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Article: The diameter of a beard is 0.1mm, the thickness of a razor is 0.08mm. The science of shaving

ヒゲの直径は0.1mm、カミソリの薄さは0.08mm。髭剃りの科学

The diameter of a beard is 0.1mm, the thickness of a razor is 0.08mm. The science of shaving

About Beard

There are two types of beard hair: coarse hair and vellus hair.
Between the terminal hairs are distributed very fine vellus hairs with a diameter of about 0.01 mm, which are poorly pigmented. The diameter of the vellus hairs is 0.1 to 0.23 mm. A hard, scaly outer layer (cuticle) surrounds the soft, pigmented fur. The center of the fur is a central axis called the medulla. Vellus hairs are almost the same as terminal hairs, except that they lack a medulla. An adult male's face has 6,000 to 25,000 terminal hairs that are round or oval in shape. The speed at which beard hair grows varies considerably from person to person and from place to place, but beard hairs grow at an average speed of about 0.4 mm per 24 hours and are as hard as a copper wire.

Also, the distribution of whiskers is not uniform.

The sparsest area is on the underside of the cheeks (18-36cm2) and the thickest above the upper lip (75-110cm2). In general, hair grows at an angle of 30-60 degrees from the skin surface. Most hairs are associated with sebaceous glands and are covered with oils secreted by them.
An important property of hair is that it becomes flexible when wet. Wet hair is 1/2 to 1/3 of its strength compared to dry hair, which is a factor that affects the comfortable shave that extends the life of your razor blade.
Therefore, preparing the skin before shaving is an important element of shaving, and if you do the right thing, such as removing the oil that covers the surface of the hair and promoting water penetration to soften the hair, you can enjoy a comfortable shave.

Beard seen under a microscope

I used a microscope to look at things that are smaller than a millimeter and cannot be seen with the naked eye. First, beards. Even if you think you've shaved properly, there are still some areas that you haven't shaved properly...

Freshly shaved (clean skin surface)
In some places, the hair roots remain, but are no longer protruding from the skin. However, they are barely visible to the naked eye.

After 12 hours (You can see the cross-section of the hairs)
This is the condition when I shaved in the morning and checked in the afternoon. A little bit of beard has grown. You can see it with the naked eye.

After 14 days (You can see that the beard is longer and the ends have been cut with a sharp blade)
After 2 weeks of growth. You can clearly see the cross section of the hair tips.

[Reference] These are the bristles of an Italian-made brush sold at Kazori Club. They are made from natural badger hair. When you place the shaving brush on your skin, the bristles penetrate into the pores and thoroughly scrape away dirt.

About the Skin

Cross section of skin

The skin is not smooth and its elasticity varies from place to place. The skin is made up of two layers, a thin epidermis and a thick dermis underneath, and the hair roots are located in the dermis. The epidermis is further divided into several layers. The stratum corneum is made up of dead cells that are constantly being shed, and wet shaving is extremely effective at removing these dead cells. Analysis of shaving shaving reveals roughly the same amount of skin debris as hair.
New cells grow from below the epidermis and reach the surface of the skin in about 10 to 20 days, so the skin we see is less than 20 days old.

Results of growing a beard for 4 days without shaving and then shaving it

Shaving with a razor removes the dead skin cells as well as the facial hair, revealing new, fresh skin.
The skin is never smooth and its elasticity varies from place to place.
The skin is made up of two layers: a thin epidermis and a thick dermis underneath, and hair roots are located within the dermis.

The epidermis is further divided into several layers: The stratum corneum is made up of dead cells that are constantly being shed, and wet shaving is extremely effective at removing these dead cells.

Analysis of the shavings revealed hair and mostly skin flakes from the victim.
New cells grow from below and reach the surface of the skin in about 10 to 20 days.
Therefore, the skin we see can be said to be that of an animal less than 20 days old.
After shaving, using an aftershave lotion or lotion will help keep your skin smooth.

After shaving

Why does your beard look blue in the evening?

Even if you shave in the morning, by the evening a thin layer of beard will grow back and it will tend to look blue. So why does your beard look blue?
This is due to the pigment in their body hair. For Japanese people, it looks bluish, but for people from other countries, it can be brown or even black.

It is said that beards grow most quickly between 6am and 10am.
On average, people who work shave between 6:30 and 7:30 in the morning, and their beard starts to grow again after that. Even if you shave thoroughly in the morning, your beard will turn blue by the evening because of the principles of human nature.

In other countries, the thin beard that grows in the evening is called the "5 o'clock Shadow," which literally means "the shadow from 5 o'clock."
If you are having trouble with your skin turning blue, it may be a good idea to shave properly in the afternoon or use an electric shaver as a simple treatment before the evening.

A razor blade is 0.08mm thick

How thick is the tip of a razor? When we looked at the stainless steel tips of razors from well-known manufacturers, we found that double-edged and twin-edged razors were standard at 0.08 to 0.1 mm thick, injectors were 0.5 mm thick, and even the thickest single-edged razors were only about 1.3 mm thick.

The edge of the blade that comes into contact with the beard is incredibly thin, measuring just 1/100,000 of a millimeter, and it is said that if you stacked 750 of these blade edges together, they would be just as thick as a newspaper.

A lot of research has also been done on the angle of the cutting edge.

For example, let's say you attach a 20-degree blade to a 0.1mm thick stainless steel plate. The length of the blade surface will be 0.28mm. The average diameter of a Japanese person's beard is said to be 0.08mm, so if you try to shave with a blade surface that is 0.28mm long, the blade surface will be more than three times the diameter of the beard, which will increase the friction width and dull the cutting performance.

To improve sharpness, the length of the blade is adjusted so that it corresponds to the diameter of the hair. The angle of the blade tip and the length of the blade tip differ depending on the manufacturer, but the standard angle is about 16 to 24 degrees, and the length of the blade tip is about 1/4 of the diameter of the hair, or 0.02 mm.

The cutting edge is also made up of three surfaces, and the grinding angles of coarse grinding, fine grinding, and fine grinding (cutting edge) from the top make it a sharp and durable edge. The cutting edge is coated with a layer of hard metal called spackling to make it even more durable, and a polymer coating is welded to it to reduce friction between the blade and beard when shaving, resulting in a soft shave and long cutting time at the same time.

The above document was published in 1995, and current replacement blades are much thinner, with some manufacturers even coating the blades.

Recently, the latest 4- and 5-blade razors have become popular, and replacement blades with cleaning mechanisms to remove shaving debris and smoothers to make the cut even smoother are also available.
The tip of the replacement blade has also become thinner in pursuit of even sharper cutting ability, and the unit of measurement for the thickness is angstroms!
From the pursuit of a close shave to the many blades, replacement blades are designed to provide a gentle shave on the skin.

Even the seemingly ordinary razor blade has been designed and crafted with great care.

Weight is important when it comes to razor holders

We often hear from guests that they got razor burn when using the razors provided at the hotel. This is not due to a bad razor blade, but rather to the weight of the razor holder.

If you use a holder that is appropriately heavy, the weight of the entire razor will shave off your beard, so no more pressure than necessary will be placed on your skin.

On the other hand, with a light holder, it is not the weight of the holder that causes the force transmitted to the holder by the hand, but rather the pressure applied to the skin more than necessary. Because the hand is not stable, you may unknowingly remove more skin than necessary along with the facial hair.
When using a light holder, try to apply as little pressure as possible to avoid razor burn and achieve a comfortable finish. Also, we do not recommend shaving against the skin for those with sensitive skin.

A blog where I grow a beard every day and observe the changes to my face!

I'm going to try growing my beard for a month while staying at home. From April 30, 2021 (Updated daily)

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