To maximize tool life, you will use lower cutting speeds. Which statement best describes this relationship?

• A. Lower speeds maximize tool life
• B. Higher speeds maximize tool life
• C. Speeds have no effect on tool life
• D. Speeds only affect surface finish

Answer: (A)

Tool life is mainly governed by wear at the tool edge, which is driven by heat in the cutting zone. Cutting speed controls how much heat is generated during cutting: higher speeds raise the temperature more, accelerating wear mechanisms such as abrasion, diffusion of tool material, oxidation, and potential micro-cracking. By running at lower cutting speeds, the peak temperature stays lower, so the wear rate is reduced and the tool edge stays sharp longer, extending tool life. The trade-off is that slower speeds reduce material removal rate and productivity. The other statements don’t fit because higher speeds don’t maximize life, and speeds do influence tool life beyond just surface finish.