How to Measure and Cut 45-Degree Angles With a Table Saw

Updated July 20, 2017

Many carpentry projects require the ability to create an accurate 45-degree angle. This is useful in creating joints and forming edge or finishing pieces. Cutting a 45-degree angle on a table saw is made easier by the built-in mitre gauge on the saw surface. This gauge can be rotated and set to specific angles. With the help of a few additional tools, making a 45-degree angle cut requires only basic woodworking knowledge.

Hold one edge of the drafting triangle against the saw blade. Loosen the handle of the mitre gauge by twisting it counterclockwise. Set the edge of the mitre gauge against the angled side of the drafting triangle. Tighten the mitre gauge handle.

Screw the 10-inch piece of wood to the pre-made holes on the mitre gauge. The end of the wood should extend past the saw blade. This will create an angle guide for the end product.

Start the table saw. Push the guide through the saw to cut off any overhanging wood. Turn off the table saw.

Mark the start location of the cut on the piece of wood to be cut. Hold the wood tight against the guide and line up the mark with the saw blade. Start the saw and push the wood through using the guide. Turn off the saw.


If a precise angle is important, cut two test pieces of wood and then check if the cut ends line up perfectly to form a right angle. If not, adjust the mitre gauge slightly and try again. If the wood extends past the end of the cutting surface, a tall piece of scrap lumber should be used to support the wood as the cut is being made to make the cut accurate. Account for the width of the blade before making any measurements.


Table saws should only be turned on while actively making a cut, and should be turned off before reaching for anything near the saw blade.

Things You'll Need

  • 45-degree drafting triangle
  • 10-inch rectangular piece of wood
  • Woodworking screws
  • Power drill
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About the Author

Ryan Anderson began writing professionally in 2010, focusing on home improvement and business. He is currently a senior at a small liberal arts college in the Northwest. He is majoring in business and international economics and will be graduating in the spring of 2011.