Limit gauges are inspection gauges used to check if a component's dimensions fall within specified upper and lower tolerance limits. They include NO-GO and GO gauges. Common types are plug, ring, snap, taper, thread, and form gauges. Plug gauges come in double-ended or progressive styles. Ring gauges check shaft diameters. Snap gauges check external dimensions and come in double-ended, progressive, or adjustable styles. Taper gauges check tapers in plain or tanged styles. Thread gauges check pitch diameters. Form gauges check profile contours. Limit gauges help speed up inspection processes and ensure component quality.

1. Limit Gauges
Dr.S.BENJAMIN FRANKLIN
Associate Professor Gr1
Department of Mechanical Engineering
Sri Ramakrishna Institute of Technology

2. Limit Gauges
• Limit gauge is not a measuring gauge
• They are used as inspection gauges
• These are also called NO and NOGO gauges.
• They are used to the limit size of the work to
be measured.
Purposes of using limit gauges
Components are manufactured as per the
specified tolerance limits such as upper limit
and lower limit.

3. Limit Gauges
• The dimensions of each component should be
within the upper and lower limits
• If the dimensions are outside these limits, the
components will be rejected
• If any measuring instruments are used to
check these dimensions, the process
consumes more time.

4. Classifications of slip gauges
1.Based on the consistency in manufacturing and
inspection
• Working gauge – Gauges are used on the bench
or machine
• Inspection gauge – Gauges are used by the
inspection personnel to inspect the
manufactured parts
• Reference or Master gauge – Gauges are used
only for checking the size or condition of other
gauges

5. Classifications of slip gauges
2.Depending on the elements to be checked
Hole gauge – It is used to check the dimensions of
the hole present in the element
Shaft gauge-It is used to check the dimensions of
the shaft
Taper gauge – It is used to check the dimensions of
the tapers
Thread gauge-It is used to check the dimensions of
the threading element
Form gauge-It is used to check the forms of the

6. Classifications of slip gauges
3.According to shape or purpose for which each is
used
 Plug gauge
 Ring gauge
 Snap gauge
 Taper gauge
 Thread gauge
 Form gauge
 Thickness gauge or Peeler gauge
 Indicating gauge
 Air-operated gauge

7. Plug gauge
-Double ended plug gauge
-Progressive type

8. Double ended plug gauge

9. Ring Gauge
Ring gauges are
checking
external
dimensions of
the shaft

10. Taper plug gauge
Taper plug
gauge-plain type
Taper plug
gauge-tanged type
Taper ring gauge-
plain type
Taper ring gauge-
tanged type

11. Taper plug gauge-tanged type
Taper ring gauge –plain type

12. Taper Ring Gauge –Tanged type

13. SNAP GAUGE
Snap gauges are used for
checking the external
dimensions.Shafts are
mainly checked by snap
gauges
1.Double ended snap
gauge – two ends in the
form of anvils
2.Progressive snap gauge
3.Adjustable snap gauge
4.Plate type double ended
snap gauge

14. Progressive type snap
gauge-caliper gauge
Checking large
dimensions upto 100 mm
Adjustable snap- checking
large size shafts shafed frame
I section.

15. Plate type double ended snap
gauge-Thin plate has two
ends.This type is used for sizes
from 2mm to 100 mm.
Plate type single ended
progressive snap gauge-thin
plate and only one end with
GO and NOGO size limits

16. Combined limit
gauge
A spherical projections S is
provided with NO and
NOGO dimensions marked
in a single gauge.
While using GO gauge ,the
handle is parallel to the
axes of the hole normal to
axes for NOGO gauge

17. Thread Gauge
Plug thread gauge

18. Ring thread gauge –used to check the pitch
dia of thread

19. F0rm Gauges
Form gauges
may be used to
check the
contour of a
profile of a work
piece for to a
conformance to
a certain shape
or form
specifications

20. Screw pitch gauge
Radius and fillet gauges

21. Feeler gauge Plate gauge

22. Wire gauge