All language subtitles for S08E13 - Manhole Covers; Range Hoods; Artificial Logs; Snowmobiles (576p AMZN WEB-DL x265 Garshasp)_track4_[eng]

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Narrator:
Today on "How it's made"...

Manhole covers....

...Range hoods...

...Artificial logs...

...And snowmobiles.

Manhole covers
Are those metal lids

On maintenance holes
And roadways.

Workers lift them to enter
And repair sewers

And other underground utilities.

Foundries make the covers
Out of heavy-duty cast iron

So they last for decades

And don't budge
Under passing traffic.

This company makes
Hundreds of models

Of manhole covers and collars,

The rims upon which
The covers sit.

They come in two types
Of cast-iron alloy --

Either ductile iron, which
Has magnesium to reinforce it,

Or gray iron, which is heavier
But just as strong.

To make a cover,
They first have to make a mold.

This one's got the design of the
Cover's top side carved into it.

Workers pour in
About 650 pounds of sand

Mixed with glue and a hardener.

For the underset of the cover,

They repeat the step
In another mold.

A worker creates a channel
In the sand mold

Through which they'll pour
The molten metal.

He plugs the hole
With a wooden block

To preserve the cavity beneath.

He removes the block
And briefly reinserts the pipe

To ensure the cavity
Hasn't caved in.

It takes about 15 minutes
For the sand mix to harden.

A machine then inverts each box

And vibrates
To shake out the mold.

To make one manhole cover,

Workers will join molds
Of the top and bottom sections.

Alignment lugs
And glue between the sections

Help them align properly

And form an airtight seal
So molten metal won't leak out.

Next, the machine
Flips the bottom mold,

Moves the top mold
Into position below,

Then mates the pair.

The factory buys scrap metal
From demolition sites

And also recycles its own.

It'll melt these metals
With certain minerals

To enhance the mix.

Graphite to make it malleable,

Silicon to make it stronger,
And magnesium

To make this batch of ductile
Iron lightweight yet strong.

Here, a giant magnet

Picks up chunks of recycled iron
And steel.

The metal is preheated
To 780 degrees fahrenheit

Then transferred to a furnace.

There, at 2,700 degrees
Fahrenheit,

It takes about a half hour
To melt enough metal

To make 35 covers.

Workers then transfer
The molten metal to a cauldron

And add more silicon.

This evens out the consistency
So it's easier to pour.

Besides the channel
For pouring in the metal,

Some larger molds
Have vent holes

To evacuate burning gasses.

It takes
About an hour and a half

For the metal to harden.

A conveyor then drops the molds
Into a container

And breaks them open.

Using a hook,
They pick up the casting.

This one's a collar
Weighing about 220 pounds.

They knock off the remaining
Bits of sand

And excess bits of metal
That formed during the casting.

These scraps get recycled
Into a new batch of iron.

Manhole covers vary in size

According to
The specifications ordered.

Most are roughly the diameter
Of a car tire.

The average weight
Is about 140 pounds.

A worker now smoothes out
The edges of the collar,

And then the perimeter
Of the cover.

This way, it will sit flush
On the collar.

This machine tests
The strength of the cover

By applying pressure.

It must withstand the weight
Of a car on every one-inch area.

They paint the covers
And collars

By dipping them
In a bath of black tar.

Once dry, the pieces
Have a rust-resistant finish

That lasts for decades.

And the buyers
Expect them to last,

Because a manhole cover
And collar cost up to $1,400.

Narrator: people have cooked
On stovetops for centuries,

But it wasn't until about 1800

That metal stoves with flues
Vented steam and smoke outdoors.

Today, factories
Make encased fans

That powerfully ventilate
And also light the stovetop.

A stovetop
Is often called a "Range,"

Hence the name "Range hoods."

No matter how well you cook,
Steam and smoke are inevitable.

Fortunately,
The range hood's fan,

Called the blower,
Clears the air in seconds.

Production begins with
This computer-guided machine.

It cuts out
A sheet of galvanized steel

To make part
Of the hood's housing.

A 300-ton press
Then perforates the sheet

And cuts out up to 50 openings

For screws, wiring,
And exhaust outlets.

A worker inserts another panel
For the housing

In a 25-ton press.

The machine bends the steel
In two places.

They'll use this component
To make a circular channel

That evacuates smoke and steam

That often contain
Grease particles.

To curl the panel,

The worker uses another machine
With three rollers.

It forms the circular channel

That fits around the blower to
Direct air through the exhaust.

Here a spot-welding machine

Joins two corners
Of the hood's housing.

This is mainly for aesthetics.

A weld looks better
Than a screw or bolt.

This 80-ton press
Bends the hood's shell,

Making one of 80 folds that give
The component its final shape.

Now a worker
Removes the plastic coating

That protected the steel
During the cutting.

He applies a sticker
With a product I.D. Code.

Then a pad printing machine
Marks the brand name,

1 of 12 this factory produces.

This is the first of eight stops
On an assembly line.

A worker installs a transformer

To power the blower's motor
And two halogen lights.

This circuit board
Regulates several functions,

Including
Three light intensities

And the blower's
Four-speed motor.

She attaches the board to
The housing with three screws.

This panel has lights that
Indicate what functions are on.

Next, the worker installs

The blower's
165-watt electric motor.

The motor attaches
With three screws

Into rubber bushings
That reduce noise...

Then, light sockets made
Of heat-resistant plastic.

The blower's housing snaps
Into place around the motor.

A little silicone on the housing

Ensures an airtight seal
Around the blower.

Then she installs
The blower wheel.

Next, she plugs
The lights in to test them.

You press this button
Three times

To make the lights
Increasingly bright.

There's one button
For each of the motor's speeds.

After snapping a panel on
To enclose the hood assembly,

A worker attaches a plastic ring

To direct air
Through the blower.

A computer system
Tracks each model's assembly.

When workers complete a step,
They input it into the system.

An optical scanner

Also senses when they remove
A part from 1 of 25 cubbies,

Like these removable air filters
Made of mesh aluminum.

The tracking system's
Called "Polka yoke,"

A japanese-inspired method
That insures thorough assembly.

It follows each model

Until workers place it
In a box for shipping.

The system's final task
Is to ensure

That they put in
The mail-in guarantee card

And the installation manual.

If workers forget anything,

The system reminds them
With a loud buzzer.

Once they staple the box closed,

A machine with suction cups
Picks it up

And stacks it
10 boxes per pallet.

All this work
So you can stay in the kitchen

Even if you can't stand
The heat.

Narrator:
In the mood to light a cozy fire

In your wood stove or fireplace?

No need to put on
Your coat and boots

And trudge through the snow
To the outdoor wood pile.

Nowadays you can buy
A box of manmade logs.

A lot less hassle for you,
Fewer trees die,

And the environmentally
Friendly brands pollute less

And are safer for your chimney.

These artificial logs are made
Entirely of compressed sawdust.

Their moisture content
Is less than 9%,

Compared to 30%
In real firewood.

The compression
And dryness combine

To make these manmade logs
Easier to light than real ones.

They don't throw sparks
While burning,

And they produce 300% more heat
Than real firewood.

The high temperature
Burns up the gasses better,

So the logs emit
Up to 50% fewer pollutants,

And they produce fewer ashes
And far less creosote,

A highly flammable tar

That's a natural byproduct
Of wood burning.

Creosote buildup in a flu
Can cause a chimney fire.

The sawdust comes from pure,
Natural hardwood,

Mostly oak and maple.

The log company
Buys it from factories

That make hardwood flooring.

So from the start,
These logs are ecological

Because they're made
Of recycled waste.

The sawdust is clean,

And the log factory
Doesn't add chemicals,

So it's safe
To cook over the fire.

The sawdust moisture content
Is so low

Because the wood it came from
Was already dried in huge ovens

To make the flooring.

The sawdust arrives
In different consistencies,

So the first step
Is to put it through a grinder

To make the particles
Uniform in size.

The next step is the key one --
Compression.

At a rate of 5,500 pounds
Per hour,

An air-blowing system moves
The sawdust from the grinder

Directly into
A compression machine.

The machine is a giant cylinder
With a piston that moves inside.

The piston
Compresses the sawdust

Using extreme high pressure --
6,000 pounds per square inch.

The result is a 40-foot-long
Compressed sawdust log.

Unlike some other brands
Of artificial logs,

This one contains
No binding agents

Which can pollute the air.

So how does the sawdust
Stick together, then?

The secret
Is the high compression.

The intense heat it creates

Bonds the natural resins
In the sawdust.

As the log exits
The compression machine,

A cutter shapes a flat edge.

This is a safety feature.

With a flat edge on the bottom,
The logs are easier to stack

In the recommended
Three-log configuration,

And they don't roll
Out of position.

Now, a guillotine
Chops the 40-foot log

Into 40 smaller logs,
Each 1 foot long.

A separator pulls them apart.

The company also produces
A 10-inch log.

The logs drop
Onto a conveyor belt

That leads to
The packaging area.

The factory boxes its logs

With instructions
And two fire starters.

The starters are made
Of sawdust and candle wax,

More effective than using
Newspaper to get the fire going.

This competitor's artificial log
Breaks easily

Because it isn't as dense.

This company's log,
On the other hand,

Is more solid because
It's so tightly compressed.

That high density translates
Into more burning time.

Three logs will keep
Your fireplace alight

For about three hours.

Narrator: for centuries,
Inventors tackled this challenge

With determination
And frustration.

The first snow machines

Trudged through winters
Awkwardly and slowly.

But by the late 1950s,

New technologies
And materials emerged

To make snowmobiles that could
Blaze through the snow

With increasing ease
And comfort.

Snowmobilers often face
Rugged terrain.

Snowmobiles
Need a rock-solid build

To keep the rider
Safe and comfortable.

It all begins
With an aluminum-alloy frame.

The pieces arrive partly
Assembled to the radiator.

The robot spins
And positions the frame.

A computer-guided frame-rivet
Machine punches holes

And inserts rivets directly into
The frame with great precision.

This process bonds the parts
Tightly so they can't vibrate.

Next comes the rear suspension,

Aimed at making the ride
As smooth as possible.

Inserting this plastic slide
Onto the runner

Minimizes friction between
The track and the suspension.

A conveyor belt carries
The suspension system

Through several stations.

Wheels and sprockets will turn
The track that grips the snow.

The suspension kit
With springs and coils

Goes directly into the runners.

Along with
These shock absorbers,

The suspension will fit snugly
Into the snowmobile's frame.

Workers tighten everything
Manually for now.

Later, a machine
Will tighten things even more.

Assembling
The transmission system

Starts
With this countershaft.

First, they install
A high-performance brake disc

Made of forged steel.

The chain case
Fits snugly on top

Thanks to the ridges
On this ring.

This die-cast aluminum casing

Will house two gears
And a chain.

This bolt connects to a spring

That keeps the gears
And chain tight as they turn.

The chain-tightener

Must slide smoothly
Back and forth in its groove

To keep
The chain's tension even.

This test checks that the spring
Expands and compresses properly.

Now comes the oil gauge.

It's essential that oil
Lubricate the parts thoroughly

Because the motor will generate
A lot of friction.

The transmission
Fits on top of the frame.

These coils, springs,
Runners, and wheels fit easily

Into the rubber track.

The rear suspension system
Connects to the track system

While this
White plastic sprocket

Connects the track
To the transmission.

The speed sensor attaches
Directly to the sprocket.

Four high-grade steel bolts

Anchor the rear suspension
System to the frame.

They're so strong

That the suspension
Can withstand the vibrations

That come with high speeds.

Now for the engine assembly.

Bolts attach the electric
Starter directly to the engine.

The fuel-injected engine
Generates a lot of heat --

Up to 1,300 degrees fahrenheit.

This shield has layers
Of insulating wool

That act as a heat barrier
To protect the driver

From scorching-hot exhaust.

The engine's
Made of cast aluminum

So it's relatively light --
Just 100 pounds --

And it propels the snowmobile
Up to 120 miles an hour.

Now for the front
Of the snowmobile.

This front suspension system

Requires a different assembly
From the rear one.

A hoist brings it all together.

The gas tank is made of
Lightweight molded plastic

Rather than metal.

The throttle controls the speed

Just like a gas pedal in a car.

They install
The throttle assembly,

And a few more
Functional details.

These lightweight,
Aerodynamic plastic side panels

Give this snowmobile
A sleek look.

And now, the final step.

The zero-gravity hoist
Lifts it all onto a skid.

Polystyrene sheets
Protect the snowmobile

During transport
To the retailer.

From start to finish,
It's taken three hours

To assemble this showroom-ready,
Snow-travelling machine.

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