$9.$ Tools of Unusual Geometry: $-$ Explain the applications and advantages of special$-$purpose cutting tools. $-$ How does the design of tools with unusual geometry address specific machining challenges? $-$ Discuss the limitations and potential innovations in tools of unusual geometry$\mathrm{.}10.$ Machining Economics: $-$ How do the characteristics of cutting tools impact overall machining costs? $-$ Discuss the economic implications of choosing long$-$lasting but expensive tool materials. $-$ Explain the concept of cost$-$effectiveness in the context of cutting tool selection$\mathrm{.}11.$ Tool Life and Wear: $-$ Define tool life and its significance in machining operations. $-$ How does tool wear affect the quality of machined surfaces? $-$ Discuss the factors influencing the wear resistance of cutting tools$\mathrm{.}12.$ Coolants and Lubricants: $-$ Explain the role of coolants and lubricants in cutting tool performance. $-$ How do cutting fluids contribute to heat dissipation during machining? $-$ Discuss the environmental considerations in selecting machining fluids.