Screw Gauge Questions

We have seen many measuring devices in laboratories operated in various ways. The most common measuring devices are vernier callipers, scale, measuring tapes, and screw gauges. A screw gauge is also known as a micrometer screw gauge. Let us know about the screw gauge measurement using a micrometer. A screw gauge is an instrument used to measure a cylindrical or spherical object precisely. A screw gauge is a mechanical tool mainly used for accurately calculating the radius or diameter of a wire or the thickness of a thin metal sheet. It is primarily used in the mechanical field for measuring very small dimensions. It is used for calculating the thickness of small sheets like glass or plastics and the diameter of thin wires.

The main parts of the screw gauge are:

• Ratchet
• Sleeve
• Thimble
• Main scale
• Circular scale

Ratchet: It aids in moving the screw by turning it until the object is held between the stud and spindle of the screw.

Sleeve: It aids in marking the baseline and main scale

Thimble: Circular scale is marked using the thimble.

Main scale: It helps to read the length correctly up to 1mm.

Circular scale: It helps to read the length correctly up to 0.01mm.

Every rotation of the screw can correspond to an equivalent axial movement, known as the lead or pitch of the screw. When threads of the screw feature constant pitch, with known pitch value, the produced amount of axial movement can be traced on a scale easily. This is the principle used in measuring dimensions.

Steps to measure the reading:

• Clean the spindle and anvil.
• Place the object in between the spindle and anvil.
• Rotate the ratchet counter-clockwise to tighten.
• Tighten the spindle with the object in the midst.
• Lock the thimble while the object is in between.
• Take the object out cautiously.
• Before you unlock the spindle, note the reading.

The distance moved by the spindle per revolution gives the pitch of the screw gauge. It is calculated by moving the head scale over the pitch scale. Pitch is given by the formula:

Pitch of the screw gauge = (distance moved by a screw)/(no. of rotations given)

The distance moved by the tip of the screw when turned through one division of the head scale is known as the least count of the screw. The least count is given by the formula:

Least count (LC) of the screw gauge = (pitch)/(total no. of divisions on the circular scale)

Least count of micrometer screw gauge = (1 mm)/(100) = 0.01 mm

Important Screw Gauge Questions with Answers

1. Name five stationary parts of the screw gauge.

Some of the stationary parts of the screw gauge are Sleeve, Anvil, Spindle, Frame, and Thimble.

2. State true or false: The spindle cannot be moved if the thimble is locked.

1. TRUE
2. FALSE

Answer: b) FALSE

Explanation: To get the precise measurement, the spindle can be moved even if the thimble is locked.

3. What is a screw gauge?

A screw gauge is an instrument used for the precise measurement of a cylindrical or spherical object.

4. Fill in the blanks: Least count of micrometer is ____

1. 1mm
2. 2mm
3. 0.1 mm
4. 0.01mm

Answer: d) 0.01mm

Explanation:

5. Choose YES or NO: Are micrometers used in telescopes or microscopes?

1. YES
2. NO

Answer: a) YES

Explanation: Micrometers are used in microscopes or telescopes to calculate the diameter of celestial bodies or microscopic objects.

6. The C-shaped body that holds the anvil and barrel in screw gauge is known as _____

1. Sleeve
2. Anvil
3. Spindle
4. Frame

Answer: d) Frame

Explanation: The frame in the screw gauge is c-shaped thick, and heavy.

7. List five types of screw gauges.

Five types of screw gauges are:

• Universal micrometer sets
• Tube micrometers
• Blade micrometers
• Ball micrometers
• Bench micrometers

8. Choose YES or NO: Is the accuracy of the screw gauge affected if the device is scratched or shaken?

1. YES
2. NO

Answer: a) YES

9. Pitch is given by the formula: _____

1. Pitch of the screw gauge = (no. of rotations given)/(distance moved by a screw)
2. Pitch of the screw gauge = (no. of rotations given)-(distance moved by a screw)
3. Pitch of the screw gauge = (distance moved by a screw)/(no. of rotations given)
4. Pitch of the screw gauge = (distance moved by a screw)-(no. of rotations given)

Answer: c) Pitch of the screw gauge = (distance moved by a screw)/(no. of rotations given)

10. Which type of micrometer features a three-anvil head on a micrometer base and is used to measure inside diameters?.

1. Universal micrometer sets
2. Bore micrometers
3. Blade micrometers
4. Bench micrometers

Answer: b) Bore micrometers

Practice Questions

1. Explain bore micrometer.
2. What is a universal micrometer set?
3. List the uses of screw gauge.
4. What is the formula to find the least count of the screw gauge?
5. Explain the methods to use the micrometer.

Watch the video below to know about screw gauge.