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Tools The Bevel Protractor
Bevel Protractor
T
he bevel protractor is a type of protractor that is circular and has a pivoted
arm used for measuring and marking off angles. This type of protractor
is commonly used for architectural and mechanical purposes. Other types of protractors
include the basic protractor, circular protractor, and external protractor. The basic protractor is most commonly
used in school geometry classes for measuring angles up to 180 degrees. The circular protractor is used when
measuring angles up to 360 degrees. An external protractor is used for spheres, and commonly utilized by
astronomers. While these types of protractors are useful for basic angle measurements, the bevel protractor will
prove to be the most beneficial type in any design or construction project.
M
ost protractors are used to measure existing lines. However, they can also be used
to construct new lines. The bevel protractor consists of a beam,
graduated dial, a blade and a swivel plate that is attached by a thumb
nut and clamp. (figure 1). The blade moves to create lines with
arbitrary angles.To use the protractor, the clamp must be loosened
by turning it counterclockwise so that the blade can be easily rotated.
The blade swivels until the appropriate angle measurement is lined up.
When the blade is lined up correctly, rotate the clamp clockwise
to tighten it and ensure an exact measurement.
Figure 1
A
bevel protractor has a full circular scale that
is made up of 360 degrees. Unlike simpler
protractors that only provide degree measurements, a bevel protractor
also has a vernier scale (figure 2). One vernier is equal to 1/12 of a
degree, which provides a more accurate measurement. When drafting
a design, it is important to have precise measurements that will later
correspond to the final product. The main scale on a bevel protractor
has four 90-degree components.The vernier scale is divided into 24
increments, with 12 spaces on either side of the zero, as seen in figure
2.
T
Figure 2
he bevel protractor is commonly used by woodworkers who
need to make a more complex design with angles other than 45 and 90 degrees. Most circular table saws
provide a scale for cutting the correct angles. However, like a basic
protractor, the scale is not as small and exact; the lines are often
thick and difficult to match up with the wood. In order to achieve the
best results, marks can be made directly onto your building materials
using a bevel protractor, and then the saw can be used to cut along
the lines you have created. For large projects like building treehouses
and playgrounds, a bevel protractor is a wise investment. It will
assist in every stage of the buliding process from drafting to putting
on the final touches. In no time at all you will be able to design and
construct a unique place for your children to play, that is also safe.