Main Difference – Vernier Caliper vs. Micrometer
Vernier calipers (vernier callipers) and Micrometers (Micrometer screw gauges) are both used to measure distances too small to be measured using a metre rule with a least count of 1 mm. The main difference between vernier caliper and micrometer is that the vernier caliper uses two sliding scales with different spacings between markings on each scale while a micrometer makes use of a screw to translate small distances moved by its jaws to larger distances along the marked scale.
What is a Vernier Caliper, How to Read a Vernier Caliper
A vernier caliper consists of a sliding scale which is divided such that the distance between two marks on this scale is smaller than the distance between two marks on the main scale. To measure an object, the object is kept between the jaws and the vernier scale is moved. By looking at which mark on the vernier scale lines up with a mark on the main scale, the distance between the jaws could be read off to a higher precision than the least count of the main scale. For more details on how to read a vernier caliper, refer to the video posted below.
Typically, vernier calipers can measure lengths to a precision of 0.1 or 0.05 mm. Most vernier calipers are equipped with a set of smaller jaws for measuring internal diameters and a depth probe to measure depths. Digital vernier calipers come with a small display that shows the value directly, and their accuracy could be as high as 0.01 mm.
The diagram below shows a standard analogue set of vernier calipers. Specifically, note the numbered parts (1) outside jaws, (2) inside jaws, (3) depth probe, (4) main scale and (6) the vernier scale.
What is a Micrometer
In a micrometer, the object to be measured is placed between the jaws and the thimble is rotated until the jaws move together and clasp the object. A screw attached to the thimble rotates along with it and allows for precise values of distances to be read off from the scale. The video posted below explains how to read a micrometer.
A typical micrometer has a precision of 0.01 mm. For measuring inner diameters and depths, different types of micrometer are used.
The diagram below shows, from bottom to top an outside micrometer, an inside micrometer and a depth micrometer (note that these particular micrometers have been calibrated for the imperial system).
The video below explains how to read vernier calipers as well as micrometers:
It is important to remember that both micrometers and vernier calipers can give zero errors. Before measuring an object, it is always good practice to put the two jaws together and see whether the instrument gives a reading of 0. If this is not the case, the reading should be noted and should be added/subtracted to the measurement of the object.
What is the difference between Vernier Caliper and Micrometer
Working Principle of Vernier Caliper and Micrometer
Vernier calipers use a sliding vernier scale to measure small movements of its jaws.
Micrometers use a screw to amplify small movements of its jaws to larger movements of the rotating scale.
Vernier calipers typically allow a user to measure external diameters, internal diameters as well as depths.
Micrometers usually only allow users to measure external diameters. Other, more specialized types of micrometers are available for measuring internal diameters and depths.
Vernier Calipers traditionally have a precision of 0.1 or 0.05 mm. Digital vernier calipers have a precision of 0.01 mm.
Micrometers typically have a precision of 0.01 mm.