Tooth layout: For spur and bevel gears, tooth spacing around the pitch circle/cone is achieved by dividing the circle into equal angular increments (equal tooth angles). Decide whether this statement is correct.

Introduction / Context: Tooth count Z determines circular pitch and angular pitch. Accurate, uniform spacing ensures smooth meshing and constant velocity ratio. This item checks whether equal-angle division is the correct basis for tooth layout.

Given Data / Assumptions:

• Z teeth around a pitch circle (spur) or pitch cone (bevel).
• Angular pitch tau = 360/Z degrees.
• Manufacturing uses indexing or CNC interpolation to achieve uniform spacing.

Concept / Approach: Equal angular spacing ensures each tooth engages uniformly with a mating gear. Chordal and arc measurements relate to the same angular division; modern processes use rotary indexing or electronic gearing to guarantee tau for each tooth space.

Step-by-Step Solution:1) Compute angular pitch tau = 360/Z.2) Index the blank successively by tau for each cut.3) Verify cumulative error does not exceed tolerance.4) Inspect with span measurement or composite testing.

Verification / Alternative check: Gear standards define pitch errors relative to ideal equal-angle spacing; inspection charts track deviations tooth-to-tooth.

Why Other Options Are Wrong:Chord equality is a consequence of equal angles on a given radius; it is not an alternative principle.Random placement would destroy conjugacy, causing noise and wear.

Common Pitfalls: Cumulative indexing error; thermal drift in CNC; miscalibrated rotary tables.

Final Answer: Correct