usb dvd-downloadtool fr windows 7 chip

through by the section plane, completes the elevation required. Again Problem 43. Let Fig. 132 be the plan of a hollow square pyramid, its height being twice tJie length of a side of its base, and a sectional elevation of it on the line SP be required. As the cutting plane passes through the axis of the pyramid, its section will be a triangle. First find the elevation of this triangle, making its altitude the given height stated ; then to show the thickness of the material cut through by the plane, find the elevation of the points 1, 2 in the plan on the IL, and through these points 1' 2', and parallel to the sides of the triangle, draw lines meeting in the axis in MECHANICAL AND ENGINEERING DRAWING 76 MECHANICAL AND ENGINEERING DRAWING the point a, cross-line the part cut by the section plane as shown, and the required sectional elevation is obtained. From the foregoing problems it will be seen that to obtain the elevation of an object from its plan alone, without other important data, would be impossible, as the heights and conformation of its different surfaces not seen in the plan must be known before its correct elevation can be attempted. It being necessary, at this stage of the student's progress in the study of our subject, that he should know something about the correct lining-in of his work in ink, we shall next explain the proper applica- tion of the different kinds of lines used in mechanical drawings, that he may be able to practise in spare moments on the sheets of drawings in pencil the results of his study, which it is assumed he has preserved. CHAPTER XI