**Vernier Caliper Classification and Types**

Vernier Caliper is used to measure wide variety of lateral dimensions like lengths, depths, widths, breadths and diameters of machine parts and objects up to accuracy of 0.1 mm in case of metric scale and 1/1000(0.001) of an inch if there is inches scale is engraved on a Vernier Caliper.

Now days so many variety of Vernier Caliper is available for industrial use in different demanding situations like linear lengths and bore depths.

Vernier Caliper can be classified in different types in many ways, here are some of those.

**1.Classification by construction /nature of measurements.**

**2.Classification according to scale type.**

**3.Classification by output reading indication.**

**4.Classification according to relation between main scale and Vernier scale**

Let’s have a look at micrometer types one by one; those are falling in above mentioned categories.

**1. Classification by construction /nature of measurements.**

Before moving forward to Vernier caliper types in this classification, it is necessary to know that what Vernier caliper is!

For this purpose you can read article Vernier caliper, it covers basics of Vernier caliper theory like parts, functions and its use. Perhaps there are five types of Vernier caliper which are vastly using in mechanical workshops and industry.

- Plain Vernier Caliper
- Combination Vernier caliper
- Vernier height gauge
- Vernier depth gauge
- Special purpose Vernier Caliper

**Plain Vernier Caliper:**

It is used to take basic length, width and diametric measurements to accuracy up to 0.05mm or 0.001 inches.

**Combination Vernier caliper:**

Its basic structure is like plain Vernier only addition is a sliding bar with Vernier scale which makes it able to take the depth and height measurements along with length, width and diametric values.

Its shape is specially designed to measure heights of work pieces and objects.

**Vernier depth gauge:**

This type of Vernier caliper is only designed to take depth measurements to higher degree of accuracy.

**Special purpose Vernier Caliper:**

All of above types cannot cover all measurement requirements of workshop and industry in some cases we cannot use any of above so here comes the need of special purpose Vernier caliper which may be available market or specially be designed for a specific requirement.

**2.Classifications of Vernier caliper according to scale type are:**

- Metric vernier caliper
- English Vernier caliper
- Combination scale Vernier caliper

** Metric Scale Vernier caliper:**

A Vernier caliper that measures and shows its reading in SI system of units only, reading its values mostly in millimetres and a fraction of it i.e. 0.1mm (least count). It can indicate output values in centimetres also.

**Imperial scale Vernier caliper:**

A Vernier caliper that measures and shows its reading in Imperial system of units only, reading its values mostly in inches and a fraction of it i.e. 0.01 inches (least count).

** Combination scale Vernier caliper:**

Vernier caliper is normally provided with both imperial and metric scales on it and can measure and show its reading in both cm/mm and inches at same time, it’s called combination Vernier caliper in terms of scale type.

**3. Classification by output reading indication.**

There are three types of Vernier caliper according to ways it shows measured value’s reading.

**1. Analog Vernier caliper:**

Values can be obtained by scale engraved on Vernier caliper by reading and calculating it properly.

**2. Dial Vernier caliper:**

Shows Vernier scale reading on a dial provided with Vernier scale.

**3. Electronic display Vernier caliper:**

Shows reading on LCD screen, now days comes with both inches and metric measuring modes.

**4. Classification according to relation between main scale and Vernier scale**

There are two types of Vernier caliper falls in this category:

- Forward Vernier
- Backward Vernier

**Forward Vernier:**

Vernier scale is a small scale graduated in specific relation with main scale. For example let us say in metric calipers main scale has graduation in millimetre minimum of 1 mm line. Vernier scale graduated in 10 divisions its means that the space of 9 mm is divided into ten equal parts it shows ten Vernier scale divisions are equal to 9 main scale divisions, so the value of 1 Vernier scale division is less than the value of 1 main scale division this type is called forward Vernier so we can say one liner:

Vernier scale having one Vernier scale division value lesser than one main scale division value, is called forward Vernier**.**

**Backward Vernier:**

As explained above let suppose same metric main scale having minimum division of 1 mm and on Vernier scale space of 11 mm is divided into ten equal parts which shows 10 Vernier scale divisions are equal to 11 main scale divisions and it means one Vernier scale division value is greater than one main scale division this type of Vernier scale is called backward Vernier.

Vernier scale having one Vernier scale division value greater than one main scale division value is called backward Vernier.