Question

Which of the following is not true for hole and shaft basis systems?

(a) Hole basis system is generally preferred over shaft basis system

(b) Shaft basis system can be used when products are made from bright drawn bars

(c) Choice of the system depends upon nature of the product

(d) In hole basis system, allowances are applied to the hole

This question was posed to me during an interview for a job.

This intriguing question comes from Guide for Selection of Fits topic in section Limits, Fits and Gauges of Engineering Metrology

Answer 1

Right answer is (d) In hole basis system, allowances are applied to the hole

The best explanation: Hole basis system is preferred because it is easy to produce a shaft with specified tolerances than hole. In hole basis system, all tolerances are applied to shaft and hole size is taken as basic size.