Types of Gauges in Metrology [Notes with PDF]

Metrology is a significant department of Mechanical engineering that deals with the measurement of a workpiece. Metrology is oftentimes called the science of measurement that depends upon two significant factors.

The factors are time and quantity, which has to be measured by an engineer in order to ensure the precision of a workpiece.

Every material has some degree of error in it that can impact negatively on the mechanical efficiency of a machine component. Therefore, for removing those errors from a workpiece some measurement tools are devised by engineers such as surface texture measurement device, tolerance measurement device, screws threads measurement device and so on.

Gauge is the tool used by engineers to rectify errors in terms of linear measurement. Linear measurement deals with measuring lengths, heights, diameters, etc.

It is also used by engineers to secure variance in a workpiece.

In this assessment, Gauge and its types are critically analyzed briefly in all the possible ways. Everyone is seeking for an appropriate knowledge about Gauges due to the conciseness of the description.

Definition of Gauge:

A gauge is an inspection tool that is used by engineers to measure the tolerance limit of a component. Gauges are mainly utilized by engineers in order to segregate the appropriate dimension of a workpiece.

Some fundamental limitations are present within which a Gauge should be made by manufacturers.

Therefore, if the Gauge seemed accurate in relation to ideal Gauge then the workpiece should be measured with that Gauge.

The operator can use Gauge without having vast knowledge in operating those mechanical components. Also, Gauges consume less time as compared to other measuring devices.

Types of Gauges in Metrology:

Plain Gauge is defined as the dimension measuring or inspective tools, without a scale to measure any manufacturing part of tools.

In order to check shafts and the holes, Plain Gauge is used.

Plain Gauge is classified into four different types. Those types are in follows:

  • Depending on the manufacturing principle and type
    • Standard Gauge
    • Limit Gauge
    • Indicating Gauge
    • Combination Gauge
  • Depending on the purpose
    • Workshop Gauge
    • Inspection Gauge
    • Master Gauge (Reference Gauge)
  • Depending on the function
    • Dimension Measuring Gauge
      • Inside Dimension Measuring Gauge
        • Plug Gauge
        • Pin Gauge
      • Outside Dimension Measuring Gauge
        • Snap Gauge
        • Ring Gauge
      • Both sides Dimension Measuring Gauge
        • Calliper Gauge
        • Geometric Measuring Gauge
        • Gauges for concentricity
        • Gauge of Taper
        • Gauge of Profile
  • Depending on the Design
    • Single limit and Double limit
    • Single-ended and Double-ended
    • Fixed and Fastened
    • Geometry Measuring Gauge

#1 Depending on the Manufacturing Principle and Type:

Standard Gauge: 

Standard Gauge can be defined as the measuring tool that checks the copy of the mating part of the material. This gauge cannot be used by an engineer due to the existence of tolerance in a workpiece.

standard gauge

Limit Gauge: 

Limit Gauge is defined as the gauge that is used to measure a component by two limits, one is High and another is Low. So, there are two gauges to measure the dimension of the material. Two gauges are the Go-Gauge and the Not-Go-Gauge.

The part of the component has to pass through the Go-Gauge and for the Not-Go-Gauge, it has not to pass. This gauge is widely used in industries.

Limit gauge
limit gauges

Indicating Gauge: 

Indicating Gauge is defined as the gauge which is used to measure a part of a material and shows the measurement on a display. This gauge displays the measurement on the indicator or display, so it is termed as the Indicating Gauge.

This gauge is complex than other gauges. The best example of the Indicating Gauge is Dial Gauge. Nowadays such indicating gauge has a system of the visual display.

Dial Indicator

Combination Gauge: 

Combination Gauge is defined as the gauge which can take more than one dimension of the parts of the material consecutively. It is very useful as at a time more than one measurement of the parts can be taken. It consumes less time and produces more efficient results.

#2 Depending on the Purpose:

Workshop Gauge: 

Workshop Gauge is defined as the gauge which is used to measure the parts of the material at the time of production. This gauge is used in the production time at the workshop so that this gauge is named as the Workshop Gauge.

The Workshop gauge is designed like that, where the tolerance is in the center-line. So that Workshop Gauge is very useful in the plants or workshops rather than the others.

Inspection Gauge: 

Inspection Gauge is defined as the gauge which is used by the inspectors in the plants after finishing the manufacturing of the products to accept it. As the acceptance or the rejection is depending on the gauge measurement so that tolerance of this Inspection Gauge is slightly more than the Workshop Gauge.

If the tolerance of the material part is high then it is accepted otherwise the material should be rejected. 

Master Gauge (Reference Gauge): 

Master Gauge is defined as the gauge to check the other gauges. As the expenditure is involved, the measuring instruments, optimizers, comparators, slip gauges, etc. are checked by the master gauge or reference gauge.

slip gauge

All the other gauges are checked by this gauge so that this gauge is called the Master Gauge. It is very useful because the efficiency of the other gauges depends on the master gauge.

If the master gauge cannot check the other gauges or instruments properly then those gauges and instruments cannot give accurate results.

#3 Depending on the function

Dimension Measuring Gauge: 

Dimension Measuring Gauge is defined as the gauge which measures very small parameters of the parts of the material with very high accuracy. These dimensions are depth, height, diameter, etc. and are measured by the Dimension Measuring Gauge.

This Gauge is used to get very specific and accurate dimensions. This Dimension Measuring Gauge is classified in the other three types. Those are as follows:

Inside Dimension Measuring Gauge: 

Inside Dimension Measuring Gauge is used to measure the inner or inside diameter, width, height, etc. In an example, the inner diameter of a bolt can be measured by Plug Gauge.

Inside Dimension Measuring Gauge is classified in different types. Those are as follows:

  1. Plug Gauge
  2. Pin Gauge

Plug Gauge: 

Plug Gauge
Plug Gauge

Plug Gauge is a cylindrical shaped Go and Not-Go type Gauge. It is used to measure the diameter of a hole like things with accuracy. In order to measure the parts, it has to pass a Measurement and another one has not to pass the Measurement. That is called Go and Not-Go measurement.

Pin Gauge: 

set of pin gauge

Pin Gauge generally works on the same working principle as the Plug Gauge, which is used to measure the diameter which is more than 75mm. Measurement of the width of the slots or grooves is done by Pin Gauge. It is measured across cylinder bore and the gauge placed as lengthwise.


Outside Dimension Measuring Gauge:

Dimension Measuring Gauge is used to measure the outer or outside diameter, width, height, etc. As an example, the outer diameter of a bolt can be measured by Snap Gauge.

Dimension Measuring Gauge is classified in different types. Those are as follows:

  • Snap Gauge
  • Ring Gauge

Snap Gauge: 

snap gauges

The Snap Gauge is the gauge which is U-shaped Go and Not-Go type gauge. It has jaws by which it checks the accuracy and tolerance. In order to measure the parts, it has to pass a Measurement and another one has not to pass the Measurement. That is called Go and Not-Go measurement. Here Go is a high or maximum limit and the Not-Go is the low or minimum limit.

types of snap gauges
ring gauge

Ring Gauge: 

The Ring Gauge is the same as the snap gauge but it is separated the Go and Not-Go pass or in a single ring.

ring gauge diagram

Both Sides Dimension Measuring Gauge:

Both Sides Dimension Measuring Gauge is used to measure the outer or outside and inner or the inside, both diameters, width, height, etc. In an example, the outer and inner both the diameters of a bolt can be measured by Calipers.

Outside Dimension Measuring Gauge is classified in different types. And those are

  1. Caliper Gauge
  2. Geometric Measuring Gauge
  3. Gauges for concentricity
  4. Gauge of Taper
  5. Gauge of Profile

Caliper Gauge: 

The Caliper Gauge is the gauge that is used to measure the distance of an object, between the two different sides. It is very useful as it can give more accurate results and very easy to use. Such examples are Vernier caliper, Dial caliper, Digital Caliper, Micrometre caliper, etc.

vernier caliper gauge

Geometric Measuring Gauge:

Geometric measuring gauges are defined as a measuring device that can measure its concentricity, taper, and profile. Mainly the geometric measuring gauge is used to measure the roughness or unevenness of the surface. There are several types of measuring and calculating procedures for roughness characterization through its concentricity, profile and so on.

Gauges for Concentricity:

The concentricity gauge is used to measure runout by revolving the cylinder or the loaded round on two pairs of bearings that are captured in anodized aluminum blocks. This gauge mainly measures the circle of the plane.

Gauges for taper:

The taper gauge is basically used to measure the internal tapers. This gauge looks like an internal gauge in the shape of a frustum of a cone.

Gauges for Profile:

The profile gauge or contour gauge is a tool that is used to draw the profile or copy it on to another surface.

Depending on the Design

Single limit and Double limit:

The single limit gauge has a jaw that is fixed that makes the gauge limited, But in the case of the double limit gauge, it has a movable jaw that can be doubled with the help of the adjustable jaws.

Single-ended and Double-ended:

The single-end gauge has a single end that could be either ‘Go end’ or ‘No-go end’. But in Double-end gauge has both ends, it’s one end is ‘Go end’ another one is ‘No-go end’.

Fixed and Fastened Gauges:

In fixed end gauge both jaws are fixed at the same time, but in Fastened end gauge only one jaw can move or adjustable. These types are mainly a type of snap gauges.

Ending Thoughts of Gauges:

Concerning the above description of Gauges and its types, it can be asserted that the field of metrology is incomplete without the Gauges. The precision of a machine component is one of the most important factors that decide the mechanical advantage and well as the efficiency of the machine component.

Due to this reason, proper knowledge about Gauges should be gathered by engineers before making a machine component. Working of a lathe, milling, grinding or other metal forming process cannot be made within the tolerance limit and without measuring their error.

In regards to this, Gauges plays a vital role. The above description is very brief, that just occupies the types and its descriptions. Hence, some gaps exist in this assessment. Although, if an engineer wants to seek knowledge on Gauges this assessment can be a fruitful one.


Dial Indicator

Reference (External Links):

  • Metrology Prof. Dr. Kanakuppi Sadashivappa Department of Industrial and Production Engineering Bapuji Institute of Engineering and Technology-Davangere

Media Credits:

  • Dial Indicator: By Lucasbosch – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=34769961
  • Slip Gauge Box: By Speedy1910 – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=81800683
  • Plug Gauge: By Glenn McKechnie – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=96026
  • Pin Gauge Collection: By Blue tooth7 – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=16971687
  • Snap Gauge: By Tom8442 – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=25039110
  • Vernier Calliper GIF: By Lookang many thanks to Fu-Kwun Hwang and author of Easy Java Simulation = Francisco Esquembre – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=15912813
  • Feature Image: Modified by Author
  • Image 1 (3D, Go, No-Go): Made by Author
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Saswata Baksi

Saswata Baksi is an Executive editor of Learn Mechanical. He has a background in Core Mechanical Engineering. In addition to overseeing Learn Mechanical's editorial strategy and managing contributions from a team of 5+ writers, he also writes articles about Manufacturing, Metal Cutting, Thermodynamics, Automobile.

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