How to Figure Angles in Woodworking

A protractor is an important device for determining angles.

Figuring out how to cut angles for woodworking is one subject, but another equally important matter is machine calibration. In the process of figuring out angles, it is critical to know that the machine used to cut them is accurate. This article will explain some of the simple techniques for calculating angles and how to apply them to woodworking. The basic way to figure angles is to use a pencil and a protractor, but just as technology has evolved, so have the methods for calculating angles in woodworking. Methods for finding angles have become much easier with the use of digital angle finders. These precision tools allow for quick calculation of otherwise difficult procedures for finding such angles. For this example, a simple square object will be used.

Things You'll Need

• Paper
• Pencil
• Engineer or architect triangle
• Engineer or architect scale
• Protractor
• Sliding T-bevel

Instructions

1. Draw a perfectly square object to scale on a sheet of paper using the architect scale, triangle and pencil.

2. Position the triangle diagonally from each corner of the square. Draw a line along the triangle, forming an X.

3. Extend one the four corners of the square 3 inches with the scale and pencil.

4. Place the 0 mark of the protractor on the extended line while centering it on the intersecting X lines of the drawn object.

5. Read the arched side of the protractor. This calculation is 45 degrees.

6. Adjust the sliding T-bevel to the angle on the drawing and transfer it to the saw or tool.

Tips & Warnings

• This method can be used to calculate any angle. The drawing can be any multi-sided object.

References

• Rockler Woodworking and Hardware: Understanding Angles

Resources

• Wood Bin Woodworking: Software To Calculate Cutting Angles