The Vernier scale has 12 divisions on each side of the centre zero. (It means there are 24 divisions on the vernier scale) It is designed to allow the user to move the blade around, especially with a higher degree of accuracy, when trying to create the final alignment to measure the object.

The bevel protractor consists of a beam, a graduated dial, and a blade that is connected to a swivel plate (with Vernier scale) by a thumb nut and clamp. When the edges of the beam and blade are parallel, a small mark on the swivel plate coincides with the zero lines on the graduated dial.This is the base of the bevel protractor over which the other parts are present. The main scale or the dial scale is marked over this dial. Zero the protractor: Place the bevel protractor on a flat and level surface. Locate the zero adjustment screw or knob on the protractor and turn it until the indicator reads zero on the scale or digital display. This step ensures that the protractor is properly aligned and calibrated. A positioning goniometer or goniometric stage is a device that rotates an object precisely about a fixed axis in space. It is similar to a linear stage— however, rather than move linearly relative to its base, the stage platform rotates partially about a fixed axis above the mounting surface of the platform. Positioning goniometers typically use a worm drive with a partial worm wheel fixed to the underside of the stage platform meshing with a worm in the base. The worm gear may be rotated manually, or by a motor in automated positioning systems. To know the value of 'h', you need to know the value of 'θ' first and that can be solved by using Bevel Protractor.

In the case of other types of precision protractors, such as bevel protractors and digital protractors, it is suggested to send such protractors to a traceable calibration laboratory. How Often Do Protractors Need Calibration?

Read Also: Vernier Caliper: Parts, Types, Working Principle, Least Count, Errors Parts of a Bevel Protractor A bevel protractor consists of several key components that enable precise angle measurement. Understanding these components is essential for effectively using the tool. Let’s take a closer look at each component: