Manufacturing notation on drawings Which drawing symbol is used to indicate that a surface is to be machined (that is, requires a specified finish or material removal)?

Introduction / Context:
Manufacturing drawings communicate not only size and location but also process intent. A common requirement is to show that certain faces must be machined to achieve a specified texture, flatness, or tolerance. This is done with standard surface finish symbols and notes.

Given Data / Assumptions:

• The question asks for the drafting symbol that flags machining on a surface.
• Industry uses standardized surface finish symbols and supplementary notes (for example, roughness values in microinches or micrometers).
• Terminology may vary, but the conventional phrase is the finish mark or surface finish symbol.

Concept / Approach:
The finish mark (also called the surface finish symbol) is the graphical indicator used in drawings to specify that material removal is required and, optionally, to state a quantitative roughness value. It may be a check-mark–like symbol with modifiers indicating lay, process, or value (for example, Ra 3.2 µm).

Step-by-Step Solution:

Verification / Alternative check:
Cross-check the parts list or process plan to confirm that the indicated surfaces indeed require machining operations such as milling, turning, or grinding. Drawings and travelers should be consistent.

Why Other Options Are Wrong:

• Machining mark: Not a standard term; it informally describes intent but is not the recognized symbol name.
• Roughness indicator: Describes the numeric requirement, but the question asks for the symbol indicating machining; the finish mark is the correct drafting term.
• Coordinate mark: Relates to datums or coordinate frames, not surface processing.

Common Pitfalls:
Forgetting to add the roughness value leads to ambiguity. Also, placing the symbol on dimension lines instead of on the surface leader can confuse manufacturing.

Final Answer:
Finish mark