Chapter 7

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