A circular saw is perhaps the most useful power tool found on any home building site, and being successful as a carpenter requires that one develop their skill in using this powerful, but dangerous tool. For fine woodworkers who work primarily inside a woodshop with woodworking machines such as table saws and band saws, is there a place for the circular saw?
While I can’t speak for every woodworker, I will say that I regularly use my circular saw in the woodshop, because it is quick, portable and I’ve learned how to use it effectively and accurately. For one-off cuts, it’s a lot quicker than setting up a machine to make the cut. For that reason, developing your circular saw cutting skills is a worthy investment.
With that in mind, here are some tips to help you improve your skills. First of all, the base of the saw must always stay flat on the wood being cut. If one side of the base creeps upward, you lose control, or the blade may bind when you do push the base back down onto the wood.
Second, make sure to set the depth properly for your cut. If you’re cutting 3/4-inch plywood, there’s no reason to have 2-inches of the blade sticking out beneath the saw’s base. In the case of plywood, you’ll likely get a rougher finished cut with so much blade exposed.
When making square crosscuts on dimensional lumber, one of the easiest ways to make sure that your cut stays square is to use a combination square (sometimes referred to as a rafter layout square) as a guide for the base of the saw. To use the square, measure the desired distance of the cut using a tape measure, and make a mark at the desired length. Then, align the lip of the square along the far edge of the board, and make a pencil mark square (or perpendicular) to the long edge of the board. Then, slide the square a few inches to the left of the mark and position your saw against the line ready to make the cut. Slide the square back to the right so that the left edge of the saw’s base rests against the square. Then, proceed with the cut, while holding the saw’s base against the square as a guide. With practice, you’ll be able to make precise crosscuts very quickly using a square and a circular saw.
When cutting plywood using a circular saw, you can use a metal straight edge along with a couple of small bar clamps as a guide. In this manner, you are essentially making a makeshift panel saw, but one that can be quite accurate with some practice, and much easier than positioning a sheet of heavy plywood onto a table saw.
To make your marks, I actually find it easiest to measure the width of the base of your saw, from the blade to the outer edge. Then, when measuring to make a cut, subtract this width from the cut distance and make your mark on each end of the plywood. Position your straight edge on these marks, clamp it into place on the plywood and then make the cut with the circular saw’s base flush against the straight edge. Your cut should be the perfect width, and you didn’t have to snap a chalk line on the plywood or draw a pencil line to follow.
One additional tip. In addition to setting the depth of the cut properly, as outlined earlier, I like to place a few pieces of scrap 2×4 under the plywood, particularly one about two inches on each side of the desired cut line. One more 2×4 a bit farther out from the cut on each side will support the board to prevent it from falling once the cut is completed.
Of course, there will be times where you’ll have to make freehand cuts. The question to answer here is, should you align the cut mark on the edge of the base with the cut line, or watch the blade as you make the cut?
Personally, I do a bit of both. I’ll often start out watching the blade as it cuts on the line, but then switch back and forth between the mark on the base and the blade, using both as a point of reference to make sure that I’m cutting where I want to be. Freehand cuts take practice, and in time, you’ll find a method that works for you.