS THE CORD YOU
PULL TO START THE ENGINE.

ELSEWHERE IN THE FACTORY,

THEY BUILD THE SHAFT ASSEMBLY,

TO WHICH THEY'LL LATER
ATTACH THE POWERHEAD.

FIRST, THEY PUT TOGETHER
THE HANDLE IN THE GEARHEAD

THAT TURNS THE SPOOL OF LINE.

THEN THEY INSTALL THE SPOOL.

WHEN THE CUTTING LINE WEARS
DOWN FROM USE,

YOU TAP THE SPOOL
AGAINST THE GROUND

TO AUTOMATICALLY ADVANCE
MORE LINE.

THEY INSERT THE SHAFT
ASSEMBLY INTO THE POWERHEAD.

THE OTHER END OF THE DRIVE
SHAFT CONNECTS TO THE GEARHEAD.

THE LAST STEP IS TO ATTACH
THE GEARHEAD'S DEFLECTOR,

WHICH IS DESIGNED
TO HELP PREVENT

WHAT YOU'RE TRIMMING
FROM FLYING UP AT YOU.

TO USE THE STRING TRIMMER,

YOU FILL THE FUEL TANK
WITH A GAS AND OIL MIXTURE.

THEN, JUST PULL THE CORD
TO START HER UP.