Making precise cuts with a circular saw doesn't have to be complicated. With a few tools that most professionals already carry, you can quickly make perfect crosscuts when you need them. Here are a few of my favorite methods.
Precise cuts with a circular saw using the Rafter Square
To make precise crosscuts with the miter saw, I rely on guiding my circular saw shoe up the rafters. I use 6" squares for the largest 2×6 lumber and 12" models for wider planks. Plastic rafter squares provide a thick edge of support yet are lightweight enough to fit in a back pocket. Steel and aluminum work well too.
Orienting the point of the triangle of the square towards you is important for two reasons. It provides more guidance where it is needed most at the start of the cut and allows your board hand to wrap around the square and board in a natural position against the thrust of the saw.
In addition to ensuring stability and accuracy throughout the crosscut, this method allows you to skip the step of drawing lines on the board. Simply align the saw's cut line marks with your measurement marks, slide the square onto the saw's base plate. Marking with a ballpoint pen instead of a thick pencil is another great accuracy trick.
Watch our video on this method!
Use a Ruler for Precise Circular Saw Cuts
For longer cuts, especially if you can't see the cut line all the way, cutting against a ruler will allow you to follow a saw-like result with a rattlesnake or worm drive. Measure the exact distance from the edge of the circular saw shoe to the same side of the saw blade.
Once you have that measurement, add it to the original marker and create a new line. Place the ruler over the new mark, clamp it tight, and make your cut.
Editor's note: Check out our recommendations for the best cordless circular saws
Straightedges range from just grabbing a straight piece from the stack as a quick guide to purpose-made guides for flush cuts. The latter reduces tearing and saves you the step of calculating the width of the saw shoe. I like to use a 3/8" plywood strip bent in the middle. With the bow side up, I can hold it securely in place with one hand. With the bow side down, clip the ends, leaving the middle part spring-tight.
Note the depth of cut
Saws with very thin bases or low motor placement may ride on thick squares and rulers. Adjust the depth of the saw for clearance to prevent the blade from moving during the cut. If the motor hits the T-end of the rafter square while the blade is still cutting, just trim some plastic along the top edge of the square to clear it.
If you have any tips for making precise cuts with a circular saw, let us know in the comments at the bottom of this post.