1. Engineering Measurement
Dr. Juma Y. Alaydi
Gauge Design

2. Gauge maker's Tolerance
Outline 1
Taylor’s Principle 2
Wear Allowance 3
Gauge maker's Tolerance 4
Example
April 18, 2019
Engineering Measurement

3. Taylor’s Principle Plug gauges Snap gauges April 18, 2019
Engineering Measurement

4. Gauge maker's Tolerance
April 18, 2019
Engineering Measurement

5. Second system (Revised Gauge Limits).
April 18, 2019
Engineering Measurement

6. Third system (Present British System).
April 18, 2019
Engineering Measurement

7. Example 50mm shaft and hole pair of H7d8 as per I.S. specification D =
Value of tolerance unit i= D
= microns = mm
Now hole is of type H and grade 7 = 16 i = 16* = 25 micron
For shaft d8
Tolerance IT8 = 25i =25× = mm.
Fundamental deviation for ‘d’ shaft
= - 16D 0.44 = - 16×
= - 16×5 = - 80 microns = mm.
April 18, 2019
Engineering Measurement

8. and Work tolerance = - 0.0391mm.
Upper deviation= mm.
and Work tolerance = mm.
Lower deviation = – = mm
(1)Plug gauges. According to new system, 'Go' gauges are given 1/10th of work
Tolerance in the tolerance zone and 'No Go' gauges, outside it.
Since work is less than 0.09mm.
So effect of wear in 'go' gauges is not considered
Work tolerance = 0.025mm
Limits for 'Go' gauges are mm. And mm.
for 'No Go' gauge, dimensions are = mm.
= mm
April 18, 2019
Engineering Measurement

9. Go’ Gauge No Go’ Gauge Go’ Gauge No Go’ Gauge
(2) Ring gauges
Dimensions for ‘Go’ gauge are =42.92mmAnd = mm
Dimensions for, ‘No go’, gauge are50-( ) = mm
And = mm
Answers: Plug gauge. Dimensions for
Go’ Gauge
No Go’ Gauge
50.000mm mm mm mm
Ring gauge: Dimensions for
Go’ Gauge
No Go’ Gauge mm mm mm mm
April 18, 2019
Engineering Measurement

10. Thank You !
Dr. Juma