Thursday, June 01, 2006

Dial Vernier Calipers

Dial Calipers is an advanced version of vernier calipers. In dial calipers vernier scale is replaced with a dial with a needle rotating in 360 degrees as you move the movable jaw of the dial caliper. The motion of the dial needle is achieved accurately by using precisely manufactured rack and pinion mechanism. The dial caliper eliminated the difficulty in reading the vernier scale especially one with small least count. Dial caliper also eliminated the parallax error which can occur from reading a normal vernier calipers with vernier scale.

Dial Vernier Caliper
Picture of Dial Calipers

Friday, May 26, 2006

Accuracy of Vernier Calipers

Accuracy of a vernier caliper depends upon the least count of the vernier. It is the smallest division which can be measured measured using vernier. When you measure an object using vernier calipers the resultant reading is the sum of main scale reading plus the vernier scale reading. Hence the accuracy of a vernier calipers mainly depends upon the least count of a vernier scale.

Monday, May 22, 2006

Parts of a Vernier Caliper

Let us examine the construction of a vernier caliper. A simple vernier caliper will have a fixed jaw with main sclae, movable jaw with vernier scale and locaking screw. Apart from the main external jaws which is used for measuring, there are also internal jaws which are used for measuring internal dimensions of holes and cavities and a depth measuring bar. See the picture of Vernier Calipers here.
The unique construction of vernier calipers makes it very versatile to measure almost all kinds dimensions of a work piece. A vernier caliper can be used for measuring external dimensions like length, width, thickness and outseide diameters of round work pieces. It can be used for measuring internal diameters of holes, length and width of cavities using the internal jaws. And with the help of depth measuring bars, we can also measure the depth of blind pockets etc using a vernier caliper.

Sunday, May 21, 2006

Picture of Vernier Calipers

Vernier Calipers comes in different shapes and sizes from different manufacturers. Here is a picture of a simple vernier calipers with fine adjustment which is most widely used in metal working industry.
Vernier Calipers

Saturday, May 20, 2006

History of Vernier Calipers

Here is a breif history about vernier scale used in vernier calipers. The concept of vernier scale was invented by Portuguese mathematcian, Pedro Nunes. Hence vernier scale is also called as nonius at some parts of the world. But it was in 1931 the vernier scale took it's present shape. French mathematician Pierre Vernier invented the present form of Vernier calipers.

Saturday, May 06, 2006

Types of Calipers

Let's look more into the various types of calipers. As I mentioned before there are basically calipers measured for external dimensions and internal dimensions. Vernier Calipers is caliper with a vernier scale to enhance the ability of a caliper to measure precise dimensions. In today's market Vernier Calipers with dial and digital read out are commonly available. Based on this let's list out the various types of calipers and vernier calipers available.
  • Inside caliper
  • Outside caliper
  • Divider caliper
  • Vernier Calipers
  • Dial Vernier caliper
  • Digital Vernier caliper

Sunday, December 18, 2005


Calipers are the simplest tools used for measuring. When since and technology started its development the need for measuring equipments aslo araised. Calipers are one of the oldest form of measuring tools. Lots of developmenst have come since then and todays calipers are equipped with vernier scales to digital scales.

Type of Calipers

Broadly we can categorise calipers into two. Outside caliper and Inside caliper.
Outside caliper as its name implies used for measuring external dimensions. For example you can measure the length and width of a recatagular block using outside caliper.
Inside caliper on the other hand is used for measuring internal dimensions. Examples are, measuring slot widths, hole sizes etc.

Vernier Calipers

Vernier caliper is a measuring instrument derived from the principle of calipers. But unlike simple calipers, vernier calipers makes use of a vernier scale which is attached on the main scale of the vernier calipers to give a more accurate reading. We will discuss more about vernier calipers in the coming posts.