eduphysics
CBSE AND NEET

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INTRODUCTION

Screw gauges are precision measuring devices that are widely used in engineering, manufacturing, laboratories, and research to precisely measure linear distances, wire radius, and glass plate thickness, among other things.

To get correct readings, common errors like zero error, least count error, and parallax error must be addressed.While concentrating on the measurement, keep the screw gauge’s errors to a least.In this part, we will look at screw gauge formula and the applications of a screw gauge in various fields. 

SCREW GAUGE IMAGE

 

CONSTRUCTION – MAIN PARTS OF A SCREW GAUGE

Frame

Frame is U-shaped fitted with a screwed spindle which is attached to a thimble.

Anvil

The smaller stud is known as the anvil. The anvil is the fixed part of the device.

Spindle

The longer stud is known as the spindle. The spindle moves as and when the head is moved. The object to be measured is held between the anvil and the spindle.

Sleeve

The Barrel or sleeve is connecting the frame to the cylindrical tube. It is a non-movable part of the screw gauge and has a scale inscribed over it which is the main scale of the device.

Thimble

The thimble carries the Vernier or secondary also called the circular scale.

Ratchet

It is a limiting device which applies a pressure by slipping at a predetermined torque and thus prevents the spindle from moving further.

SCREW GAUGE – USES

Diameter and thickness

A screw gauge is used for measuring accurately the diameter of a thin wire or the thickness of a metal sheet. It can also be used to measure the thickness of a paper.

Mechanical engineering and Machining

A screw gauge is used for the correct measurement of components in mechanical engineering and machining.

Micrometer, sometimes called micrometer screw gauge is also used in telescopes or microscopes to measure the clear diameter of celestial bodies or microscopic objects.

Measuring the gauge

It is named as screw gauge, because it is used to measure the gauge of a metal sheet or a wire. The gauge number of a wire or metal sheet can also be verified.

Construction industry

In the construction industry, it is used to measure the diameter of the steel rod, which is used in the construction of building.

Micrometer screw gauge

A micrometer is the type of gauge,that gives the precise measurement of small distances.Calibration checks the precision of the measuring instrument and determines how far the measurement can be relied upon.

SCREW GAUGE -FORMULA

Pitch of the screw gauge

Pitch is the linear distance traveled by the screw head in a successful rotation of the screw.

                                                                     (OR)

Pitch is the axial distance between threads and the distance the thread moves with 360-degree revolution.In most cases, it turns out that the pitch is 1 mm.

While rotating the thimble, the spindle advances towards the anvil. Give the thimble seven complete rotations, that is move the circular scale by 100 calibrations seven times and note the distance moved in the pitch scale.

 

Least count of the screw gauge

Diameter and Radius of the given wire

SCREW GAUGE -ZERO ERROR

 Zero error in screw gauge

Positive error in screw gauge

 

Negative error in screw gauge

Minimizing zero error

• Select a screw gauge that is in good condition.
• Make sure that screw gauge is clean and free of dirt.
• While taking the measurement, hold the screw gauge firmly and steadily.
• Avoid using too much force while rotating the screw.
• For correct measurement take multiple reading and take average out of it.

SCREW GAUGE NUMERICAL

SCREW GAUGE NUMERICAL -1

The main scale of a screw gauge has 1/2 mm mark for complete rotation the screw advances by 1/2 mm.Read the screw gauge in which the markings are shown below.

 

SCREW GAUGE NUMERICAL -2

Read the normal screw gauge in which the main scale has 1/2 mm mark.In complete rotation the screw advances by 1/2 mm and the circular scale has 50 divisions.

 

 

SCREW GAUGE NUMERICAL -3

In a screw gauge, five complete rotations of the screw gauge cause it to move a linear distance of 0.25 cm.There are 100 circular scale divisions.The thickness of the wire measured by this screw gauge gives a reading of four main scale divisions and 30 circular scale divisions.Assuming negligible zero error.find the thickness of the wire.

SCREW GAUGE NUMERICAL SOLUTION

SCREW GAUGE NUMERICAL-4

Read the normal screw gauge in which the main scale has 1/2 mm mark.In complete rotation the screw advances by 1/2 mm and the circular scale has 50 divisions.

 

CONCLUSION

Screw gauges are a correct, precise, and adaptable instrument that plays an important part in their precision and dependability as a measuring item for a wide range of things. Users of screw gauges can do more precise measurements and assure the trustworthiness of their results with a basic grasp of zero error, zero correction, and formula.

Screw gauges are a must-have tool for engineers, machinists, and quality control personnel.Because of its vast application in a variety of sectors, the screw gauge remains a vital tool for precise measurements, contributing to the growth of science, engineering, and technology.

LINK TO NEET PHYSICS :Screw Gauge Practice Questions

Link to least count of a screw gauge

QUESTIONS

• What is the pitch of the screw?
• What is the least count of a screw gauge?
• What is zero error and zero correction in a screw gauge?
• What is the total reading in a screw gauge?