Final answer:
In Engineering, a surface that must be machine finished for a better appearance and a closer fit refers to ensuring the component meets specified tolerances and limits, usually involving processes like grinding and honing for smoothness and accuracy.
Step-by-step explanation:
When a student asks about a surface that must be machine finished, requiring a better appearance and closer fit with all tolerances and limits observed, they are referring to a process known within the field of Engineering, especially precision engineering and manufacturing. This is relevant to machine parts that must interface precisely with other components, ensuring proper function and reliability. For a machine finish to be considered acceptable, it typically must be free from rough surface irregularities, holes and depressions, and maintain a uniform appearance.
Surfaces that require a higher-level finish are commonly subjected to machining processes such as grinding, lapping, or honing to achieve the desired level of smoothness and accuracy. In many cases, the specific requirements for the surface finish are indicated on the technical drawings or blueprints by symbols and notes, which dictate the degree of smoothness, manufacturing process, and exact tolerances that must be adhered to. For instance, a shiny, smooth surface is often required for parts that are visible or need a close fit for functional reasons, such as shafts and bearings.