Carbon steel razor:

This is the traditional razor, that is to say a simple mixture with iron and carbon (1 percent), which enters into the composition of the steel. This sharpens razor very well and offers a perfect cut, his only fault is its vulnerability to air and water: oxidation. That is why it will always wipe after shaving and keep in a dry place and protected from wet air stream, see if oil remains without use or if you are traveling in countries with high moisture and heat.

 

Stainless steel:

Appeared at the beginning of the last century this type of razor was especially favored in hospitals by surgeons (steel also known as "surgical" as 440). This type of steel is oxidized much less because of its composition-chromium steel which makes it vulnerable to moisture months and air and therefore requires less care. The only disadvantage is that this razor has to be more difficult to sharpen, but with a thread which is longer.

 

Sizes: why?

 They are expressed mostly in inches and fractions comprise as 5/8, 6/8, 7/8, which corresponds to the value of one inch divided by the prime number for Example 5/8 that of ( 2.54 / 8) * 5 or 1.8 cm, which determines the width of the blade. Other measures such as Inch (English) and is divided into number of size 9, 10, 11, 12, 13, 14 as is the case for razor FILARMONICA this measure in inches and corrspond is also 2 , 54 cm per unit and is divided into 16 to razors or for a number of 14 FILARMONICA calculation to obtain the blade width in centimeters: (2.54 / 16) * 14 is a figure of 2.24 corresponding to a blade type 7/8.

Blades of small size can be 1/8 as a Boy Eicker I have and go to 3/8 their use is the hairdresser and are called "razor blades or thinning" for the haircut and not beard.

From size 4/8 razors these cater to the size of the beard, beard fine for this model and for all beards for sizes 5/8, Standart size the most widespread.

Sizes 6/8 and 7/8 are intended mainly for people with stiff beard, the razor type 8/8 are rare and very hard for beards.

 

 

Why do these razors they cut through the same?

The back of blade tip shape and angle. This angle is more closed (low) over the edge is thin and therefore smooth cutting. According to this idea, so we could get back to razors fine and widths very small but practical matter, you could the strop without turning the thread ... ! because the tool would be too small for your hands! So there is a standard for the tool is adapted to handling required for its sharpening and cutting!
The hair is weaker, softer than cotton and requires a sharp too pronounced, and therefore the size of 3/8 very suitable for cutting, while a beard instead show more resistance, and the razor blade too thick will not cut the hair properly!

Hardness of the hair: razor parade size / hardness of the steel.

So from what we have seen we have a more razor size, the higher the fine will be sharp for shaving beards hard. However there is another parade and is an adjunct or replace it, providing the toughest steels therefore can bear to be more finely worked again. For indeed, which will limit the sharpness of the edge is also its material: steel harder may refine, sharpen thinner than its opposite. Therefore the steel is more hard it is refinable, resulting in more cutting is soft. These treatment processes are: the double hammer, double tempering, cryogenic treatment, the addition of other mineral element making stronger steel.

 The old blades are what we call "knife barber" because the hollowing of these blades was low (Wedge on the sketch).

Why do different hollows?

From the mid 19th century, the straight razor suffered a major development with the production of slide steel fragment  which material is removed to make them lighter and more manageable.
There are several types grinding:
Full blade (wedge), not hollow
blade slightly hollow (quarter hollow)
half-hollow blade
completely hollow blade (full hollow)
Consequences on the beard are not trivial: a very hollow razor is generally more fragile and less durable than a half-hollow razor, so we often favored for people with strong beards using half-hollow razor.
Only progress in the manufacture of hard steels somewhat change the way, and now thanks to these steels the major part of the razors are fully hollow ground and can respond to all beards.
Grinding work is lengthy and costly. The price of these blades on the market depends if you choose, quarter, half, full holllow or singing razor !