2014/2015 Session Metal Work

Scheme of Work SS2 First Term WEEKTOPIC 1Definition Pattern 2Method of Pattern Development 3Types of Pattern 4Methods of Laying out of Pattern

PATTERN DEVELOPMENT Definition: A layout of a complete surface of an object is called its pattern, girth Or stretch-out. In technical drawing it is called its development. Patterns are used in Industries to produce containers, machines etc made of sheet metal and plate metal Method Of Pattern Development: These include: a.Parallel line method b.Radial line method c.Triangulation Method Parallel line method involves the use of parallel lines to produce the stretch-out. This method is used for producing geometrical shapes like cylinders and prisms. Radial line method involves the use of arcs/radial lines. It is used for geometrical shapes taper to the apex like cones and pyramids. Triangulation method involves dividing the surface into triangles; the true sizes of the triangle found and are drawn in order – side by side to get the pattern produced. This method is used for complex geometrical shapes.

Method of Laying Out Pattern: This refers to the way of transferring patterns from the paper to the given metal surfaces. There are two methods, viz: i.By drawing the pattern on the article/object on paper, place carbon paper underneath and place both on the metal and trace the drawing. ii.By directly producing the pattern on the metal. Assignment 1.Define pattern 2.List and explain the methods of pattern development 3.Explain the “methods of laying out patterns” and list these methods.