Razor



A razor is a bladed tool primarily used in shaving on the body to remove unwanted hair.

Early razors
Razors have been identified from many Bronze Age cultures. These were made of bronze or obsidian and were generally oval in shape, with a small tang protruding from one of the short ends.

Straight razors
Straight razors with open steel blades were the most commonly used razors before the 20th century. However, they are now chiefly used by barbers.

Straight razors consist of a blade sharpened on one edge. The blade can be made of either high-carbon steel, which is slow to hone and strop but dulls more slowly, or stainless steel, which hones and strops quickly and resists rusting, but requires more frequent sharpening. At present, stainless-steel razors are easy to find but expensive; carbon-steel razors are even more expensive and difficult to find though they are available from several cutlery companies, notably older German firms.

The blade rotates on a pin through its tang between two protective pieces called scales: when folded into the scales, the blade is protected from accidental damage, and the user is protected from accidental injury. Handle scales are made of various materials, including mother-of-pearl, celluloid, bone, plastic and wood. They were once made of ivory, but this has been discontinued, though fossil ivory is still used occasionally.



Safety razors
The first safety razor, a razor where the skin is protected from all but the very edge of the blade, was invented in the late 18th Century by a Frenchman, Jean-Jacques Perret, who was inspired by the joiner's plane. Marketed as "the best available shaving method on the market that won’t cut a user, like straight steel razors."

The first American safety razor was marketed in 1875 by the Kampfe Brothers. In 1901, the American inventor King Camp Gillette, with the assistance of William Nickerson, invented a safety razor with disposable blades. Gillette realized that a profit could be made by selling a razor with inexpensive disposable blades. This has been called the Razor and blades business model, or a "loss leader", and has become a very common practice for a wide variety of products.

There are also safety razors that are made of inexpensive materials that are meant to be wholly disposable.

Electric razors
The electric razor (also known as the electric dry shaver) has a rotating or oscillating blade. The electric razor does not require the use of shaving cream, soap, or water. The razor is powered by a small DC motor, and usually has rechargeable batteries, though early ones were powered directly by house current. Some very early mechanical shavers had no electric motor and had to be powered by hand, for example by pulling a cord to drive a flywheel.

The typical major designs include the foil variety which uses a structure of layered metal bands that partially pull out the hair before cutting off the extracted length and then allowing the remainder to retract below the skin. The other design is the rotary type with circular blade structures, usually three in a triangular arrangement which has the same shaving function.

It was patented in 1928 by the American manufacturer Col. Jacob Schick. The Remington Rand Corporation developed the electric razor further, first producing the Remington brand of razor in 1937. Another important inventor was Prof. Alexandre Horowitz, from Philips Laboratories in the Netherlands, who invented the very successful concept of the revolving electric razor. It has a shaving head consisting of cutters that cut off the hair entering the head of the razor at skin level.

Early versions of electric razors were meant to be used on dry skin only. More recent electric razors have been designed to allow for shaving cream and moisture. Some patience is necessary when starting to use a razor of this type, as the skin usually takes some time to adjust to the way that the electric razor lifts and cuts the hairs. This also requires diligence in the use of moistures.

Electric-Razor Batteries
Early electric razors plugged directly into an AC outlet, but in recent decades most have been rechargeable, containing rechargeable batteries sealed inside the razor's case. Most manufacturers have been reluctant to divulge the chemical nature of the batteries, but one can infer from the instructions—"discharge fully, then recharge overnight"—that they use nickel cadmium batteries. Curiously, the batteries cannot be removed without using a screwdriver and a soldering iron (or wirecutters), and doing so voids the warranty; nor can one buy new batteries from the manufacturer. This differs from the practice of cell phone makers, who advertise the type of batteries and sell replacement batteries, which are easily removable without tools. Even some cordless phones have user-replaceable batteries of known composition.

In theory, one can return the razor to the "dealer" for repair, but most stores that sell such devices—and even the manufacturers—lack repair facilities. In practice, a device that fails within a month can be exchanged for a new one under the store's guarantee; or a device that fails after the store guarantee expires but before the manufacturer's warranty expires can be exchanged by the manufacturer—the store guarantee and the manufacturer's warranty are mutually exclusive. If it fails after the warranty expires, one is expected to throw it away and buy a new one, from the same company. There used to be repair shops that offered warranty service for such devices, but in the 1980's, most became mail-forwarding services that sent things to manufacturers for replacement; and most disappeared in the 1990's.

Some modern styles of electric hair clippers include bulk hair clippers, which are used to remove a bulk of the hair being shaved; main hair clippers, on which guards are attached to achieve a perfect length all over the head; and mini clippers, which are used to trim the edges of the haircut.

Other razors
A single-edge razor blade was actually manufactured prior to the advent of the double edge razor, for various applications where the blade is required to be hand-held. Single-edge blades are often a more rigid steel and much thicker, as well as being less sharp (but with much sharper non-rounded corners). They are used in carpentry for detailed work, sanding, and scraping (in a specialized holder), in mechanical drawing for paper cutting, in plumbing and finish work for grouting and cleaning, for removing paint from flat surfaces such as panes of glass, and in many other applications. Razors are also sometimes used in bread production to slash the surface of an unbaked loaf; in this usage, they are referred to using the French word lamé.