Mechanical Drawing Self-Taught Comprising instructions in the selection and preparation of drawing instruments, elementary instruction in practical mechanical drawing; together with examples in simple geometry and elementary mechanism, including screw threads, gear wheels, mechanical motions, engines and boilers

CHAPTER III.

Chapter 3221 wordsPublic domain

LINES AND CURVES.

Explanation of simple geometrical terms; radius; explanation of conventional dotted lines 48

A line at a right angle to another; a point; parallel lines 49

A line produced; a line bisected; a line bounding a circle; an arc of a circle; segments of a circle; the chord of an arc; a quadrant of a circle 50

A sector of a circle; a line tangent to a circle; a semicircle; centre of a circle; axis of a cylinder; to draw a circle that shall pass through three given points 51

To find the centre from which an arc of a circle has been struck; the degrees of a circle 52

The protractor 53

To find the angle of one line to another 54

To find the angles of three lines one to the other 55

Acute angles and obtuse angles 57

Triangles; right angle triangle; obtuse angle triangle; equilateral triangle; isosceles triangle 58

Scalene triangle; a quadrangle; quadrilateral or tetragon 59

Rhomboid; trapezoid; trapezium 60

The construction of polygons 61

The names of regular polygons 62

The angles of regular polygons; the ellipse 63

Form of a true ellipse 69

The use of a trammel for drawing an ellipse 72

To draw a parabola mechanically 73

To draw a parabola by lines 74

To draw a heart cam 75