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A speed square, also known as a rafter square or layout square, is an indispensable tool for carpenters and do-it-yourself (DIY) enthusiasts alike. In fact, This Old House expert Tom Silva lists it as his favorite tool. Below, we’ll show you how this versatile instrument combines the functionality of multiple tools in one compact package, making it a must-have for various construction and woodworking projects.
What Is a Speed Square?
A speed square is a triangular-shaped tool typically made of metal or plastic. It features a 90-degree angle and a 45-degree angle, along with various markings and notches that serve multiple purposes.
- 90-degree angle for marking and checking right angles
- 45-degree angle for quick miter cuts
- Protractor scale for marking angles
- Scribing notches for easy line marking
- Ruler markings for measuring
- Pivot point for creating angled cuts
This multifunctional tool can be used as a protractor, try square, miter square, and line scriber, among other applications.
6 Essential Speed Square Uses
Here are six essential carpentry and construction uses for this handy tool.
- Straightedge guide for circular saw cuts
- Protractor for marking angled lines
- Stud layout tool for framing walls
- Scribing tool for marking layout lines
- Right angle checker for ensuring square corners
- Center finder for circular objects
1. Using a Speed Square as a Saw Guide
One of the most common uses for a speed square is as a guide for making straight cuts with a circular saw. This method creates an instant fence for your saw, allowing for accurate cuts anywhere on the job site.
- Mark your cutting line on the wood.
- Place the lipped edge of the speed square firmly against the edge of the board.
- Align the saw blade with your marked line.
- Rest the saw’s baseplate against the speed square’s edge.
- Keeping the square in place, guide the saw along the edge for a perfectly straight cut.
2. Marking Angles with a Speed Square
The speed square excels at marking angles from 0–90 degrees for various cuts. Silva demonstrates in the video how to use the tool as a protractor.
- Place the lipped edge of the square against the board’s edge.
- Pivot the square around the corner where the lip meets the board.
- Use the degree markings on the square to find your desired angle.
- Mark your line along the square’s edge at the chosen angle.
3. Laying Out Wall Studs
For framing projects, a speed square is invaluable for marking stud locations. Here’s how to use it:
- Hook the square’s lip on the edge of your bottom plate.
- Use the ruler markings to measure out your stud spacing (typically 16 inches on center).
- Mark your stud locations with an “X” where you want the studs to go.
- Use the square’s edge to draw a line across the plate for each stud location.
4. Using Scribing Notches
The speed square features several notches along its edges that serve as scribing guides. These notches are particularly useful for marking cut lines or layout lines quickly and accurately.
- Choose the appropriate notch based on the desired distance from the board’s edge.
- Place your pencil in the notch.
- Slide the square along the board’s edge, keeping it tight against the wood.
- This creates a perfectly straight line parallel to the edge at a specific distance.
5. Checking for Squareness
Ensuring that components are set at a perfect right angle is crucial in any construction or woodworking project. Here’s how to check for squareness using a speed square.
- Place the 90-degree angle of the square against the edge of the material.
- Align the material’s edge with the square.
- If the edges align perfectly, your material is square; if there are gaps, adjustments are needed.
6. Finding the Center of Circular Objects
While not mentioned in the video, a speed square can also help find the center of a circular object. Here’s how to use it:
- Place the square’s right angle against the circle’s edge.
- Use the square’s angled edge to draw a line across the circle.
- Rotate the square 90 degrees and repeat.
- The intersection of these two lines marks the circle’s center.
Creating a Custom Speed Square Holder
While you can use clips or purchase special holsters to keep your speed square on your belt, you can also make your own holder. Silva demonstrates how to create a custom holder for your speed square using PVC materials.
- Cut a PVC baluster to the appropriate length.
- Create a stopped slot along one side using a table saw or router.
- Cut a 3/4-inch-thick plywood strip to fit inside the PVC holder and secure it with short screws.
- Attach a metal belt clip to the opposite side of the holder.
Choosing the Right Speed Square
The essential features of a speed square are fairly standard, but you do have some choices to make.
Material Options
Speed squares come in various materials, including:
- Aluminum: Durable and lightweight, suitable for both professional and DIY use
- Steel: Extremely durable but heavier, ideal for heavy-duty projects
- Plastic: Lightweight and inexpensive, best for light to moderate use
Size Considerations
Speed squares typically come in two main sizes:
- 7-inch: The most common size, suitable for most general purposes
- 12-inch: Provides extra reach for larger projects and materials
Cost
Material and size are the biggest cost factors. Most speed squares cost between $10 and $20, but a 7-inch plastic model could cost as little as $5 and a 12-inch steel square as much as $25. More expensive speed squares may also have features like etched markings that won’t rub off over time and nonslip grips for easier handling.
Our Conclusion
A speed square is an incredibly versatile and essential tool for any carpenter or DIY enthusiast. Its multiple functions—from marking angles to guiding saw cuts—make it indispensable for many projects. By mastering the various uses of a speed square, you can significantly improve the accuracy and efficiency of your woodworking and construction tasks.
