Sine bar

Construction and How to Use It

What is a Sine Bar?

A sine bar is a precision tool used in metrology for measuring angles with high accuracy. It consists of a hardened, precision ground body with two identical cylinders fixed at the ends. The distance between the centers of the cylinders is precisely controlled.

Construction of a Sine Bar

The construction of a sine bar involves the following components:

• Body: A flat, rectangular block made of high-quality steel or cast iron.
• Cylinders: Two precision-ground cylinders mounted on the body at a fixed distance apart.
• Surface Plates: Used as a reference plane when using the instrument.

How to Use a Sine Bar

Sine bars are commonly used in various industries that require precise angle measurements. In the machining industry, they are used to set the angle of milling heads, grinders, and other tools. In metalworking, they are used to measure the angles of saw blades, drill bits, and other cutting tools. In manufacturing, sine bars are used to align parts and machines accurately. Some of the applications of a sine bar are:

• Setting and Checking the Angle of Cutting Tools: In machining operations, it is essential to set the angle of cutting tools accurately to ensure the quality of the product. Itcan be used to set and check the angle of cutting tools such as milling cutters, drill bits, and lathe tools.
• Aligning Workpieces on Machine Tables: In machining operations, workpieces need to be aligned accurately on machine tables to ensure that they are cut or machined correctly.It can be used to align workpieces on machine tables, ensuring accurate machining and a high quality product.
• Measuring the Angle of Surfaces during Inspection: In industries such as aerospace and automotive, the accuracy of components is critical. It can be used to measure the angle of surfaces during inspection, ensuring that the components meet the required specifications.
• Measuring Angles in Research and Development: In research and development, accurate measurement of angles is essential to ensure the reliability and quality of products. It can be used to measure angles with a high degree of accuracy, ensuring that the products meet the required specifications.

To use a sine bar for measuring or setting an angle, follow these steps:

1. Place the Sine Bar on a Surface Plate: Ensure the surface plate is clean and free of debris.
2. Set the Desired Angle: Calculate the height of the gauge blocks needed based on the sine of the desired angle. The formula is: Height = Distance Between Cylinders × sin(Desired Angle)
3. Position Gauge Blocks: Place the calculated height of gauge blocks under one cylinder of the sine bar.
4. Verify the Setup: Use a dial indicator or spirit level to ensure the top surface is parallel to the desired angle.

Applications of a Sine Bar

Sine bars are widely used in industries for various applications, including:

• Setting up workpieces at precise angles during machining.
• Inspecting machined parts for angular accuracy.
• Calibrating other measuring instruments.

Conclusion

The sine bar is an essential tool for achieving accurate angular measurements in manufacturing and quality control processes. Its simplicity and reliability make it indispensable in many industrial settings.