30x06 - Spiral Stairs; Pita Bread; Exhaust Headers; Molded Limestone Artwork

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Narrator: spiral stairs
were part of a strategy

To defend the towers
of medieval castles.

Attackers had to
climb single-file

And couldn't storm
the castle all at once.

And at the top of the stairs,

The guardsmen could more easily
maneuver their swords,

Giving them the upper hand.

Spiral stairs take people
to the next level

Without taking up
a lot of space.

They're compact, and with
their corkscrew curvature,

They can also be
architectural features.

Production starts with
the steel hubs

Cut to the desired riser height.

A worker files
the sharp edges smooth

And drills a threaded hole

Which will be used to fasten
the treads in place.

A computer-driven plasma system
cuts through a sheet of steel

To produce the pie-shaped
stair treads.

A worker nestles a tread
to the hub

And clamps them
in a weld fixture.

He also clamps
structural supports

To the base of the tread.

With everything in
the right configuration,

He welds the supports
to the tread and the hub.

He'll make 12 of these hub
and tread assemblies.

He chips off the weld slag
for cleaner seams.

A team slides the hub
and tread assemblies

On to the center pole

And rotates them
to the correct position.

The design geometry
dictates the rotation.

Once rotated correctly,

The workers fasten the hubs
to the pole

And add a platform
for the top step.

A baluster spins in a lathe,
as tools cut it to length

And round the end
to the correct diameter.

The operator measures
the diameter.

He inserts the rounded end
in a dye

That carves the thread into it.

A worker welds a steel cup

Just above the threaded part
of the baluster.

This cup will support
the baluster

Once it's been installed
on the thread.

He grinds the weld scale
from the cup.

He inserts the baluster
through holes

In a metal spacer in the tread.

He screws a nut on to the end
to secure it.

Using rollers now, another
worker twists long strips

Of metal into spiraling
hand rails that match

The rise of the stairs.

He fits the rail
to the top balusters

And clamps it in place.

He then welds the balusters
to the rail.

He adds more railing until
it spirals all the way down

To the first step.

The team secures it
to the platform.

The spiral staircase's metal
structure is now complete.

It's ready for
the wooden accents.

A worker applies glue
to pieces of red oak.

He'll use two of them
to make one stair tread.

He clamps two tread sets in
a fixture while the glue sets.

He inserts a shim

And tightens the clamp
to apply downward pressure.

Once the glue has cured,
a planer shaves the tread

Perfectly flat
and to the desired thickness.

After refining the profile,

A worker rounds the edge of
the stair tread using a router.

After gluing strips of wood
together to create

A curved railing,
he sands the excess adhesive,

And with a file,
removes more of the glue.

He turns the railing over
and carves a groove in the wood.

This will enable the railing
to be installed

Over the metal rail support.

He adds some detailing
along the edge.

A team then fits
the wooden railing

To the metal support structure.

All of the rail sections
fit together perfectly.

After the pre-fit,
they remove the railing

And sculpt the edges
to be rounder.

The rounded edges complement
the overall spiral design.

A worker pre-fits the wooden
treads to the metal structure

And then disassembles
the entire spiral staircase

For painting and staining.

The spiral stairs are then ready
for reassembly in the building

They were designed for.

They'll definitely add a certain
twist to the interior design.

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Narrator:
originating in the middle east,

Pita bread has been around
for thousands of years.

Today, its popularity continues
to grow around the globe.

Part of its appeal
is its versatility.

People can stuff
their pita's pockets,

Use it as a sandwich wrap,
or slice it for dipping.

Pita bread may be flat,

But that doesn't mean
it's boring.

Anyone can use pita
to make any number

Of interesting
lunchtime combinations.

Making pita bread starts
with silos full of flour.

A blower system delivers the
flour to an automated sifter.

The sifter shakes the flour
through three levels of mesh

To filter out impurities.

Magnets extract
any metal contaminants.

Workers prepare a pre-mix
of sugar, salt, yeast,

And preservatives.

They combine these ingredients
with the sifted flour

In a big mixer and add water.

The mixer is equipped
with numerous bars

That rotate horizontally
to blend the ingredients.

The operator opens the mixer
and spins it one more time

To eject the dough into a bin.

He rolls the bin
to the next station.

Here the pita dough
goes into a hopper.

And from there,
it drops into a machine

Called a dough divider.

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This machine turns big chunks
of dough into many small blobs.

To do this, it forces the dough
through a round hole,

And a guillotine blade chops it
to the correct thickness.

The dough blobs ride a conveyor
and pass under a roller

That flattens them.

Flour from an overhead sifter
dusts the dough blobs

To keep them from sticking
to the machinery.

Each one of these flattened
dough blobs

Will eventually become a pita.

The round pieces of dough
now ride

A conveyor up to a warm zone.

Over a period of 15 minutes,
the yeast ferments,

Causing the dough to rise.

Out of the fermentation station,

A roller flattens
the pita dough segments again.

They're now ready
to be rolled very thin

In a process known as sheeting.

The next roller presses
the pita dough much thinner.

Rolling it in one direction

Makes the dough segments
oval-shaped.

The oval pitas ride by a pusher

That now shoves them
towards the final roller.

It rolls the dough in the other
direction to round out the shape

And make it even thinner.

Perfectly round and thin,

The pitas now travel up to
another fermentation operation.

Inside, the temperature
is toasty.

It's warm enough to reawaken
the yeast

And cause the dough
to rise again.

Conveyors move in criss-cross
directions to take the pitas

Back and forth.

This zig-zagging journey
lasts about 15 minutes.

When the pitas emerge
from the chamber,

They have thickened up
substantially.

They head into an oven
where the magic happens.

The oven's temperature is
between 750

And 930 degrees fahrenheit.

They spend just


This flash-baking causes
the water in the dough

To turn to steam.

The steam puffs the pitas,
creating pockets inside.

The pitas then travel

On conveyors
for a 20 minute cool down.

As they cool, they deflate.

The process has created pockets
in the pitas.

Once sliced open,

The pockets can be stuffed
to create sandwiches.

Workers stack the pitas
six high for packaging.

The next conveyor delivers
the stacks into the clutch

Of an automated arm.

Just ahead, a burst of air
opens a bag

And the arm inserts
the pitas into it.

At the same time, it pushes
the bag on to the next conveyor.

Moving forward, another device
automatically twists

The open end of the bag.

The device applies
a plastic lock tab

To the twisted end of the bag,
sealing the pita breads inside.

The bags pass by
a metal detector,

And then they're on their way
to the supermarket.

This pita bread has taken


But it should enable lunch
to come together very quickly.

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Narrator:
installing exhaust headers

Will add extra power
from a car's engine.

They bolt on to the engine,
giving each cylinder

Its own exhaust pipe
leading to the collector,

Which connects to the car's
main exhaust pipe.

That's more efficient than
having all the cylinders exhaust

Into a common manifold.

A header draws out significantly
more spent exhaust gasses

After combustion, leaving room
for a greater amount

Of new gas and fresh air

To enter the cylinder
for the next combustion cycle.

Headers are made of steel
or stainless steel.

A worker uses a roll cutter
to slice tubes into nearly


For the header's collector.

A forming tool on a press

Stretches one side
of the collector outward.

Then the worker places the same
side on an end-forming machine,

Which shapes it like
a four-leaf clover.

He slips a flange over
the unshaped side

And widens that side to create
the ball portion

Of the gasketless ball
and socket connection

To the car's main exhaust pipe.

Meanwhile, another worker
roll cuts narrower tubes

Into 32-inch-long pieces to make
the header's primary tubes,

The ones that attach at the top
to engine's cylinders.

A worker slides a tube
on to a mandrel,

Then the computer-guided
mandrel bender

Bends the tube in four places.

The mandrel fills the inside
of the tube

Just up to the bend point,
preventing the tube from

Compressing or collapsing
under pressure.

The header they're making here
is for a four-cylinder engine,

So it has four primary tubes.

An eight-cylinder engine
requires a pair of headers,

Whereas a six-cylinder engine

Requires a pair
of three-tube headers.

A worker trims the bent
primary tubes

To the required length
with a bandsaw.

The sawed edges of the tube
are ragged,

So the next step
is to grind them smooth.

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After grinding, the edge
no longer looks like this.

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Workers heat the top end
of the tube

With a torch
to soften the steel.

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They place the end
into an end-forming machine.

The machine shapes the end

To match the top profile
of the cylinder,

To which the tube
will be mounted.

Cylinder profiles vary
from engine to engine,

So workers simply change
the forming tool on the machine.

A worker clamps the header
flange with its four

Exhaust ports on to
an assembly jig and positions

The top end of
a primary tube in each port.

He inserts the bottom ends

Into the four-leaf-clover-shaped
collector.

He then welds the top end
of each tube

To its exhaust port
on the header flange.

Then he welds a tag
with the company name

On to one of the tubes.

Finally, he welds
the bottom end of the tubes

To the collector.

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The header's three sections --
flange, tubes,

And collector -- are now fused.

The worker grinds down the weld
around the ports

Until it's nearly flush.

The remaining bit of weld
material encircling the port

Will act
as a seal to prevent leakage.

During the welding,
some welding material drips

Into the header flange's
openings,

So a worker reams
the bolt holes with a drill

And grinds
the edges of each port.

He mounts the header on
the corresponding engine's

Cylinder head to make sure bolt
holes are sufficiently cleared.

Then he runs a torch over all
the joints to check the welds.

The flame would sh**t through
any hole in a weld,

Alerting them to repair it.

This factory applies one of two
finishes on its exhaust headers.

The basic one is a coat
of black water-based paint

Sprayed on and air-dried.

It prevents surface rust
from forming

While the part is warehoused.

The higher-end finish is an
aerospace-grade ceramic coating,

Available in black or silver.

This baked-on finish protects
the headers from rust

For many years
of high-performance driving.

♪♪

Narrator:
this may look like ivory,

But it's actually limestone.

It looks as though
it's a sculpted work of art,

But it's actually molded.

How does one mold limestone?


In france figured out how,

And their descendents are still
molding limestone artwork today.

This unique art form exists
because, two centuries ago,

A family in france discovered
springs amid volcanic rock,

Springs with water so rich
in calcium carbonate

That it petrified into stone.

That is limestone.

The family carved out caves,
then invented a way

To capture the calcium carbonate
and mold sculptures with it.

The descendents of the family
continue that tradition today.

The springwater contains
two grams of calcium carbonate

Per liter and a lot
of iron oxide,

Which makes the water orange.

The original troughs
direct the water

On to a bed of wood shavings.

The shavings trap
the iron oxide,

And the calcium carbonate floats
to the surface.

In the workshop,
the owner of the company --

The seventh generation
of the founding family --

Makes the mold.

He heats something called
gutta-percha

In a pot of water
to soften it up.

Gutta-percha is a natural latex

Made from the sap
of the gutta tree.

Once it's soft, he weighs out
the required amount

Using the workshop's
original scale.

Then he kneads it to force out
trapped air

And make it more malleable.

After forming it into a ball,
he places it in an old press

Made my his great-grandfather.

The press shapes
the gutta-percha

Into a rectangle measuring


After cooling in the press
for 30 minutes,

The gutta-percha has hardened

Just enough to maintain
the rectangular shape.

He removes it from the press

And places a silicone-designed
template on top.

He cuts the gutta-percha
to the shape of the template.

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He places the gutta-percha
on top of a pattern

Created by an artist.

He places the template
on the gutta-percha,

Then a plank of wood
on top of that.

He puts the entire assembly
under an old screw press.

An hour later, he removes
the assembly from the press

And gently separates the layers.

The artwork design is now
transferred from the pattern

To the gutta-percha.

He sets it aside to cool
to a hard state.

When the work of art
is either too wide or high

To fit into
the traditional screw press,

The artisan then sculpts
the pattern out of clay.

Once the clay hardens, he coats
it in silicone to make the mold.

This modern mold-making
technique is a bit trickier

Because silicone
can't be reheated

And reworked like gutta-percha.

The silicone takes about


To harden into a flexible mold.

A silicone mold can be used
only once.

And because it's so flexible,
it has to sit on a support tray

So that it doesn't buckle
when filled or moved.

Now it's time to mold
the limestone.

A craftsman positions
the molds under these

Liquid limestone waterfalls.

The carbonic gas in the liquid
gradually evaporates,

Leaving accumulating deposits of
calcium carbonate in the molds.

An artisan moves every mold
to a new position daily

So that the dripping water
hits all parts of it.

Artwork just one 1/5 of an inch
thick requires

Six months under the fountain.

Artwork 4/5 of an inch thick
requires two years.

To extract the limestone artwork
from a traditional mold,

The artisan immerses it
in hot water

To soften the gutta-percha so
that he can gently peel it off.

Every intricate detail
of the design

In the gutta-percha
is now replicated in limestone.

This molded rock is as strong
and hard as marble.

To extra the artwork
from a silicone mold,

An artisan removes the support
tray and lifts off the silicone.

The company has more than 500
artwork patterns in stock

Dating back to 1821.

Not all the molded limestone
looks the same.

The artisans can tailor
the shade from white to ivory

By controlling
how much iron oxide

They remove from the water.