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--Captions by vitac-- www.Vitac.Com

captions paid for by discovery communications, inc.

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

Nails and staples --

a fascinating manufacturing process.

Safety glasses --

focused on protecting your eyesight.

Fabrics --

we'll weave our way through a textile mill.

And bicycles --

we gear up to see how they're made.

If you've ever needed to attach two pieces of wood,

you know there's no shortage of fasteners.

You can choose from common nails, spiral nails,

finishing nails, and even staples.

And if you've ever wondered

where these useful little items come from,

well, we've got it all nailed down for you.

There are hundreds of varieties of nails being made,

and they're made of very durable carbon steel,

all starting from steel wire.

Rolled up on a drum,

this steel wire weighs in at 5,500 pounds.

The wire's diameter is a quarter of an inch.

And that's too large,

so they'll have to reduce its size.

Using many drums,

they're going to pull the wire successively

to gradually thin it.

Then they'll roll it up again.

When full, this roll will contain

almost 80,000 feet of wire weighing 2,500 pounds.

The wire now has a diameter of 1/10 of an inch,

so it will have to be reduced by half.

Now they're going to cut the wire into little rods.

The cut rods are gathered up with this electromagnet

and dumped into a machine that will process them.

Here, the rods are made into nails.

The metal rods move along slowly,

and a blade forms the nail points.

These blades are changed every 600 hours.

This machine forms nailheads

by flattening them with great pressure on the rod ends.

Nailheads are formed at a rate of 1,400 per minute.

The manufacturing of nails is now finished.

They fall into a chute, then into this collecting bin.

Nails are sold by the pound

or embedded in plastic rolls, as we see here.

This machine inserts 167 nails into each roll.

The plastic strip has teeth, and the nails hook into these.

They handle the rolls with gloves,

since the coating applied to the nails is not yet dry.

This machine produces five rolls a minute

for a total of 835 nails.

Making spiral nails requires an extra processing step.

This machine puts the spirals into the nails

with these cylinders and welds them.

It makes 1,200 nails a minute.

Then the nails are put together into strips

for use in pneumatic nailing guns.

Each strip contains 30 spiral nails.

To help them in place, the nails are coated

with a resin that dries in four minutes.

This is the nailing device that uses nails on a strip.

It sets the nails in one strike with the user's trigger finger.

Now we move on to the fabrication of staples.

The staple press binds 80 iron wires,

which have been well-lined up.

The 80 small wires are placed side by side.

The wires are glued together.

Then the wires come out well-adhered to one another.

The staple strips are fed into this machine.

It cuts the staples to the desired length

and folds them in one stroke of this press,

which applies 40 tons of pressure.

Staples are formed on this gauge,

and the staple strips are then ready for packaging.

Every day they produce a total of some 25 million nails here,

which require the processing

of 11,000 tons of metal annually.

Narrator: At work and at play,

our precious vision can be at risk.

For instance, we need to protect our eyes

when we're using power tools and when we're playing squash.

Thankfully, all we need to do is wear safety glasses.

How do they make them so resistant?

Let's have a look.

Many sports and trades require the wearing of safety glasses.

These glasses are made with plastic molding.

Here we see the interior of a mold.

The optical part of the lens is mirrored

in order to be as transparent as possible without being deformed.

The glasses are made by melting the primary material,

a plastic resin called polycarbonate.

The resin granules are poured into this machine.

It becomes liquefied at a temperature of 450 degrees.

The liquid plastic is injected into the mold under pressure

over a 30- to 60-second period.

The plastic hardens rapidly,

and the glasses are then removed from the mold.

They mold several glasses at a time.

The glasses are separated by hand

and then are given an initial visual inspection.

The glasses are placed on this support.

They're then taken to the laboratory,

where they'll be given a surface treatment.

But before beginning the treatment,

they're washed to eliminate any impurities

and to assure that the coating treatment

adheres well to the lens.

When they've been washed,

the glasses are then rinsed in clear water.

The glasses are now gently soaked in a chemical solution,

which prevents misting and scratching of the lens.

This coating now has to be cooked.

They direct the glasses toward an oven

heated to 480 degrees.

The soaking and cooking processes

vary between 30 minutes and 2 hours.

Each pair of glasses is inspected to make sure

there are no imperfections or distortions in the lenses.

Then the glasses are placed on this support.

This milling machine automatically removes

the last piece of polycarbonate.

This one was left in place

so that they would be able to handle the glasses

without having to touch the lenses.

At this stage of the production of the glasses,

the nosepiece is glued on.

Certain pairs of glasses are selected

from each production run.

Here they evaluate the resistance of glasses

to a racquetball hurled at them at 90 miles per hour.

Here a hockey visor is tested

against a puck traveling at 60 miles an hour.

To conform to safety standards,

the glasses must withstand these tests.

It confirms that they're truly safe.

They now proceed to final assembly steps

in making the glasses.

The last few pieces of the glasses,

such as the plastic ear stems, are installed.

Now completed, the glasses are placed in cases.

It's the final step in their fabrication.

They make several types of safety glasses here --

industrial, hockey and football visors,

swimming goggles, and racquetball glasses.

This facility turns out

thousands of safety glasses every day,

and the polycarbonate resin used to make those safety glasses

could very well save your eyes one day.

Narrator: Early man relied on animal skins

to protect himself against the elements.

Eventually, fabrics were invented,

giving us a bit more choice in the matter

and eliminating the need to hunt or go naked.

Today textile mills make fabrics

in every conceivable pattern and color.

Fabric is made from thousands of braided threads.

This mill has 700 bobbins of polyester.

Each bobbin contains 155 miles of thread.

We begin by separating the threads.

This warp unit takes the 700 strands and assembles them.

Then this comb separates them.

Other strands are added,

and in total there will be 7,000 of them.

One fabric is composed of threads braided at 90 degrees.

The warp threads are assembled lengthwise,

while the weft threads are joined transversely.

To prevent the threads from tearing,

they pass through a bin of glue.

These rollers eliminate the surplus.

The glue will be removed with water before dyeing the threads.

The glued-together threads exit this machine.

These large green cylinders are heated

and dry the glue on the threads.

Knitting will soon begin.

The 700 strands are newly separated on this loom roller.

Each thread must pass through a blade

to produce a specific design.

This machine takes the 7,000 strands of thread, one by one,

and they pass through the blade.

It's a highly precise operation.

The threads pass through a blade,

and the weaving finally begins.

On this jacquard-type loom roller,

the warped thread is inserted by a jet of air.

The weaving machine assembles two loom rollers

made of 7,000 strands.

The fabric reaches a width of 12 feet.

The dark threads are inserted into the weave.

They insert 600 weft strands per minute.

The blades remove the weft strands

to insert the warp ones between the two.

A comb pushes the weft.

The plate of the breakage chain stops the machine

if a thread should break.

This bobbin contains 155 miles of thread.

The weft thread is in the insertion nozzle.

When a weft is inserted, an air jet nudges it in.

The loom roller operates at full tilt.

It makes 600 thread intersections a minute.

Weaving is now over.

We move on to the following steps -- washing and dyeing.

Washing is done in a soapy solution at 175 degrees

and at a speed of 195 feet of fabric a minute.

The fabric is rinsed in clear water of about 85 degrees.

Now it's on to dyeing.

This is done with jets.

Up to 7 1/2 miles of fabric is placed in clean water

into which colorants have been added.

The solution is heated,

and the fabric soaks here for about six hours.

Then it will be rinsed in lukewarm water.

The fabric is placed in a bin.

This machine is called an opener.

It unfolds and stretches the material

before rolling it up on an immense roller.

And now the roll is almost full.

We now move to thermosetting in a high-temperature oven

that dries the fabric.

The temperature is almost 400 degrees

at the oven's entrance.

The fabric circulates here for 45 seconds.

The bobbin that we saw at the beginning

has produced 15 miles of fabric.

This finished roll weighs 3,300 pounds.

Narrator: Bicycles have come a long way

from the original basic design.

Now they feature multiple gears,

high-tech materials like carbon-fiber frames

and featherlight metal alloys.

And they're made to tackle everything

from quiet bike paths to the most rugged mountain trails.

A French invention of 1790,

the first bicycle resembled a 2-wheeled wooden horse

without pedals or handlebars.

In 1817, a German gave it direction control.

The addition of pedals to the front wheels

came from France in 1861.

The British contributed as well,

adding the large front wheel in 1870.

By 1903, all countries participated

in the first bicycle Tour de France.

A bicycle is a beautiful piece of engineering.

The frames are made of steel

or a chromium-molybdenum alloy known as chromoly.

Fabrication begins with these hollow tubes.

The tube cutter cuts the steel before sending it to the bender.

The bender curves the tubes cold,

exerting strong pressure against the bending jig.

The tubes must now be machined --

that is, cut into lengths

so that they correctly fit into one another.

During this operation, cutting oil cools the tube.

The tube is cut, taking into consideration

the insertion angle of the other pieces.

Tubes to be welded together are placed in this support.

They insert a piece in an alloy of silver and bronze,

which increases the strength

and produces a better finish at the welding point.

Welding now takes place.

Welding of the frame requires about two minutes

at a temperature of over 1,400 degrees.

Once welded, the part takes four minutes to cool.

They proceed in the same way with all the tubes

that form the frame of the bicycle.

At this stage, it's important to straighten the frame,

which could have deformed during welding.

They verify the alignment of the tubes

and straighten it out cold

with a tool that sets it to the right dimensions.

Now they're going to paint the frames.

Paint is applied with a spray gun

and adheres to the frame by static contact.

Then the paint will be baked

in a natural-gas oven at 425 degrees for 15 minutes.

The frame is now cooled, and we can begin the assembly.

The labels are now applied.

In another department,

an employee assembles the handlebars.

He installs the mechanism for the brakes and the gears.

Now we move on to the wheel rims.

The 36 stainless-steel spokes of each aluminum wheel

are installed manually.

The dexterity of these workers allows them to install spokes

on 65 wheel rims in an hour.

This spoke tool allows them to screw the spokes into the rim.

This machine exerts a pressure on the spokes

so that they'll have the desired tension.

If there's too much or not enough tension,

the rim will be crooked.

This machine aligns the rims,

essential for proper functioning of the bicycle.

It automatically adjusts the spokes

so that the wheel will be truly straight.

Next step --

placing of the tubes and the tires on the wheel rims.

Set upside down,

the bicycle circulates from one workshop to another,

where they will install the last mechanical parts.

These accessories are not made here.

The handlebars, the pedals, the fork, the brake,

and chain mechanisms are all installed manually.

Here they screw on the rear brake plate.

Finally they inspect each bicycle

to make sure that the bolts are well-tightened

and that everything's working properly.

Then it's on to packaging.

This factory makes 2,500 bicycles each day.

Assembled from various tubes of chromoly,

each one weighs about 25 pounds

and will run for thousands of miles.

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