PATTERNS

                 In casting, a pattern is a replica of the object to be cast, used to prepare the cavity into which molten material will be poured during the casting process. Patterns used in sand casting may be made of wood, metal, plastics or other materials. Patterns are made to exacting standards of construction, so that they can last for a reasonable length of time, according to the quality grade of the pattern being built, and so that they will repeatably provide a dimensionally acceptable casting. Under certain circumstances an original item may be adapted to be used as a pattern. The making of patterns, called pattern making (sometimes styled pattern-making or pattern making), is a skilled trade that is related to the trades of tool and die making and mold making, but also often incorporates elements of fine woodworking. Pattern makers (sometimes styled pattern-makers or pattern makers) learn their skills through apprenticeships and trade schools over many years of experience. Although an engineer may help to design the pattern, it is usually a pattern maker who executes the design.