The L-shaped carpenter square (also known as a framing square) is one of the tools any do-it-yourself should have in his or her toolbox or hanging from a pegboard in the workshop. You'll get a lot of use out of it. Whether you use it as a simple way to make sure you're getting a true, perpendicular measure or to get a straight line while cutting down drywall, you'll find yourself reaching for it time and time again.
To start each project, you'll use it to check the wood edges cut at the factory. Just put the longer edge (known as the blade) of the carpenter's square over the outside edge of the piece of wood. Next, line up the shorter edge (known as the tongue). It should sit flush with the end of the wood. If it matches up on both at the same time, you're all squared away. If not, you'll have to make an adjustment cut to make it square.
The carpenter squares vary based on brand and length, mostly. On this site you'll find 7-inch ones and 24-inch squares. Sometimes it helps to have a small, medium and large one. Basic carpenter squares are really inexpensive, so you can easily afford more than one. A carpenter's square has measurements marked on the outside of the square and the inside, making measuring easier and more convenient.
Another square you'll want in your toolbox is the combination square. So how does a combination square come in handy? Well, let's say you're constructing a new dining room table. You could measure one end and mark it, then measure the other end and mark it before using a chalk line or a straightedge to connect the marks to make one long line. Or, you could just place the point of a pencil in the groove at the end of the combination square and slide it along the surface. It has a number of other uses, too. You can use it to set the height for bits and blades. You can also use a combination square when you need to calibrate the blade-tilt stops on your table saw. It has a bubble level and a scriber (a pointed pin) you can use to mark measurements. You can easily check to ensure the accuracy of angles. Plus, you'll know if the wood is level. With the combination square's 45-degree shoulder, you can check and lay out miters. Each time you use it you're saving time, which allows you to do more projects.
There's another type of square. It's the Speed square by Swanson. It's a roofer's best friend, and even comes in handy if you have to build stairs. It's a combination framing, tri, miter and protractor square. If fixing or replacing the roof of your home is on your honey-do list, you'll also love that the 7-inch pocket-sized Speed? square comes with a 62-page booklet with instructions, diagrams and tables you'll need to refer to as you construct a roof or stairs.
To help make sure you have accurate measurements and angles, in addition to level surfaces, when you're woodworking, Sears carries a number of laser levels, angle finders and other precision measuring tools from brands you know and trust, including Inca, Stanley, Swanson and Sterrett.