upon a perpendicular to the edge b'-d drawn from //. Draw a parallel to b'-d through this point and the true width of B will be obtained. Next we locate upon it points c ami /, by projecting perpendiculars from points a and c. Join these points to b! and d respectively, and the true size and shape of the angle piece is obtained with the bevels as shown.

To obtain the Cuts for Purlins against Hips-—Pigs. 13 and 14 are the plan and elevation of the angle of a hipped roof showing the ends of the purlins fitting against the hip rafter. These are the usual projections given, from which we obtain the bevels by developing the inclined surfaces of the purlin into a horizontal plane.

With point c in Fig. 14 (the top edge of the purlin) as centre, and the widths of the edge and side as radii, describe arcs cutting the horizontal line in points a' and b'. Drop projectors from these points into the plan and intersect them by perpendiculars from the edges of the purlin, where they come in contact with the hip, thus obtaining points «*■ //; join these to point c' and the bevels are disclosed.

Oblique Cuts in Angle Braces —Figs. 1 and 2, page 146, are the plan and elevation respectively of a post or standard resting upon a sole piece and counter braced. To utilise the space iullv, different arrangements of the braces are shown on either side, but in practice they would be alike on each side. The brace on the left side, as will be seen by its plan, lies parallel to the plane it is drawn upon, therefore all its edges are shown in actual length and position and the bevels are obtainable directly from the drawing.

Upon the right-hand side the brace is shown with one of its diagonals vertical, or, stated otherwise, it lies with its arris edges in a vertical plane ; this can be better seen in the side elevation, Fig. 3. A bevel set to the projection would give the correct shape for the housing into the post, but not the bevel to apply to the sloping sides of the. brace for marking the shoulder cuts. These must be obtained by developing the sloping surfaces or turmng them into the vertical plane. Perhaps it would be clearer to say that the two edges must k

Obtaining Bevels upon Oblique Planes

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Freehand Sketching An Introduction

Freehand Sketching An Introduction

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