design and technology st aidan’s high A pictorial sketch of a wall lamp is shown. The shade is in the form of a cut cone. Draw, from the given Elevation of the shade: The Plan of the shade projected from the Elevation (7 marks) The Development of the shade (7 marks) DA 14 marks O O GC Credit Paper – 2003 – Question 5

design and technology st aidan’s high Drawing the Plan and Finding the Generators Start by drawing a circle to show the base of the Plan uncut. Divide the circle using a 30 o /60 o set square and number each of the points. O O Draw generator lines from the base to the apex of the cone. Project each of the 12 points down onto the base of the Elevation and number each of the points found. (1)(2)9(10)(11)(12)

design and technology st aidan’s high Finding the Cut Points on the Plan For points 6 and 12, project a horizontal line through the point in the elevation until it cuts the outside edge of the cone. Project this point up to the centre line on the Plan. Draw a part circle through this point to find the required points on the Plan for points 6 and 12. O O Project from the Elevation to the Plan the positions of all of the points where the angled cut along the bottom cuts each generator. Mark each point found on the Plan with a small dot (1)(2)9(10)(11)(12)

design and technology st aidan’s high Completing the Plan O O The curve on the Plan showing the cut bottom surface can now be drawn. A circle can also be added for the top cut on the cone. Because this cut is horizontal the Plan shape will be circular and can be drawn with compasses. The Plan is now finished and can be darkened in (1)(2)9(10)(11)(12)

design and technology st aidan’s high Starting the Development O Start drawing the Development by drawing a vertical line through point ‘O’. Using the sizes of the 12 areas from the Plan mark off 12 steps round the base line of the Development to find the positions of the generators, and join these points to the apex Number each of the generators drawn. Draw a curve with a radius the same size as the length of the side of the full size cone. O (1)(2)9(10)(11)(12)

design and technology st aidan’s high Finding the Cut on the Development O To find the positions of the cut points on the Development it is necessary to transfer all of the points from the Elevation onto a True Length line. O Use compasses to measure each length down the True Length line and transfer these to the Development. Draw a smooth line through each of these points (1)(2)9(10)(11)(12)

design and technology st aidan’s high Completing the Development O The top cut on the Development can be drawn as a part circle, measured again down the True Length edge of the cone. O Add the seam edges to the drawing to complete the view. The final Development can now be darkened in (1)(2)9(10)(11)(12)

design and technology st aidan’s high O O The finished drawing should look like this (1)(2)9(10)(11)(12)