24x03 - Upright Pianos, Flags, Wet/Dry Vacuums, Medieval Axes

[bunniefuu]

Narrator: unlike a grand piano,
an upright piano is vertical,

So you can place it
against a wall.

Uprights come
in various heights.

The taller ones have longer
strings and a larger soundboard,

So their sound is closer to that
of a grand piano.

Around four feet tall,

This is the largest upright
piano on the market.

It's designed for those
who lack the budget or space

Of a grand piano.

A piano technician

Spends several days calibrating
the pre-assembled action stack.

It has 88 wooden hammers
with heads wrapped in felt.

Pressing a piano key

Causes the corresponding hammer
to strike a particular string.

The string vibrates, producing
a specific musical note.

A damper stops the string
vibration a split second later,

Ending the sound.

Each key has two slots
called mortises.

They are lined
with a felt bushing

To protect the wood from wear.

At the back of each key,

There's a height adjustment rod
called a capstan.

Each key has an embedded lead
disc.

This disc equalizes the pressure

That's needed
to play an individual key.

Without this pressure
equalization,

You would have
to press harder on the bass keys

Because their hammers and

Strings are heavier.

The soundboard is already
installed in the piano cabinet

Under a cast iron frame.

The technician checks

The clearance
between soundboard components.

He verifies
that each steel string

Is properly wound
to a tuning pin at the top,

Loops over a hitch pin
at the bottom,

And passes over a wooden bridge
in between.

After making
necessary adjustments,

He measures the pressure
of each string over the bridge,

A critical factor
producing fine tone.

Then he tunes below the bridge,

Adjusting string tension
as needed.

[ Notes play ]

The technician
assembles the keyboard

By aligning each key
with corresponding pins

On the key frame.

He uses round spacers called
punchings to equalize height

So the black and white keys
are level.

He checks the tightness
of each key's bushings.

If a key needs to be loosened,

He compresses the bushing
and widens the mortise.

Then he installs
the action stack

Directly above the keyboard,

Attaching it to bolts
mounted on the cast iron frame.

He presses each key a few times

To make sure
it functions properly.

If it doesn't,

He adjusts the capstan
to better strike the key.

Then he connects the pedals
to the components they control.

The right pedal

Pulls the dampers
away from the strings

To let the sound continue.

The left pedal draws the hammers
closer to the strings,

Which reduces the volume
of the sound.

Then several more
calibrations --

Each hammer
to make sure it moves correct,

Each backcheck

So that it doesn't rebound
and strike again.

And finally, each key

Is checked to ensure
that the pressing depth

Is identical
across the keyboard.

If a key needs adjustment,

He adds or removes punchings.

They come in a range

Of thicknesses from heavy felt
to ultra-thin tissue paper.

He plays with different
combinations until the pressing

Depth is perfect.

[ Note plays ]

Now he strikes a tuning fork
to sound an "a"

And tunes
the corresponding "a" key.

Then he tunes all the other keys
in relation to that note,

Tweaking each tuning pin
with a special wrench.

[ Chord plays ]

An assembler completes the piano

By mounting the remaining
sections of the cabinet.

This cabinet is made
of wood and laminates,

Coated in high-gloss
polyester resin --

An elegant yet simple exterior,

Enclosing very complex
internal workings.

Flags bring strangers together
to support a cause or a nation.

For many centuries, a flag
fluttering above the fighting

Was a visible
communication signal.

Flags eventually
became patriotic symbols

Away from the b*ttlefield.

And today there is one for every
country and almost every cause.

Flags bring strangers together
to support a cause or a nation.

Rippling in the breeze,

Flags have a kinetic energy
that draws people to them.

At this factory, they make flags
from special polyester.

It's extra strong,

But it's also translucent
to make the design

Visible from both sides.

A machine unwinds the fabric

Over rollers
that pull it straight and tight.

It then enters
a digital printer.

The first printing head
lays down the image

And a second one deepens it.

Printing in two steps
keeps the dyes from running.

The employee
transfers the printed fabric

To the next machine.

He loops it through guide
rollers and secures the end.

The flag material travels

Over a larger cylinder
that's heated to 419 degrees.

This bakes or fixates the dye
into the fabric.

At the wash line,

A worker aligns the flag
with a sheet of leader fabric

And trims the end.

A sewing machine
stitches the fabrics together

In a chain lock configuration.

This seam is tough enough

To withstand a series
of wash cycles.

The first wash
removes any excess dye

That wasn't fixated
on the fabric.

They add special chemicals
to this wash

Because ordinary soap
isn't strong enough.

The second bath
contains chemicals

That neutralize
the cleaning substances.

Finally, the fabric
travels through a rinse station

To remove
the residual chemicals.

Pressurized rollers
wring out the water.

The damp fabric travels
over steamed heated cylinders

That dry and iron the fabric.

The flag material
winds around rollers

Before reaching
the cutting table.

The worker first cuts out

The color code printed
on the side of the fabric.

She uses a spectrometer

To confirm
that the colors are correct

And haven't faded
during the wash.

Then she cuts out the flags

Using a pair
of industrial scissors.

The polyester material is strong

And doesn't unravel or fray
during the cutting.

The next worker stitches
a sleeve onto the fabric

For the banner hardware.

She also hems
the other three sides.

At another station, a machine
installs a grommet on the front

And a washer on the back
to make an eyelet.

An employee inserts
a fiberglass rod in the sleeve

And threads a bungee cord
through the eyelet.

He inspects the fit

And confirms that the flag
will withstand strong winds.

From conception to completion,

It takes about three days
to manufacture flags.

Then the sky's the limit.

Narrator: you can use a wet/dry
vacuum both inside and out,

To clean up messes

That an ordinary cleaner
can't handle.

This powerful picker-upper
can suction everything

From leaves
to small pieces of wood,

And if you remove the filter bag
from the tank,

It can vacuum liquids, too.

A wet/dry vacuum is lightweight,

Yet can handle
heavy-duty pickups

That would ruin
an ordinary vacuum cleaner.

Most of the components
are plastic.

This machine produces them

By sh**ting molten plastic
into molds,

Then cooling it
to a solid state.

A robot
extracts the finished parts.

All the vacuum's parts

Are injection-molded
except for the electric motor.

The motor has two fans.

One cools the motor itself
with ambient air

And the other creates a vacuum
to suck debris through the hose.

The vacuum fan
is in a separate chamber

So that liquid never
comes in contact

With the motor's
electrical components.

Workers place the motor
in a plastic housing

With the drive shaft
facing upward.

They put a spacer on the shaft,

Then mount the vacuum fan,
securing it with a nut.

They close up the housing
with a grid plate.

This prevents fingers from
accidentally touching the fan.

They now take the head assembly
to a testing area.

They'll run the motor
for up to 10 minutes

To make sure everything
functions correctly.

Then they plug it
into a second test station,

Which verifies
that there's adequate suction

And no electrical
short circuits.

If everything checks out,

They send the head assembly
to the packaging area.

There, workers assemble
the rest of the vacuum.

At the first station,

A press locks the inlet securely

In a hole
at the front of the tank.

At the next stop, a worker
places a package of screws,

An instruction manual,
and four casters

To be installed by the purchaser
in the tank.

Next, workers
take the head assembly

And add it
to the vac's top cover.

They load the vacuum's lid

Onto a carousel along
with a pleated paper filter.

The filter prevents dust
and fine debris

From getting
into the vacuum fan chamber.

Then they mount
the head assembly

On an automated
screw-driving machine

And place the lid on top

After first removing
the filter.

Once the lid is screwed
to the head assembly,

They put the filter back on.

Now they place the assembled lid
onto the tank...

...and snap down the latches
to secure it.

The final stop on the line

Checks the suction power,
the electrical system,

And makes sure the on/off switch
works correctly.

If the vacuum passes testing,

A robot picks up the unit
and places it in a retail box.

Workers add extension wands,
a nozzle, and a hose,

Then finally a filter bag
is added,

Which is only used
when vacuuming up dry debris.

Consumer wet/dry vacs
come in several tank sizes,

From 1 to 24 gallons.

Narrator: during the medieval
era, axes were more than tools.

They were terrifying weapons

That could inflict
very deep wounds.

Today, craftsmen
still make battle axes

For use
in the entertainment industry.

The medieval battle ax
was a brutal weapon.

With a single blow,

It could break through
a knight's armor

And fatally wound him.

To produce an authentic replica
for movies and tv shows,

The blacksmith consults
reference books.

He sketches the ax head design
on paper,

Roughing out the details
to the desired scale.

He cleans up pieces
of old carbon steel,

Which he'll combine
with other metals.

In total, there will be 75 metal
strips of varying composition.

To complete the mix of metals,

He cuts an old blade
made of nickel steel alloy

Into equally sized strips.

He loads 37 strips into a vice.

He tightens the vice
and tack-welds them together.

He sands the welded stack.

He rubs oil into the stack
to prevent oxidation.

Now, exposed to intense heat,
the metal layers forge together.

He spreads a mix of borax
and other minerals called flux

Onto the surface.

This deters oxidation

As the forging continues
with a pneumatic hammer.

The hammer slams the layers

Together to become
a solid laminated block.

It's ready to be transformed
into the ax's cutting head.

Repeated strikes pinch the metal
in the center.

He sprinkles the flux mixture

Onto the surface of
the metal form, heats it again,

And folds it into a "c" shape.

After a reheat,

He inserts a layer
of carbon steel in the center

For the blade.

He hammers the "c" shape flat,

Leaving the pinched section
round for the handle.

The 75 strips
have been forged into one.

Next, the power hammer
refines the handle knob.

He drives a steel stake
called a tapered drift

Into the center of the knob.

This forms an opening
for inserting the wood handle.

Using the power hammer,

He now flattens the blade end
of the ax head substantially.

He flares it
to form a cutting edge

And removes the excess
with a plasma cutter.

He saws it off,

And the result is fierce.

The ax head has taken shape,

But it needs some refining.

He hammers the handle area
to spread it wider.

And dips the ax head in water
to cool it down.

Then he grinds the blade thinner
using a belt sander

And rinses off the residue.

He grinds it again
to get rid of any hammer marks

Or oxidative scale.

The different metals
react when dipped in acid,

Creating a swirled pattern
on the surface of the head.

The first bath was contaminated,
so he polishes it off

And gives the ax head
another rinse in clean acid.

After heat treating
and tempering,

He polishes the face of the ax
and hones the edge.

Next, he grinds spiral grooves

Into a piece of oak
for the ax's handle.

A colleague stains

The entire handle
to accentuate the carved spirals

And enhance the grain
of the wood.

Once it dries,

The blacksmith wedges the ax
head onto the handle.

A few strikes against
a steel block improves the fit.

Finally, he hammers upholstery
studs onto the handle

To simulate the rivets

That reinforced the original
medieval ax handles.

This medieval ax
is ready for action.

Medieval ax replicas

Are authentic props
for any tv show or movie.

Handled carefully,
no one will get hurt.

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