How to Use a Combination Square

A combination square has interchangeable attachments that slide into place along the rule. They’ll help you check your accuracy on a number of tasks and projects. Here are a few tips for using one:

Step 1 The basics

A combination square includes a ruler with attachments that slide off and on. You can interchange attachments and tighten them down to use the square as a template for measurements and angle markings. For example, use it to mark right angles and check the accuracy of a saw cut.

Step 2 90 Degree Angle Edge - Tip 2

Mark continuous lines around 4 sides of a board or post,

Step 3 90 Degree Angle Edge - Tip 3

Use it as a depth gauge for measuring the depth of a groove.

Step 4 90 Degree Angle Edge - Tip 4

This edge is a handy way to set the depth of a router bit. It’s also great for recalibrating a table saw or miter saw blade.

Step 5 90 Degree Angle Edge - Tip 5

You can even scribe a line parallel to the edge of a board.

Step 6 45 Degree Angle Edge

Flip the 90 degree angle edge around to set it for 45 degree angle markings.

Step 7 The Protractor - Tip 1

Use this for marking specific angles. After setting the angle, tighten the attachment down and you have a template for repeating the same mark or cut on several pieces. This makes it good for decking or molding projects.

Step 8 The Protractor - Tip 2

This attachment is useful for finding the center of a dowel or rod.

Step 9 The Protractor - Tip 3

Find the center of large circular objects by marking two crossing lines. The center will be at their intersection.