Chapter VII: Examples in Bolts, Nuts and Polygons

To represent the thread of a small screw 112

A bolt with a hexagon head 113

United States standard sizes for forged or unfinished bolts and nuts 116

The basis of the Franklin Institute or United States standard for bolts
and nuts; hexagonal or hexagon heads of bolts 118

Comparison of hexagon and square heads of bolts; chamfers 120

Without chamfer; best plan for view of both square and hexagon heads 123

Drawing different views of hexagon heads 125

To draw a square-headed bolt; to draw the end view of a hexagon head 125

Use of the triangle to divide circles 129

Scales giving the length of the sides of polygons 135

To find what a square body which measures one inch on each side measures
across the corners; to find what diameter a cylindrical piece of
wood must be turned to which is to be squared, and each side of which
square must measure an inch 136

To find a radius across corners of a hexagon or a six sided figure, the
length of a side being an inch 138

To draw a stud 142

To pencil in a cap nut; pencilling for a link having the hubs on one side
only 145

Link with hubs on both sides; pencil lines for a double eye or a knuckle
joint 146

Double eye or knuckle joint with an offset; a connecting rod end 147

A rod end with a round stem 148

A bolt with a square under the head 149

Example in which the corner where the round stem meets the square
under the head is sharp; a centre punch giving an example in
which the flat sides gradually run out upon a circle, the edges
forming curves 150

CHAPTER VIII.

SCREW THREADS AND SPIRALS.

Screw threads for small bolts with the angles of the thread drawn in, and
the method of doing this 152

A double thread; a round top and bottom thread such as the Whitworth
thread; a left hand thread; to draw screw threads of a large
diameter 156

Drawing the curves for screw threads 157

To draw the United States standard thread 160

To draw a square thread 162

Form of template for drawing the curves of threads 165

To show the thread depth in a top or end view of a nut; to draw a spiral
spring 166

To obtain an accurate division of the lines that divide the pitch 167

CHAPTER IX.

EXAMPLES FOR PRACTICE.

A locomotive spring; a stuffing box and gland; working drawings of a
coupling rod; dimensions and directions marked; a connecting rod
drawn and put together as it would be for the lathe, vise, or erecting
shop 169

Drawings for the blacksmith 172

A locomotive frame 174

Reducing scales 175

Making a drawing to scale 177

CHAPTER X.

PROJECTIONS.

A spiral wound around a cylinder whose end is cut off at an angle 178

A cylindrical body joining another at a right-angle; a Tee for
example 180

Other examples of Tees 181

Example of a cylinder intersecting a cone 186

A cylindrical body whose top face if viewed from one point would appear as
a straight line, or from another a circle 188