Question

assignment 2: line problems

1. draw accurately two line problems using appropriate type and thickness of lines. scale 2:1 construction.

engineering drawing tie 1101 assignment 2
assignment 2
answer any two questions.
use scale 2:1
(diagram labels: r13, r18, r8, 40, φ60, 135°, 45°)

Explanation:

Step1: Analyze the First Diagram (Left)

The left diagram has circular arcs (R8, R13, R18) and a rectangular - like shape with rounded ends. First, we need to consider the scale 2:1. The horizontal dimension given is 40, so in the scaled drawing (2:1), the length will be \(40\times2 = 80\). For the circular arcs, the radii in the scaled drawing will be \(R8\times2=R16\), \(R13\times2 = R26\), \(R18\times2=R36\). We start by drawing the center lines (horizontal and vertical) to establish the symmetry. Then, we draw the rectangular part (with length 80 and the appropriate width, considering the radii of the rounded ends) and the circular arcs on the top, bottom, left, and right as per the radii.

Step2: Analyze the Second Diagram (Right)

The right diagram has a circle with diameter \(\phi60\), so the radius in the scaled drawing (2:1) is \(\frac{60}{2}\times2 = 60\) (or diameter \(60\times2 = 120\)). There are angles of \(135^{\circ}\) and \(45^{\circ}\) and a polygonal shape inside the circle. First, draw the circle with the scaled diameter. Then, draw the center lines (horizontal and vertical). Using a protractor (or geometric construction for angles), mark the angles \(135^{\circ}\) and \(45^{\circ}\) to draw the lines of the polygon inside the circle, ensuring symmetry.

Step3: Line Types and Thickness

For engineering drawing, we use different line types: center lines (thin, long - dashed - dotted), visible lines (thick), and maybe hidden lines (if any, but in these diagrams, there are no hidden features shown). So, we draw center lines first (thin) to establish the symmetry axes. Then, draw the visible lines (thick) for the outlines of the shapes (arcs, rectangles, circle, polygon).

Answer:

To solve this engineering drawing problem (scale 2:1):

For the Left Diagram:

1. Scale the Dimensions: Multiply all given dimensions by 2. The horizontal length becomes \(40\times2 = 80\), radii: \(R8

ightarrow R16\), \(R13
ightarrow R26\), \(R18
ightarrow R36\).

1. Draw Center Lines: Draw horizontal and vertical center lines to show symmetry.
2. Draw Shapes:

• Draw the rectangular part (length = 80, width determined by the distance between the arcs) with rounded ends (using the scaled radii \(R16\), \(R26\), \(R36\) for the arcs on the top, bottom, left, and right).
• Draw the concentric arcs (top and bottom) with radii \(R16\), \(R26\), \(R36\) centered on the vertical center line.

For the Right Diagram:

1. Scale the Circle: The diameter \(\phi60\) scales to \(\phi120\) (radius \(r = 60\)). Draw the circle with this diameter.
2. Draw Center Lines: Draw horizontal and vertical center lines.
3. Draw Angles and Polygon:

• Using a protractor, mark \(135^{\circ}\) and \(45^{\circ}\) angles from the horizontal center line.
• Draw the polygonal lines inside the circle, ensuring they are symmetric and connect appropriately to form the shape.

Line Types:

• Center Lines: Thin, long - dashed - dotted lines for symmetry axes.
• Visible Lines: Thick lines for the outlines of all shapes (arcs, rectangles, circle, polygon).

(Note: This is a drawing - based solution, and the actual drawing should be done on drawing paper or using CAD software with the above - mentioned steps for scaling, line types, and geometric construction.)