the blade rotates about the point of rotation. A proper amount of tension should be present, for safety reasons, to ensure that the blade does not spin freely when opening or closing. Construction Straight razors consist of a blade sharpened on one edge and a handle attached to the blade through a pin. The blade can then rotate in and out of the handle. The blade can be made of either stainless steel, which is resistant to rust but can be more difficult to hone, or high-carbon steel, which is much easier to hone, obtains a sharper edge but will rust more easily than stainless steel if neglected. Cheap stainless steel straight razors from Asia and more expensive stainless steel and carbon steel razors from Europe are available. A razor blade starts as a shape called the blank supplied by the steel manufacturer. Forging The blank of the blade is produced by forging steel ingots or steel available in other forms such as wire, springs, etc.. After the blank is formed, the first step is to clean it using a heavy forge. The material used for open razors is steel with a minimum carbon content of 0.6%. This percentage of carbon content ensures optimum hardness, flexibility and resistance to wear. Following the forging stage, a hole is drilled in the tang at the pivot point. This is a crucial step, since after the steel hardening process it would be impossible to drill. This process requires great skill. Hardening and tempering The steel is hardened through a special process where the forged steel blade is heated up to approximately dependent on the specific steel. This heating enables fast and uniform heating of the steel at the optimum temperature for maximum hardness. The tempering stage follows the hardening process, where the blade is heated in a bath of oil at a temperature between . Tempering imparts the steel its flexibility and toughness according to the phase diagrams for steel. There are three types of steel blade according to the level of tempering it has received. Hard-tempered, medium-tempered and soft-tempered. Hard-tempered edges last longer but sharpening them is difficult. The converse is true for soft-tempered blades. The characteristics of medium-tempered blades are in-between the two extremes. Carbon steel blades can reach a maximum hardness of 61 HRC on the Rockwell scale. Grinding Following the processes of hardening and tempering, the blanks are ground,