How to

Learn to how draw.

Drawing Gear Wheels

The names given to the various lines of a tooth on a gear-wheel are as follows: In Figure 233, A is the face and B the flank of a tooth, while C is the point, and D the root of the tooth; E is the height or depth, and F the breadth. P P is

Screw Threads And Spirals

Fig. 202. Fig. 203. The screw thread for small bolts is represented by thick a