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How To Use Miter Saw Protractor – Best Ways [With Pictures]

Miter saw protractor helps the carpenters or DIYers to achieve accurate cutting angles. But the problem comes with using. If you don’t know how to use a miter saw protractor, chances are high that you will end up getting the wrong cut.

This device is constructed with two arms and two individual scales. The inner scale gives the reading of the miter cut. Similarly, the outer scale is used to get a reading of the single cut. It’s all about positioning them correctly and collecting data.

However, this device can be your great company in crown molding. You can also use this device to determine if the edge of a box is perfectly square-shaped. Once you find the angles, the rest you have to do is a perfect fit for perfect cutting.

How does a miter saw protractor work?

Miter saw protractor is a device to measure the angle of the inner and outer corners for installing molding. Without various cutting angles, it’s difficult to perform versatile implementations with a miter saw. However, its various structural parts help in measuring the cutting angles. Let’s know about them.

Miter saw protractor arms

A miter saw protractor has two arms with individual longitudinal axes. They have a proximal and distal end which are joined by a pivot. Each arm of a miter saw can rotate about its longitudinal axis.

The arms are opened to fit around most of the cutting angles. Therefore, the change in each arm’s angular relation between its respective proximal and distal occurs. This device comes with an O-ring which helps the arms to rotate freely.

Inner scale

There is a circular measuring scale with every miter saw,, which has an arrow. The arrow rotates accordingly and shows the correct measurement when the arms are rotated. An outer arrow will indicate inside the internal scale, and the reading is considered a “miter cut.” The inner scale of a miter saw protractor can rotate up to 90 degrees in a clockwise and anticlockwise direction.

Outer scale

There is another cut in the miter saw protractor called “single cut”. Its measuring principle is the opposite of the miter cut. That means it’s the inner arrow which indicates the outer scale’s reading. The outer scale also measures up to 90 degrees in both directions.

No matter you position the miter saw protractor upside down or backward, the result will be accurate. After adjusting the settings on your miter saw, you can correspond with the measured angles. And finally, you can generate versatile types of cuts.

How to use miter saw protractor for crown molding

Crown molding projects require finding the perfect angle. Follow these steps to get an enchanting output.

Step:1- Determining the wall angle

  • Place a tee bevel in the inside or outside corner of the wall. It’ll help you in finding the wall angle.
  • After that, place your tee bevel on the saw set tool.

Step:2- Cutting crown molding

Way:1- Cut off the fence

  • Set the degree to cut in the desired angle you observed before on your saw.
  • Place the molding with a small cove on the upper portion of the fence.
  • Start your saw to cut the fence. The process will be ended up within a few seconds.

Way:2- Cut on the flat

  • The first step of cutting the crown will be on the fly position. It’s convenient to determine the spring.
  • Take a sample over crown molding. Place it up against the guide. You can hold it up on 38 and line up over the 45 for a perfect fit.
  • Once you determine the crown molding spring, take the bevel to line it up. Also, reference it using the guide.
  • Now, find the correct table settings and adjust them with the remover setting.
  • Finally, set the vertical setting and then start cutting after the perfect fit.

How to use a protractor for miter cuts

Let’s see how to use a protractor for miter cuts.

Step:1- Determining the external angle

  • Find the upper arm of the miter saw protractor first.
  • Then, hold the upper arm and pull the bottom arm simultaneously away. The turn should not exceed ¼ unit. There will be an angle of approximately 90 degrees between the hold scale and the bottom arm.
  • Now, place the inner portion of the protractor around the corner. Ensure that each arm is flush against the sides of the corner.

Step:2- Finding the internal angle

  • To measure the internal angle, hold the upper arm still as similar to the previous step.
  • Then, the other arm should perform a ¾ turn while the first arm is holding strictly.
  • Now, place the miter saw protractor in the internal corner and spread both arms. The arms should flush with the sides of each corner.

Step:3- Perform cutting

  • Once you know the desired angle, it’s all about positioning your miter saw. And finally, cut with the determined angle.

How to use a miter saw protractor in a box

Miter saw protractor can be used in a box to check if its edges are perfectly square. Here you know about the detailed process.

Step:1- Place the protractor precisely

  • Start by opening the protractor arms. Position them at a 180-degree angle.
  • Now, push the protractor firmly up against the edge of the box.
  • Take the single-cut scale reading at this moment. It should be 90 degrees.

Step:2- Observing the angle

  • After placing the miter saw protractor against the edge, look for gaps. If the single cut arrow indicates 90 degrees, then the box is square.
  • In case you are using a combination protractor, use the protractor located on the rear side. The actual protractor reading would then be around 180 degrees.
  • If the shape isn’t perfectly square, then the single-cut scale reads 90 degrees.
  • In the case of the combination protractor, the reading will be 180 degrees. Also, there will be a gap between the protractor and the measuring edge of the box.

See Also- How Many Amps Does A Miter Saw Use

How to use a miter saw protractor in a building

Miter saw protractor is used to determine the internal angle inside a building. The process is pretty simple. Let’s have a look at the steps.

  • Fix a corner of the building first. Place the protractor with the scale facing upwards. After removing the protractor from the edge, the arms won’t lose their position. The reason behind this mechanism is tension in the pivot point.
  • It’s time to hold the top arm still in position.
  • The other arm should perform a ¾ turn. In that time, if you move the first arm, the positioning will be dismissed.
  • Finally, place the miter saw protractor in the internal corner and spread both arms. The arms should flush with the sides of each corner. Then, you get the desired angle.

Read Also:- Best Miter Saw Protractor for woodworking


Miter saw protractor is a complicated device unless you know its function properly. Before knowing how to use a miter saw protractor, you should know about its working principle. You should start by knowing their arms, the movement procedure of the arms, and their measuring system.

The hard part is determining the internal angle, as well as the external angle. If you don’t pull the top arm of the protractor steadily, the result might be faulty. Also, the other angle should be moved carefully up to the depicted limit.

If you’re in a crown molding project, you have two different ways to perform the cutting. Before that, carefully determine the wall angle for the best result. Whatever your project, once you get used to this device, it’s nothing but technical work.

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