Threads, Fasteners & Springs — Multiple-start threads have two or more ridges; their lead equals pitch multiplied by the number of starts. Saying “one ridge and lead = pitch” is incorrect.

Introduction / Context:In multi-start threads, two or more identical helices are interleaved. This design increases the lead for quicker axial travel per revolution, commonly used in quick-open caps or motion mechanisms.

Given Data / Assumptions:

• Number of starts >= 2 for multiple threads.
• Pitch is measured between adjacent threads on the same start.
• Lead = pitch * number_of_starts.

Concept / Approach:Because multiple ridges exist, the axial advance after one full turn spans across multiple thread spaces of the same start count, hence lead grows proportionally to starts.

Step-by-Step Solution:1) Determine starts by tracing one ridge around the cylinder.2) Measure pitch along that same start.3) Compute lead = pitch * starts.4) Conclude the statement is incorrect since it claims one ridge and lead = pitch.

Verification / Alternative check:For a double-start with pitch 2 mm, lead = 4 mm; observation after one turn confirms 4 mm axial movement.

Why Other Options Are Wrong:Suggesting one ridge or lead = pitch for all types ignores definitions; dividing pitch by starts reverses the correct relation.

Common Pitfalls:Counting pitch across different starts; mistaking lead for thread height.

Final Answer:Incorrect