Question

‘GO’ and ‘NO-GO’ snap gauges are to be designed for a hole \(36.000\begin{array}{*{20}{c}} { + 0.{\rm{\;}}070{\rm{\;}}}\\ { + 0.{\rm{\;}}010} \end{array}\) mm. Gauge tolerance can be taken as 5% of the hole tolerance. Following the ISO system of gauge design, the respective sizes of ‘GO’ and ‘NO GO’ gauges are
1. 36.013 mm and 36.067 mm
2. 36.015 mm and 36.065 mm
3. 36.018 mm and 36.062 mm
4. 36.020 mm and 36.060 mm

Answer 1

Correct Answer - Option 1 : 36.013 mm and 36.067 mm

Concept:

No-GO gauge is used to check the upper limit of a hole

∴ Size of No Go gauge = Upper limit of hole - Wear allowance - Gauge tolerance.

GO gauge is used to check the lower limit of hole

Now Size of Go gauge = Lower limit of hole + Wear allowance + Gauge tolerance.

Calculation:

Given:

Hole size = \(36.000\begin{array}{*{20}{c}} { + 0.{\rm{\;}}070{\rm{\;}}}\\ { + 0.{\rm{\;}}010} \end{array}\), Gauge tolerance = 5% of the hole tolerance.

The upper limit of the shaft = 36.070 mm.

The lower limit of the shaft = 36.010 mm.

Tolerance = Upper limit - Lower limit

Tolerance = 36.070 - 36.010 = 0.060 mm.

Gauge tolerance = 0.05 × 0.060 mm = 0.003 mm

As wear allowance is not mentioned we can ignore this.

Size of Go gauge = Lower limit of hole + Gauge tolerance.

= 36.010 + 0.003 = 36.013 mm

Size of NO-GO gauge = Upper limit of hole - Gauge tolerance

= 36.070 - 0.003 = 36.067 mm.