What does **surface finish** refer to in manufacturing?
C
Texture and quality of the surface after machining
Analysis & Theory
Surface finish refers to the texture, smoothness, and irregularities on the surface of a part after processing.
Which unit is used to measure **surface roughness**?
Analysis & Theory
Surface roughness is commonly measured in micrometers (µm).
What is the symbol used to represent **surface finish** in engineering drawings?
C
A check-like symbol without a horizontal line
Analysis & Theory
Surface finish is indicated by a symbol that looks like a check mark (⏤╱), with or without a horizontal bar.
What does it mean when the **surface finish symbol has a horizontal bar**?
A
No machining is allowed
B
Only grinding is allowed
Analysis & Theory
A surface finish symbol with a horizontal bar (⏤╱) indicates that material removal by machining is required.
What does a **circle** on the surface finish symbol indicate?
B
No material removal allowed
Analysis & Theory
A circle on the surface finish symbol (⌀╱) means that no material removal is allowed — the surface must be left as cast or forged.
Which of the following indicates the **smoothest surface finish**?
Analysis & Theory
Lower Ra values mean smoother surfaces. Ra 0.4 µm is smoother than the others.
Which process usually gives the **smoothest surface finish**?
Analysis & Theory
Grinding provides a very smooth surface finish, often less than 1 µm Ra.
What does **Ra** stand for in surface finish?
Analysis & Theory
Ra is the average of absolute values of surface deviations — called Roughness Average.
Why is surface finish important in mechanical parts?
C
For better mating, wear resistance, and fatigue strength
Analysis & Theory
Surface finish affects function, wear resistance, and performance in mating parts.
Which symbol indicates **basic surface finish without any machining**?
D
⏤╱ with roughness value
Analysis & Theory
A check mark (╱) alone indicates surface finish without specifying machining or values.