Micrometer

A micrometer is an engineering tool used to measure linear dimensions such as thickness, diameter and lengths. It comprises a C-shaped frame with an adjustable jaw operated by an integral screw. 

Some micrometer models can measure objects as small as one μm. One can determine the fineness of measurement from the lead of the screw. Thus, the measurement accuracy depends on the screw-nut combination accuracy. 

A micrometer works on Abbe’s principle, unlike other hand callipers. Besides depending on the measurement applications, there are various micrometers such as bore micrometers, tube micrometers, depth micrometers and inside micrometers. The measurement range of micrometers varies every 25 mm and depends on the frame size. Thus, a micrometer should match the target for the right results.

Which Scientist Invented Micrometer?

Measuring objects dates back to 5000 years ago when the Egyptians built pyramids. In the 17th century, people used threads to measure the length of an object. 

In 1638, English astronomer W. Gascoigne used the thread principle to measure the distance between stars. He measured the distance of stars at night by finely adjusting the screw threads of his telescope. 

In 1639, he invented a measuring gauge called a “Calliper Micrometer.” His micrometer system comprised a rotating handle attached to the threaded rod’s end hooked to a portable jaw. The revolution of the handle against the disc gave the readings. 

Thus, the answer to the question: “which scientist invented micrometer” is W. Gascoigne.

Components Of A Micrometer

To understand the working of a micrometer, let us first know the tool’s key components. Then, component analysis will further help understand the reading of a micrometer. 

Anvil

The shiny component of the micrometer is Anvil. It ensures the spindle drifts towards the firmly secured object. It stays in constant contact with the part. If the Anvil has not been cared for properly, it can chip. Good quality Micrometers have carbide-tipped Anvils that provide an extended tool life.

Spindle

The spindle is located beside the measuring faces. It is projected towards the Anvil because of its direct contact with the thimble.

Locking Nut

A nut for locking is a valuable component and ensures awareness of the measurement and clamping of the spindle for small lot gauging. Some micrometers have complete lock nuts, while some have lock levers. The locking lever variety is primarily used because of relative ease in maintenance and use.

Sleeve or Barrel

The micrometre barrel features a linear scale and is kept securely in place. One can also find vernier markings on this part of the micrometer. The scale on the barrel allows high precision measurements in degrees of 0.0001.

Frame

Frames in a micrometer are C-shaped. They ensure optimum positioning of the barrel and Anvil. Depending on the micrometer’s desired functioning, frames take a variety of sizes and shapes. For example, a hub-shaped frame is ideal for highly accurate measurement readings in confined spaces. 

Thimble

The thimble comprises graduated markings that are easy to read. You can turn it by applying gentle pressure from the thumb.

Ratchet Stop

The ratchet stop is found at the end of the handles of a micrometer. It restricts the pressure amount by enabling movement at a calibrated torque.

Working Of Micrometer

A micrometer consists of a screw or thread calibrated and placed inside the spindle. It allows for high levels of accuracy in the device’s measurement capabilities. 

The micrometer screw is used to converse minor distances for measurements. The spindle moves by turning the thimble or ratchet knob until a light contact occurs between the Anvil and spindle. Every round (360°) turn of the spindle adjusts the space in between the measures to display by 0.025 inches in imperial and 0.05 in metric.

The needle’s thread pitch directly bears the measuring precision level. The measuring object is positioned between the spindle and the Anvil. The spindle gets machine-screwed at a great accuracy level. Differential screws are used in certain micrometers for high accuracy levels.

The stability of the object to be measured is essential. Therefore, the object must be in parallelism to the Anvils. Also, a constant pressure level must be applied while measuring.

The integrated ratchet thimble ensures functions as an integrated torque wrench and provides a high accuracy level of measurements. You should continue the process of turning the ratchet handle till you hear a repeated clicking. Then, it assures measures with constant torque level. 

Digital micrometers have electrical circuits that allow digital measurements and highly accurate readings. In addition, the measurements are displayed on the LCD screens.

Uses Of Micrometer

Precise measurements are the primary uses of micrometers. Besides, other uses of a micrometer are as follows:

• Parts of machines that move close to each other must be measured using a micrometer. For example, a piston moves in and out of a cylinder and hence needs to remain steady in a straight line or else it can wear the cylinder.

• The pipe fittings and bearings must be measured precisely for optimal functioning. 

• The thickness of items such as metals is measured using a micrometer.

Conclusion

A micrometer is a measuring tool used for measuring linear measurements. One of the primary uses of micrometer is to measure the dimensions of objects that require high precision measurements. Tool manufacturing industries use micrometers for precise measurements of their tools. A micrometer is thus a measurement instrument that gives accurate measurements of small objects.