Chapter 20, Problem 2P

Figure 20.A depicts the handles of two large wrenches, ratchet wrench and a pipe wrench. These components are traditionally forged from a ferrous alloy, or made from a cast steel or cast iron. For various reasons, alternative materials may be desired. The ratchet wrench is quite long, and reduced weight may be a reasonable desire. Both of these tools could be used in areas, such as a gas leak, where a non-sparking safety tool would be required. Current specifications for the ratchet handle call for a yield strength in excess of 50 ksi and a minimum of 2% elongation in all directions to ensure prevention of brittle fracture. The pipe wrench most likely has similar requirements.

FIGURE 20.A Handle segment of a large ratchet wrench and components of a pipe wrench.

1. Could a plastic or composite material be used to make a quality product with these additional properties? (NOTE: Metal jaw inserts can be used in the pipe wrench, enabling the other components to be considered as separate pieces.)
2. If so, how would you propose to manufacture the new handles?