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

CHAPTER XI.

DRAWING GEAR WHEELS.

Names of the curves and lines of gear teeth 193

How to draw spur wheel teeth 194

Professor Willis' scale of tooth proportions 195

The application of the scale 197

How to find the curve for the tooth face 198

To trace hypocycloides for the flanks of teeth 200

Sectional view of a section of a wheel for showing the dimensions through
the arms and hub 202

To draw an edge view of a wheel; rules for drawing the teeth of wheels;
bevel gear wheels 203

The construction to find the curves 204

To draw the arcs for the teeth 205

To draw the pitch circle of the inner and small end of the pinion
teeth 206

One-half of a bevel gear and an edge view projected from the same 207

A pair of bevel wheels shown in section; drawing of a part of an Ames
lathe feed motion; small bevel gears 208

Example in which part of the gear is shown with teeth in, and the
remainder illustrated by circles; drawings of part of the feed
motion of a Niles horizontal tool work boring mill 209

Three bevel gears, one of which is line-shaded; the construction of oval
gearing; Professor Rankine's process for rectifying and subdividing
circular arcs 210

Various examples of laying out gear wheels 214

CHAPTER XII.

PLOTTING MECHANICAL MOTIONS.

To find how much motion an eccentric will give to its rod 223

To find how