Page 16 - CITS - ED - Mechanical

ENGINEERING DRAWING - CITS

Circles, arcs and ellipse

Follow the procedures and construct the following.

Procedure

Exercise 1.1
Draw a tangent to a given circle of φ 70 mm at any point `P' on it. (Fig 1)
• Draw a circle of φ 50 with `O' as centre.
• Mark the given point `P' on the circumference of the circle.
• Join OP.
• Draw a line RS perpendicular to PO through `P'.
• RS is the tangent at `P'.

Fig 1

Exercise 1.2
Draw an arc of given radius (R 20 mm) to touch to two straight lines (50 mm each) at right angles. (Fig 2)
• Draw the lines AB and AC (50 mm each) at right angles.
• With `A' as centre and given radius (R 20 mm) draw an arc to cut lines AB and AC at E and F.
• With E and F as centres and the radius given (R 20 mm), draw arcs to intersect each other at `O'.
• Use `O' as centre and with same radius (R 20) draw a curve (arc) which will just touch the given lines AB and
AC.

Fig 2

Exercise 1.3
Draw an arc of given radius (R 20 mm) to touch the given lines which make an acute angle between them (assume
60°). (Fig 3)
• Draw an acute angle BAC (60°).

• Draw a horizontal parallel line EF at a distance equal to the given radius (20 mm).

3
CITS :Engineering Drawing (Mechanical) - Exercise 1