07x08 - Inflatable Safety Devices/Braille Typewriters/Carbon Fibre Cellos

[bunniefuu]

Narrator:
today on "how it's made"...

Inflatable safety devices...

...braille typewriters...

...and carbon-fiber cellos.

They're designed
to keep your head above water.

Inflatable safety devices
activate in seconds

To buoy you up and keep you
afloat until help arrives.

You'll find these survival
devices on airplanes and boats.

Even when they're not inflated,

They provide piece of mind

That you'll be safe
while on the water.

To make a life vest,

A computer-controlled knife
cuts a pattern

In urethane-coated nylon.

Heat from the blade makes
some pieces stick together,

So a worker peels them apart.

The shiny side
is the waterproof coating.

It'll be on the inside
of the life vest.

They place the front of the vest

On a vacuum table
to hold it down.

Then they silk-screen
the amount of carbon dioxide

Needed for inflation
onto the fabric.

Next, they pull
an oral inflation tube

Through a precut hole...

...and then place the assembly
under a radio-frequency press.

It emits energy that heat-seals
the tube to the fabric.

They fasten the back
and front vest pieces

On pegs to align them.

She slides the table
with the vest pieces

Under a big
radio-frequency press.

Again, electromagnetic energy
bonds the plastic pieces.

This vest has been put together
without a single stitch.

The cylinder that contains
the carbon dioxide

Has been installed.

It holds about one ounce
of the gas under pressure,

Which will instantly inflate
the vest with one tug on a tab.

It also activates automatically
when immersed in water.

A little tablet inside
dissolves,

Triggering a spring
that punctures the cylinder.

Pull the cord on this pack,

And you'll have an instant
lifeboat, complete with a roof.

To make one,
the computerized blade

Cuts shapes out
of rubberized fabric,

While a plastic film
helps hold it in place.

They brush on a rubber adhesive
to seal the boat's joints

And press rubber tape
over the glue.

They remove air bubbles.

It will take several days
for the bonding to be complete.

They apply
the same rubber adhesive

To all the inflation valves
and pressure tubes.

To help activate the glue,
they wipe it with a damp rag,

Then insert a valve
through a hole

In one of the raft's
air chambers.

They apply more glue
to the outside around the valve

And secure it with a ring
called a doubler.

It really is the glue that holds
everything together.

They apply more rubber adhesive

Onto the lower inflated chamber.

Then they stretch a sheet
of rubber flooring over it.

They smooth down the edges,
again, to remove air bubbles.

They run rubberized tape
around the rim.

It will protect it
and also act as a hinge

Between the floor
and the upper air chamber,

Which will go on next.

In preparation for that,

They measure to align
all the inflation valves.

Then they pull
the upper air chamber,

The walls of the raft, on top
of the floor and lower chamber.

They line up the valves
but hold off on connecting them.

Next, they pump regular air
into the upper chamber

To test the shape and function.

A plastic strip has been
keeping the glued surfaces

From contacting.

They pull it out and push down
to initiate contact.

Before they pack up the raft,

They take stock
of the survival kit.

There's the first-aid package...

Miniflares...

Food rations...

A pocketknife...

And bags of water.

There are enough supplies
to keep you safe and fed

While you wait
for help to arrive.

Narrator: a braille typewriter
types raised dots

Using the braille system.

It's based on six dots
arranged in a rectangle,

Three dots high
by two dots across.

This is called the braille cell.

Different configurations of dots
within this cell

Represent different letters
of the alphabet,

Numbers,
and punctuation marks.

A braille typewriter
has a spacebar in the middle

And six keys, one for each dot
of the braille cell.

Pressing a key makes a pointed
steel rod, called a stylus,

Type a raised dot.

To build a braillewriter,

They first position
the six styli one by one

In a carriage
with steel spacers in between.

The spacers ensure
the styli move freely.

A cover plate seals
the back of the carriage,

And what's called a stripper
plate closes the top.

The plate has six holes

In the configuration
of the braille cell.

When you press a key,

The corresponding stylus
protrudes

And strikes the paper
against a dot-shaped eye,

Creating a raised dot.

They screw the die
to the carriage top

But don't install it
in the machine just yet.

This is how the carriage and die
will meet once it's in place.

They start connecting
the components

Which move the various styli.

The first part
is a steel cam rod.

One end of it has a little
eyelet called a lug.

They put a pin in it,
then slip that pin through holes

In the prongs of a metal strip
called a link.

Later, they'll connect
the other end of the link

To a lever attached to a key.

The braillewriter's
other components

Are made of cast aluminum.

The left end plate covers
the left side of the machine.

To that, they connect
the carriage tube,

The cylinder
on which the carriage rides,

And the feed roller,
the mechanism you turn

To feed a sheet of paper
into the typewriter,

Then what they call
the rear support,

An assembly
of cam rods and links.

They slide the carriage
onto the carriage tube.

Next, they install the drum.

The feed tube transfers
the paper to the drum.

The drum winds it
into the machine,

Positioning it for typing.

Then the rack bar.

Each tooth in it
is the width of a braille cell,

Ensuring the carriage advances

The correct distance
between letters.

Next, they install
the chain assembly,

Which advances the carriage.

They close off
the other side of the machine

With the right end plate.

Now they can finish the process

Of connecting the parts
that move the styli.

So far, each cam rod
connects to a link.

Now they connect each link
to a cam lever,

Then each lever to a key.

Here's how it all works.

You press a key...

It triggers the cam lever
to turn the cam rod...

And push up on the stylus.

The stylus strikes the paper

Against the die
yet to be installed,

Producing a raised dot.

There's still one more
paper-feed component

To install --
the pressure roller.

It holds the sheet of paper
against the feed tube.

Now they screw the die
to the carriage top

And install that
on a support beam.

Then they position this assembly

Over the stripper plate
at the top of the carriage.

They check and adjust
the paper hold tension.

The back plate has slots

For the two levers
that adjust the margins.

The apron goes below the keys,
the front plate above them.

Then the last component,
the carriage lever.

When you type
to the end of a line,

You push this lever to the left
to return to the left margin.

You also push a key
on the far left

To advance the paper
to the next line.

Typing on a braillewriter
is an embossing process,

So you have to use thick paper.

You push single keys
and combinations of keys

To produce different
configurations of dots,

Each signifying different
letters of the alphabet.

Narrator: this cello is
made of carbon fibers

Instead of traditional wood.

Enthusiasts believe
this newer carbon version

Has a more powerful sound
than the wooden instrument.

It still has
that characteristic sweetness,

But it's more likely to be heard
in the orchestral din.

And, after all, every musician
wants to be heard.

The carbon cello was the idea
of a boston symphony cellist

Who noticed waves
resonate loudly

Against carbon-fiber boats.

They cut the top piece
of the cello out of fabric

That's woven
with carbon strands.

This material is
stronger than steel,

Yet electric shears
easily cut through it.

A worker cuts out
numerous top cello pieces

And then sets them aside

While he works on another
section of the instrument.

He brushes special resin
onto a fiberglass mold

Of the cello's
back, ribs, and neck.

The mold has been prewaxed

To keep the resin
from sticking to it.

The idea is to saturate

This big piece of carbon fabric
with the resin

As he tucks it
into the curves of the mold.

He smoothes it down
to get rid of any bubbles

That could affect
the cello's tone.

He brushes more resin onto
the other side of the fabric,

Making sure
it gets into all the crevices.

He sponges away any surplus

And then layers
more fabric and resin

As he builds a laminated
carbon-fiber shape.

He covers the layers
with nylon-like material

And trims the edges
of the carbon fabric.

Next, he places
perforated plastic on the nylon

And piles absorbent batting
on top of that.

He installs a vacuum pump

And drapes a big plastic vacuum
bag over everything...

...then activates the vacuum.

It sucks out the air
and any excess resin.

The perforated plastic
controls the amount,

And the batting absorbs it.

While it's still under vacuum,

They put the whole thing
in an oven

To bake the carbon-fiber
layers together.

After they peel away
the batting and plastic,

It comes out looking like this.

The plies have fused together,

And the shell has
a sleek look to it.

They laminate the cello's
top piece in a mold

And bake it
until it's also hard.

Using a band saw,
they trim off the ragged edges

And sand them
for a smooth finish.

Now they clamp
the cello top piece

Onto a fixture that has
stencils on the back.

With a router,
they cut out the stencil shape.

The sound
will eventually emanate

From these f-holes,
as they're called.

They attach
the company's label with glue

To the inside of the cello's
back section.

Then they glue around
the top inner rim of the cello.

They tape the back tightly
in place while it hardens.

Next, they glue
the laminated carbon fingerboard

To the neck of the cello.

They drill holes into the pegbox

And insert the pegs which are
used to tighten the strings.

Soon, this cello will be
more than just a shell.

Coming up, we reveal
its inner workings.

Narrator: the story
of this cello has many layers.

They're all carbon,
and now the layers have hardened

Into the shape
of a concert instrument.

At this point, you can't make
music with it, though,

Because they have yet to
construct the inner workings,

A process that is
another demonstration

Of fine craftsmanship.

The cello frames
need a bit of bodywork.

They rough them up
with sandpaper...

Then spray on
a polyurethane clear coat

To protect the surface.

Then it's over to the string
specialist, called a luthier.

He sets a roughly cut wooden
bridge on top of the cello

And takes measure
of the position.

The placement of this bridge
needs to be exact

Because its job is
to elevate the strings

And transfer their vibrations
to the instrument.

If its position is a bit off,

The cello's sound
will also be a bit off.

Using a grease pencil,

He maps out the position
of the bridge

Between the f-holes,

Then sets it aside.

Now he slips the wooden sound
post into one of the f-holes

And wedges it between the front
and back of the cello.

The sound post is crucial.

It will strengthen the cello

And couple
the strings' vibrations

Between the front and back
of the instrument.

This is delicate
and highly skilled work.

He measures to determine if
the sound post is on the mark.

If it's off by even a fraction
of an inch,

He adjusts it a bit more.

Afterwards, he double-checks
the bridge's positioning.

Then, with a red grease pencil,
he colors over the spots

Where the feet of the bridge
are to sit.

He presses the bridge's feet
into the grease marks,

And this makes red smears
on the feet.

The smears tell him
where to shave the wood

So that it will fit perfectly
on the top of the cello.

The bridge
doesn't get glued down.

It's held in place only by
the pressure of the strings.

Next, he makes pencil marks

On both tips
of a measuring stick.

He leans the stick
against the bridge

At the same angle as the strings
that will run over it.

He then transfers
the pencil marks

From the stick
to the top of the bridge.

He rounds off the marks by
penciling around a template.

And then he carves the bridge
down to size.

He planes it down
to make it thinner.

With a file, he cuts grooves
to cradle the strings.

Now he moves to the bottom
of the instrument

And slides a spike called
an end pin into a precut hole.

The end pin will rest
on the floor,

Steadying the cello.

He lassos the end pin
with plastic rope,

Which is attached
to the tailpiece,

And he rests the tailpiece
on the belly of the cello.

He pulls the steel strings
from the pegs

And hooks them
onto the tailpiece.

Like most classical
string instruments,

The cello has four strings.

Now he slides the strings
into the grooves on the bridge.

He turns the pegs
to tighten the strings.

The strings push down
on the bridge,

Holding it in place.

He tunes the cello,

And now it's ready
for a real performance.

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