RAZOR. The ordinary razor is an instrument used for shaving and consists of a hardened steel blade, made with an extremely fine sharp edge and fitted into a handle.
The early razor of modern times was made of steel which had a wedge-shaped section, with straight sides tapering to a sharp edge, and although simple in form it was a good and durable in strument for its purpose. Early in the last century, the practise was introduced of hollowing out the sides of the blade by grind ing, to facilitate sharpening the blade, and improve fineness of the cutting edge. At first the degree of hollowness, or concavity of the sides. of the blade was small, but with great skill, hollow-grinding has been carried considerably further, increasing the lightness and flexibility of the blade. The full hollow blade is thinner in the cen tre than nearer the cutting edge. Hollow-grinding is performed by using grinding wheels of successively diminishing diameters. The processes of the production of the blade consist of :—forging under the hammer, marking with name of maker, drilling the hole for the pin, then hardening and tempering of the blade; grinding and hollowing ; glazing and buffing on small leather-covered wheels with polishing material. The blade is then etched, fitted with handle, whetted to a fine sharp edge. Etching is sometimes very elaborate.
Safety Razor.—The razor is naturally considered a dangerous instrument, and many attempts have been made to make it safe. Not until the introduction of the "Gillette" type of razor, at the beginning of this century, was a satisfactory solution found. The principle of the "safety" razor is to place a guard between skin and cutting edge of the razor blade, so that the guard permits the edge to pass over the uneven surface of the part to be shaved, removing the hair without cutting the skin.
In some cases devices are provided to enable the user to strop or re-sharpen the blades. The quality of the steel strip sup
plied by the steel-maker for use as blades in the safety-razor, is the result of a combination of the highest grade of skill and experience on the part of the steel-maker and the rolling-mill engineer.
Cutting edges of the blade are formed by whetting on suitable wheels.
Other types of safety devices are based on the desire to re tain the general form of the ordinary razor, while rendering it safe in use. These take the form of fitting a suitable guard to the blade of the ordinary razor, or the substitution of a holder, carrying an adjustable blade of the strip-steel type.
Electric Razor.—With the invention of the Schick Dry Shaver by the late Lieutenant Colonel Jacob Schick, U.S.A., retired, an entirely new technique was introduced to the art of shaving. This dry shaver consists of a shearing head mounted on a powerful little motor encased in a handle made of some suitable substance, such as bakelite. The shearing head includes an outer and an inner member—the outer member having a very thin shear plate with openings or slots in it to rest against the skin, while the inner member has teeth which co-operate with the nether edges of the walls of the shear plate slots or openings in a shearing action. The toothed inner member is held up tightly against the inside surface of the shear plate by means of springs or other appropriate means and is made to reciprocate very rapidly underneath the shear plate by the motor at approximately 7,200 times a minute. The hairs of the face which penetrate the openings or slots in the shear plate are thus sheared off by the reciprocating motion of the inner member in co-operation with the nether edges of the slot walls of the stationary shear plate.
The electric dry shaver operates without the use of sharp blades, soaps, brushes, creams and lotions.