What is the Metal Hardness Scale?

There are many ways to test a metal's hardness — each test comes with its own corresponding scale.  Three common methods are: (1) Turner-sclerometer (or just sclerometer), (2) Shore-scleroscope (or just scleroscope), and (3) the Brinell method.  The tests vary in what type of object is used against the metal to be tested and how that object is applied to the metal.  The sclerometer test, for example scratches a pointed diamond forwards and backwards across the metal, while the Brinell method presses a steel ball into the metal.  Depending on the severity of the resulting impression, the metal is given a score based on a predetermined scale.  The sclerometer scale, for example, ranges from 1 (for lead) to over 100 for hardened steel, whereas the Brinell method ranges from 6 (for lead) to over 550 (for hardened steel).