Sheet metal is often used in the design of electronics products. It makes a great choice for enclosures, brackets, and many other components due to its formability.  Punching and bending sheet metal is a very economical manufacturing process relative to machining, die casting, etc.  It is an inexpensive media with many beneficial properties including thermal and electrical conductivity.  On the surface electrical conductivity may not sound desirable for an electronic product, however it is essential in the containment of electro-magnetic radiation.

Selection of sheet metal thickness is often based on structural strength.  There are standard material thicknesses for sheet metal typically referred to as ‘gauge’ in the United States.  Sheet metal gauges for steel are based on its weight.  Aluminum and other materials have different thicknesses for the same gauge (ie. 16ga steel is .0598″ thick while 16ga aluminum is .0508″ thick).  Rumor has it, the guy that established these gauges is the same guy that decided a yard will be 3 feet, a foot being 12 inches, and a portion of an inch being quoted as any fraction which has a denominator that is some power of 2.