Threads, Fasteners & Springs — The form of a thread refers to the cross-sectional profile obtained by cutting the thread with a plane that contains the axis (e.g., V, square, trapezoidal forms).

Introduction / Context:
Thread form defines the profile shape (V, square, ACME) seen in an axial section. It determines flank angle, load-carrying characteristics, friction, and suitability for power transmission vs general fastening.

Given Data / Assumptions:

• Sectioning plane contains the screw axis.
• Profile edges define crest, root, and flanks.
• Function dictates the chosen form.

Concept / Approach:
Choosing form affects efficiency and strength. Square/ACME forms favor power transmission; V-threads favor self-locking and general-purpose fastening. The axial section captures the true defining geometry.

Step-by-Step Solution:
1) Section the threaded part in a plane through the axis.2) Observe the profile: angles, crest/root, flank widths.3) Classify the form (V, square, trapezoidal/ACME, buttress).4) Match form to functional requirements.

Verification / Alternative check:
Compare with standard templates/gauges; the axial cross-section determines compliance.

Why Other Options Are Wrong:
Color and torque are not geometric form; a perpendicular section (radial) does not define the standard form.

Common Pitfalls:
Misidentifying ACME vs square; ignoring flank angle implications on wear and efficiency.

Final Answer:
Correct