Page 73 - CITS - Fitter - Trade Theory

FITTER - CITS

Vernier bevel protector

• Introduction of vernier bevel protector
The Vernier bevel protector is a precision instrument commonly used in various technical and mechanical fields,
particularly in woodworking, metalworking, and engineering. It is designed to accurately measure and set angles,
ensuring precise cutting, machining, or joining of materials.
This tool is named after the Vernier scale, a graduated scale invented by Pierre Vernier in the 17th century, which
allows for highly accurate measurements. The bevel protector incorporates this Vernier scale mechanism along
with a bevel protractor, creating a versatile device for angle measurement and adjustment.
The Vernier bevel protector typically consists of a protractor base with a pivoting arm that holds a blade or a
reference surface. The protractor base is marked with angular graduations, usually in degrees, allowing users
to set and measure angles with precision. The pivoting arm can be locked into position at a desired angle using
clamps or screws.
• Parts of vernier bevel protector
The Vernier bevel protector typically consists of several key parts that work together to facilitate accurate angle
measurement and adjustment. These parts may vary slightly depending on the specific design and manufacturer,
but the following are common components found in most Vernier bevel protectors:

1 Protractor base: The main body of the tool, usually made of metal or durable plastic, which serves as the
foundation for angle measurement. It features a graduated scale marked with angular divisions, often in
degrees, allowing users to read the angle being measured.

2 Vernier scale: A secondary scale that enhances the precision of angle measurement. The Vernier scale is
typically located adjacent to the main scale and consists of finer divisions than the main scale. It enables users
to make more accurate readings by aligning the Vernier scale with the closest marking on the main scale.
3 Pivoting arm: A movable arm or blade attached to the protractor base, allowing for the adjustment of angles.
The arm can usually be locked into position at a desired angle using clamps, screws, or other securing
mechanisms.
4 Locking mechanism: A mechanism, such as a screw or clamp, that secures the pivoting arm in place once
the desired angle is set. This prevents unintentional movement and ensures the accuracy of the measurement.
5 Reference surface or blade: The part of the pivoting arm that contacts the workpiece or serves as a reference
point for angle measurement. It may be a flat surface or a blade-like structure, depending on the specific
application and design of the Vernier bevel protector.
6 Magnifying lens: Some Vernier bevel protectors feature a magnifying lens or loupe to aid in reading the
Vernier scale more accurately, especially when measuring very small angles or fractions of a degree.
• Least count of vernier bevel protector

The least count of a Vernier bevel protector refers to the smallest angle that can be accurately measured using
the device. It is determined by the graduations on both the main scale and the Vernier scale, and it represents the
difference between one division on the main scale and one division on the Vernier scale.
To calculate the least count of a Vernier bevel protector, you need to know the number of divisions on the main
scale (N) and the number of divisions on the Vernier scale (V). The formula for calculating the least count (LC) is:
LC = (Value of one division on main scale) - (Value of one division on Vernier scale)

58

CITS : CG & M - Fitter - Lesson 10