Short Answer:

In mechanical workshops, different types of measuring instruments are used to check size, shape, and accuracy of machined parts. These instruments help ensure that each part meets the required dimensions and fits properly during assembly. Measuring tools can be simple hand tools or more precise instruments depending on the need.

Common types include steel rulers, vernier calipers, micrometers, height gauges, dial indicators, bevel protractors, and surface plates. Each tool is designed for specific purposes like measuring length, diameter, thickness, depth, angle, or flatness with proper accuracy.

Detailed Explanation:

Different types of measuring instruments used in workshops

In mechanical engineering and manufacturing, accurate measurement is very important. A small error in dimension can lead to improper fitting, machine failure, or product rejection. That is why mechanical workshops use various types of measuring instruments to inspect and control dimensions during and after machining.

These instruments are used to measure length, diameter, thickness, depth, angle, and surface quality. Some are used for basic checks, while others are designed for high precision work.

Let’s explore the most commonly used measuring instruments in workshops:

1. Steel Rule

A steel rule is the most basic and commonly used measuring tool. It is a straight metal strip with markings in millimeters and inches.

• Used to measure lengths or widths
• Easy to use but not highly precise
• Common in fitting, marking, or rough layout work

2. Vernier Caliper

A vernier caliper is a precision tool used to measure internal, external, and depth dimensions.

• Can measure up to 0.02 mm accuracy
• Has main scale and vernier scale
• Available in analog and digital types
• Commonly used in workshops for general accurate measurements

3. Micrometer

A micrometer is used for very precise measurement of small dimensions like shaft diameter or plate thickness.

Types include:

• Outside micrometer (external dimensions)
• Inside micrometer (internal diameter)
• Depth micrometer (depth of holes or slots)
• Accuracy: up to 0.01 mm
• Used where high precision is required

4. Height Gauge

A height gauge is used to measure the height of components or to mark lines parallel to a surface.

• Used on surface plates
• Can have vernier, dial, or digital reading
• Ensures accurate marking or checking of heights

5. Dial Indicator

A dial indicator is used to check runout, alignment, and flatness of a surface or part.

• Measures small movement or displacement
• Commonly used to check part accuracy in machines
• Works with magnetic stands for positioning

6. Bevel Protractor

A bevel protractor is used to measure angles between two surfaces.

• Has a protractor scale and swinging arm
• Can measure from 0° to 180°
• Used for layout and inspection of angular parts

7. Surface Plate

A surface plate provides a flat reference surface for measuring instruments.

• Made of cast iron or granite
• Used for checking flatness, squareness, and parallelism
• Base for height gauge, dial indicator, and inspection tasks

8. Combination Set

A combination set includes a ruler, square head, protractor head, and center head.

• Used for measuring angles, depth, and center of round jobs
• Versatile for workshop use and fitting tasks

9. Inside and Outside Calipers

These are simple tools used to compare sizes and check diameters.

• Inside caliper – for internal diameter
• Outside caliper – for external diameter
• Not very accurate but useful for quick comparison

10. Feeler Gauge

A feeler gauge is a set of thin metal strips of different thicknesses used to measure clearances or gaps.

• Used in engine work, machine assembly
• Checks gap between parts like valve and rocker arm

Conclusion

In mechanical workshops, various measuring instruments are used to ensure that all components are produced with the required accuracy and quality. Instruments like vernier calipers, micrometers, dial indicators, bevel protractors, and surface plates help check size, angle, and flatness with precision. Using the correct measuring tool not only improves product quality but also reduces errors and rework. Understanding each tool’s purpose is essential for effective workshop practice.