How To Make a Circular Saw Guide

A circular saw is a versatile tool for any do-it-yourself enthusiast, but achieving perfectly straight cuts can be challenging without proper guidance. In the video above, This Old House’s Tom Silva and Kevin O’Connor demonstrate various methods for making straight cuts with a circular saw.

Creating a DIY circular saw guide is also a great option. This tool can act as a reference for multiple woodworking projects, helping you to achieve consistently straight, accurate cuts. Our guide walks you through how to create a circular saw guide to achieve precision in your work.

Creating a DIY Circular Saw Guide

Making a circular saw guide is an easy DIY project. You can customize this guide to your specific saw, providing consistent results across multiple projects. Below are the materials needed and step-by-step instructions.

Materials Needed

• Two pieces of 1/4-inch plywood (48 inches long)
• Wood glue
• Hot glue gun
• Circular saw
• Measuring tape
• Pencil
• Clamps

Step-by-Step Guide

Follow these steps to create your own circular saw guide:

1. Cut the base piece of plywood to about 12 inches wide.
2. Cut the fence piece to 3 inches wide.
3. Measure the offset of your saw blade from the edge of the baseplate.
4. Mark a line on the base piece that’s ½ inch more than your saw’s offset measurement.
5. Apply wood glue along this line and attach the fence piece.
6. Use hot glue to secure the fence in place while the wood glue dries.
7. Once dry, run your circular saw along the fence to trim the base to the exact width.
8. Flip the guide over and trim the other side, ensuring the saw’s baseplate is flush against the fence.
9. Optionally, add measurement marks along its length. Apply a clear finish over the marks to prevent them from wearing off over time.

Pro Tip: Norm Abram, master carpenter on This Old House, recommends making the guide from ½-inch scrap plywood: “Take a piece of plywood 7 inches wider than the saw’s sole and cut a 2-inch strip off the factory edge. The remaining piece is the base. Snap a line on the base 5 inches from the edge you cut, then glue and screw the strip facedown, with the factory edge on the line.” Using the factory edge ensures a perfectly straight fence without any additional milling.

Additional Saw Enhancements

Consider adding the following enhancements to your circular saw guide for more convenience and precision:

• Adjustable stops: Incorporate adjustable stops on your DIY guide for repeated cutting of the same length. This saves time and adds uniformity across multiple pieces.
• Angle cuts: Modify your guide to assist in making angle cuts. By adjusting the fence and checking that it’s securely clamped, you can achieve precise angled cuts for projects requiring miter joints or beveled edges.
• Splinter guards: Attach a splinter guard along the cutting edge of the guide. This reduces splintering on the cut edge, providing a cleaner finish.

Pro Tip: Norm Abram, master carpenter on This Old House, recommends a simple approach to reducing tear-out on circular saw cuts: “If appearances are important, put the good side down when cutting. If you must cut the board face-up or if both sides will show, score the cut line with a utility knife before cutting.” For an extra measure of protection on finished surfaces, he suggests taping the bottom of the saw shoe with duct tape so it can’t scratch the finish.

Using Your DIY Circular Saw Guide

Once you’ve created your DIY guide, using it is straightforward. Here’s how to make the most of your new tool:

1. Mark your cut line on the workpiece.
2. Align the edge of your guide’s base with the cut line.
3. Clamp the guide securely to your workpiece.
4. Place your circular saw against the fence and make the cut.

This method leads to consistent, accurate cuts without the need for additional measurements or adjustments.

Circular Saw Safety Considerations

Safety should always be a top priority when using a circular saw and guide. Follow these guidelines:

• Always follow the manufacturer’s safety instructions for your specific saw model.
• Keep your hands clear of the cutting path.
• Make sure your workpiece is properly supported and secured.
• Unplug the saw when making adjustments or changing blades.
• Wear appropriate protective equipment, such as safety glasses and hearing protection.

Pro Tip: Tom Silva, This Old House general contractor, warns that when a motor slows down, “the blade heats up and dulls quickly.” This not only produces a poor cut, it’s dangerous because the blade can climb out of the kerf and push the saw back toward the user. Always ensure your saw has enough power for the material you’re cutting.

Set the Right Blade Depth: As Norm Abram advises in This Old House Magazine, proper blade depth is crucial for safety. Set the blade so that its bottommost tooth extends no more than about ¼ inch below the workpiece. This minimizes the risk of kickback and leaves fewer exposed teeth beneath the cut—a simple adjustment that makes every cut safer.

Tips for Maintaining Saw Guide Accuracy

To maintain the accuracy of your cuts and the longevity of your guide, implement these tips:

• Keep the base clean and free from sawdust buildup.
• Re-calibrate the guide if you notice any deviation in cuts.
• Regularly check the fence for straightness and reattach if necessary.
• Replace the guide if it becomes damaged or worn.
• Store the guide flat to prevent warping.

Pro Tip: Tom Silva, This Old House general contractor, emphasizes the importance of proper tool storage and daily maintenance. At the end of each work day, Tom blows debris off power tools with compressed air while wearing safety goggles. For cords, he advises: “If you pull the cord tight and wrap it around the body, the cord’s wires will eventually break, just like a shirt hanger that’s been bent too many times.” Instead, tie each cord into a figure eight and let it hang loose — the same care applies to your circular saw and its guide.