Making accurate cuts with a circular saw doesn’t have to be all that complicated. With a few tools most Pros already carry, you can make a perfect crosscut pretty quickly when you need to. Here are a couple of my favorite methods.
Use a Rafter Square for Making Accurate Cuts with a Circular Saw
To make miter saw-accurate crosscuts, I rely on guiding my circular saw shoe against a rafter square. I use a 6-inch square for lumber up to 2×6, and a 12-inch model for wider boards. Plastic rafter squares provide a thick bearing edge and are light enough to stuff in a back pocket. Steel and aluminum work great as well.
Orienting the square with the point of the triangle facing you is important for two reasons. It provides more guidance at the start of the cut where it’s needed most and allows your board-holding hand to wrap around both the square and the board in a natural position to hold against the pushing force of the saw.
Besides ensuring stability and accuracy throughout the crosscut, this method also lets you skip the step of drawing a line across your board. Just line up the saw’s cutline marker with your measured mark, slide the square against the saw’s shoe and go. Making marks with a ballpoint pen instead of a thick pencil is another good accuracy tip.
Using a Straightedge for Accurate Circular Saw Cuts
For longer cuts, especially where you can’t see the cutline all the way across, cutting against a straightedge gives you track saw-like results with your sidewinder or worm drive. Measure the exact distance from the edge of the circular saw’s shoe to the same side of the blade.
Once you have that measurement, add it to your original marks and make a new line. Set the straightedge on the new marks, clamp it down, and make your cut.
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Straightedges range from just grabbing a straight board from the stack for a quick guide to purpose-built flush-cut guides. The latter reduce tear-out and save you the step of accounting for the width of the saw shoe. I like to use a strip of 3/8-inch plywood that is bowed in the middle. Set bow side up, I can hold it securely in place with one hand in the center. Set bow side down, clamping down both ends springs the middle down tight.
Watch the Depth of Cut
Saws with very thin bases or motors that sit low may ride up on thick squares and straightedges. Adjust the saw’s depth for clearance to prevent the blade from shifting during the cut. If the motor hits the T-shaped end of your rafter square while the blade is still in the cut, simply trim off some of the plastic along the top edge of the square so it clears.
If you have any tips for making accurate cuts with a circular saw let us know in the comments at the bottom of this article.