will be used for metrology and measurements

1. GAUGES By
KANAKA RaZ

3. GAUGES
• Gauges perform an essential services in any
scheme of quantity production on an
interchangeable basis
• A gauge (or Limit Gauge) is a tool or instrument
to measure or compare a component.
• It is employed in the sense of an instrument
which having fixed dimension, is used to
determine whether the size of some
component exceeds or is less than the size of
the gauge itself

4.  Gauges are used for dimensional control of
the component parts , their function being to
establish whether or not surface levels lie
within the zone specified by the designer.
 Gauges must be manufactured & checked
with reference to standard of length, which in
turn is related to a fundamental length
standard. The standard of length is then
transferred through the gauge to the
component

5.  The true value of a gauge is measured by its
accuracy & service life which, in turn,
depends on the workmanship & materials
used in its manufacture. Since all gauges are
continually subject to abrasive wear while in
use, the selection of the proper material is of
great importance
 High carbon steel & alloy tool steels have
been the principal materials for manufacture
of such gauges

10. Classification
• According to design
– single limit and double limit gauges
– single ended and double ended gauges
– fixed and adjustable gauges

12. Standard gauge
• If a gauge is made as an exact copy of the
mating part of the component to be checked
ex: bush for shaft

13. Limit gauge
• Used widely in industries
• For two permissible limits of the dimension of
a part
• Two gauges are required for two limits
• These are GO and NO GO gauges
• GO gauge foe MML
• NO GO for LML

14. Limit Gauge
• Limit gauges are made to the limits of the dimensions of
the part to be tested. There are two limit of dimensions,
so we need two limit gauge.
• ‘Go gauge’ should pass through or over a part while ‘Not
Go gauge 'should not pass through or over the part.

15. Limit gauges

16. Limit gauges

18. Types of limit plug gauges
1. Solid type
2. Renewable type – taper inserted type
3. Fastened type – single, double ended
4. Flat type
5. Progressive type
6. Pilot plug gauge
7. Combined dual purpose type

19. Solid type

20. Renewable type

21. Renewable type

22. Fastened type limit plug gauge

23. Fastened type limit plug gauge

24. Fastened type limit plug gauge

25. Progressive type

26. Flat type

27. Pilot type plug gauge

28. Combined dual purpose limit gauge

29. Shell form plug gauge

34. Snap gauge – Double ended

35. Snap gauge
Adjustable

38. Ring Gauge- plain
From 3-70 mm From 70-250mm

39. Ring Gauge-

40. Ring gauge

41. TAPER GAUGE
• The most satisfactory method of testing a
taper is to use taper gauges.
• They are also used to gauge the diameter of
the taper at some point.
• Taper gauges are made in both the plug and
ring styles and, in general, follow the same
standard construction as plug and ring gauges.

42. Taper plug gauge

43. TAPER GAUGE

44. Plug gauge

45. THREAD GAUGE
• Thread gauges are used to check the pitch
diameter of the thread.
• For checking internal threads (nut, bushes, etc.),
plug thread gauges are used, while for checking
external threads (screws, bolts, etc.), ring thread
gauges are used.
• Single-piece thread gauges serve for measuring
small diameters.
• For large diameters the gauges are made with
removable plugs machined with a tang.

46. Threaded
Spline

47. THREAD GAUGE

48. FORM GAUGE
• Form gauges may be used to check the
contour of a profile of work piece for
conformance to certain shape or form
specifications.
Template Gauge
• It is made from sheet steel. It is also called
profile gauge. A profile gauge may contain two
outlines that represent the limits within which
a profile must lie

50. SCREW PITCH GAUGE
• Screw pitch gauges are used in picking out a
required screw and for checking the pitch of the
screw threads.
• They consist of a number of flat blades which are
cut out to a given pitch and pivoted in a holder.
• Each blade is stamped with the pitch or number
of thread per inch and the holder bears an
identifying number designing the thread it is
intended for.

52. RADIUS AND FILLET GAUGE
• The function of these gauges is to check the
radius of curvature of convex and concave
surfaces over a range from 1 to 25 mm.
• The gauges are made in sets of thin plates
curved to different radius at the ends.
• Each set consists of 16 convex and 16 concave
blades.

53. Radius

54. FEELER GAUGE
• Feeler gauges are used for checking clearances
between mating surfaces.
• They are made in form of a set of steel, precision
machined blade 0.03 to 1.0 mm thick and 100
mm long.
• Each blade has an indication of its thickness.
• To find the size of the clearance, one or two
blades are inserted and tried for a fit between the
contacting surfaces until blades of suitable
thickness are found.

55. Feeler

56. INDICATING GAUGES
• Indicating gauges employ a means to magnify
how much a dimension deviates, plus or minus,
from a given standard to which the gauge has
been set.
• They are intended for measuring errors in
geometrical form and size, and for testing
surfaces for their true position with respect to
one another.
• Indicating gauges can be of a dial or lever type.

57. Materials which are used for making gauges are high carbon and
alloy steels, cemented carbides, etc.

59. 59
Taylor’s Principle
• Go Gauge should always be so designed that
it will cover the Maximum Metal
Condition(MMC) of as many dimensions as
possible in the same limit gauge,
whereas Not Go gauge to cover the minimum
metal condition of one dimension only.

62. 62
Design of Limit Gauge
• Allocation of Tolerance
– Manufacturing Tolerance
– Wear Allowance
• Taylor’s Principle of gauge Design
• Fixing of Gauge elements with handles
– Taper lock design
– Trilock Design
• Provision of Guards
• Provision of Pilot Correct Centering
• Materials
• Hardness and Surface finish
• Rigidity
• Alignment of Gauge faces

63. 63
Allocation of Tolerance
Manufacturing Tolerance
• It is economically impractical to attempt to make “Go” and “Not Go”
gauges exactly to the two limits of work tolerance.
• Limit gauges are made 10 times more accurate than the tolerances
they are going to control.

64. 64
Allocation of Mfg Tolerance

65. 65
Allocation of Tolerance
Wear Allowance
• The surface of “Go” gauge is constantly rub
against the surface of the part in inspection and loose
their initial size.
• The size of plug gauge is reduced but size of snap
gauge is increased.
• 10% wear allowance is provided only for the “GO”
gauge if working tolerance is greater than 0.09 mm.

66. 66
Allocation of Wear Allowance

67. 67
KEY WORDS
Standard Gauges : These are made to the nominal size of the parts to
be tested.
Limit Gauges : These are „go‟ and „no go‟ gauges.
Plug Gauges : These are used for checking holes of many different
shapes and sizes.
Ring Gauges : External diameter measuring gauges.
Taper Gauges : Taper testing gauges.
Snap Gauges : These are used for checking shafts.
Thread Gauges : These are used for pitch diameter of the thread.
Form Gauges : These are used to check the contour of a profile.
Feller Gauges : For checking the clearance between the mating
surfaces.
Indicating Gauges : To measure the position of the surfaces.