Question

Which of the following gear is used for counting and timing purposes?

(a) High speed gears

(b) High power gears

(c) Low speed gears

(d) Precision gears

This question was posed to me in an international level competition.

This intriguing question originated from Sources of Errors in Manufacturing Gears topic in section Measurement and Testing of Gears of Engineering Metrology

Answer 1

Right answer is (d) Precision gears

The explanation is: Constant gearing ratio is the main requirement of the precision gears. Precision gears are generally used for indexing devices and measuring instruments, or in counting and timing purposes, and usually have small face width and small module.