# Use Of Angular Measurement Devices

Measurement devices or very important tools in manufacturing sites or in quality control departments. There are various kinds of measurement devices to measure different **geometrical features **such as eccentricity, linear measurements etc. One of these geometrical features that workpieces or specimens have angularity. Produced parts can have angular features to be measured with various devices. In this article we will explain these angular measurement devices.

## What Are The Angular Measurement Devices And How To Use Them?

Protractor device to measure angular features.

There are bunch of angular measurement devices and the most known one is Protractor. In Protractors, there is a fixed blade that is placed on the straight side of the measured part or specimen. There is a turning blade around the angular scaling ruler that is to be placed on the angular surface of teh specimen that is needed to be measured. You can read the angle value in different units(radians, degrees) from the angular ruler. The precision of protractor devices is moderate, but it is great for reading the angular measurements in a high speed.

Sine bar for measuring angularity in high precision.

Another high precision angular measurement device is Sine Bar. If we take a look at the working principle of Sine Bar, there is a two of rolls that attached to the sine bar itself. One of rolls placed onto the gage blocks that the ‘H’ value is read from them. Other roll is placed on the ground, and the bottom side of Sine Bar put on the surface that is needed to be measured. ‘L’ value is read which is the distance between the two of rolls. After that, the calculation of angle is very basic;

sin(A)=H/L

We can calculate the angle ‘A’ by calcularing the arcsin(H/L). And the calculation gives very high precision angular results.

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Source Of Images: Fundamentals Of Modern Manufacturing Book