Circular Saw Basics

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A circular saw is one of the most useful hand held power tools to own and I think every shop should have one. Plus it’s a great tool for making woodworking projects if you don’t have a tablesaw or have a limited space. Since it’s a portable tool, you can build projects anywhere…in your driveway or patio, or even balcony. Here are some circular saw basics to get you started.

Cutting plywood freehand.
Cutting plywood freehand.

A circular saw is similar to a tablesaw, but instead of feeding lumber through the saw, you pass the saw through a stationary board. Unlike a tablesaw though, it is safe to make freehand cuts with a circular saw, although you will get straighter cuts if you use a fence or guide.

What I recommend for Weekend Woodworkers

My Ridgid 15 amp saw is a great deal at only $99. It has a sturdy magnesium base and cuts accurately. Setting the bevel is simple. If that seems a bit expensive, my Ryobi 14 amp saw comes in at half the price. It cuts well, but feels flimsier. If I need to make a lot of accurate cuts, the Ridgid will do a better job, but for occasional DIY stuff around the house, or if you just need a saw from roughly breaking down sheets of plywood, the Ryobi is a good choice.

Parts of a Circular Saw

A circular saw has two handles to help you control the saw with both hands. The rear handle has the trigger that you’ll hold throughout the cut. Some saws have a safety button that you need to press first, to prevent accidental starts.

Two handles on a circular saw
Two handles on a circular saw help you control it’s movement.

Typically, the blade is to the right of the motor, but if you are a leftie, you can also buy left handed saws that will help keep the blade to the side of your body. But some right handers actually prefer having the blade on the left where it’s easier to see.

A left-sided blade arrangement.
A left-sided blade arrangement.

The baseplate of the saw rests flat against the surface of the wood and keeps the blade running at a consistent angle to the wood, usually 90 degrees.

Some saws have aluminum baseplates which are lighter weight and less expensive, but if you plan to use the saw more than just occasionally, you will get better results with a steel or magnesium base. 

This Ridgid saw has a magnesium allow base plate.
This Ridgid saw has a magnesium alloy base plate.

The base tilts for making bevel cuts. This saw has a gauge to set the angle you want and positive stops at 45 degrees and 90 degrees.

Tilting the baseplate for beveled cuts.
Tilting the baseplate for beveled cuts.

You can adjust the saw up and down to make deeper or shallower cuts.

Adjusting the depth of cut.
Adjusting the depth of cut.

All saws have a blade guard. It retracts automatically when you start cutting. Sometimes you might need to manually retract it using this lever. You might use this for making plunge cuts. Sometimes I have to retract it just a bit to get it started when cutting really thin material or beveled cuts. But for the most part, just let it do its job!

Retracting the blade guard.
Retracting the blade guard.

Sizes

Circular saws come in a variety of sizes for various purposes. The most common size is a 7 ¼” saw, meaning it uses 7 ¼” blades. And this is the size I recommend for woodworking and other DIY projects around the house.

You can get battery operated saws or corded ones. I have never used the rechargable kind, but I have heard they work really well. If you don’t have a lot of lumber to cut, it’s probably a lot easier than messing with an extension cord, but corded saws are less expensive.

Blades

A new circular saw will most likely come equipped with a combination or all-purpose blade. This one has 24 teeth and I use it for almost everything. Usually it’s all you will need. If you are experiencing splintering or rough edges when crosscutting or cutting plywood, a finer tooth crosscut or plywood blade up to 140 teeth may give you better results.

Blades with lots of teeth will help you get cleaner cuts in plywood
Blades with lots of teeth will help you get cleaner cuts in plywood

Every saw will have its own unique system for changing blades, but they are all similar. Just check with your owner’s manual. Of course, unplug the saw first. This Ridgid saw has a hex key that stores in the handle so you don’t have to hunt down a wrench when you want to change the blade, although you can use a wrench if you want. The saw will have some sort of button or lever to lock the spindle in place. Press it down and hold it in place while you loosen the nut or bolt.

One important note: some saws have reverse threads! (It’s really frustrating trying to loosen a nut only to realize you were tightening it the whole time!) Remove the bolt and the flange or washer and drop the blade into place, making sure you have it facing the right way. There will be arrows reminding you of the direction of the spin…the blade spins counterclockwise and cuts on the upstroke. Another reminder is that it’s usually safe to assume the blade manufacturers will want their logo to show, facing out.

To change a blade of a circular saw, remove the nut and flange or washer.
To change a blade of a circular saw, remove the nut and flange or washer.
Look for arrows on a new blade to remind you of the direction the saw will spin.
Look for arrows on a new blade to remind you of the direction the saw will spin.

Secure the wood

To get good cuts and to prevent injury, it’s important that the wood you are cutting is held securely in place. A sawhorse or a pair of sawhorses is handy for this, especially when cutting boards or small pieces of plywood. Just clamp the workpiece in place. It’s best to not clamp down the offcut piece because the two halves might collapse in on eachother when you get to the end. This can cause the saw to bind and even kick back. While a kickback on a circular saw isn’t a dangerous as kickback on a tablesaw, it can be very jarring and can cause the saw to lunge toward your body. If your saw does bind or kick back, release the trigger and adjust the wood so it’s not pinching.

It's best to only clamp one side of the workpiece. If both halves are clamped, the wood can bind.
It’s best to only clamp one side of the workpiece. If both halves are clamped, the wood can bind.

But the problem with not supporting the offcut piece is that it’s weight can cause the wood to break and splinter as you get toward the end. And trying to support the offcut with your other hand is awkward and not the best solution.

Clamping one side down is better,m but the offcut piece can get damaged without any support.
Clamping one side down is better, but the offcut piece can get damaged without any support.

Instead, I prefer to cut most pieces on the ground, on top of a piece of styrofoam insulation. This method provides offcut support giving you a cleaner cut and eliminates kickback. For larger pieces, you don’t usually need to clamp the wood down.

Styrofoam building insulation makes a great cutting surface.
Styrofoam building insulation makes a great cutting surface.

Making Cuts

Like a table saw, a circular saw can only make straight cuts. I recommend also owning a jigsaw for making curved cuts. Be sure to check out my jigsaw basics video for lots more.

First, set the depth of your cut by adjusting the blade along the edge of your board. Set it so that it’s just barely deeper than the thickness of the wood and lock it down. There will usually be a scale that indicates the ideal setting for whatever thickness of wood you are cutting.

Set the blade to cut just slightly deeper than the thickness of the board.
Set the blade to cut just slightly deeper than the thickness of the board.

The easiest method for making cuts is to freehand it. In other words, draw a line where you want to cut and follow along. This is handy for rough construction projects and framing where the cuts aren’t critical. Sometimes I use freehand cuts breakdown plywood into smaller, more manageable sized pieces that I can square and clean up on my tablesaw.

To make a cut, set the front of the baseplate flat against the wood’s surface. The base has two notches that tell you where exactly the blade will cut. One is for regular 90 degree cuts and the other is for bevels.

These notches show you where your blade with cut, either for straight cuts or beveled cuts.
These notches show you where your blade with cut, either for straight cuts or beveled cuts.

Make sure you are wearing eye and hearing protection. And it’s not a bad idea to wear a dust mask.

Squeeze the trigger and start feeding the saw into the wood after the blade is spinning. Position your body to the side, not directly behind the saw. Follow the line using that notch for reference. You can also look at the blade from the side.

With the baseplate flat against the wood, squeeze the trigger and feed the saw into the wood.
With the baseplate flat against the wood, squeeze the trigger and feed the saw into the wood.

To get straighter, more accurate cuts, you will need to set up a guide of some sort for your baseplate to ride along. You can use anything for a straight edge including the factory cut edge of a piece of plywood or even clamp a level to your workpiece. There are a lot of store bought options here as well as homemade jigs. I will cover all of these in an upcoming video.

Using a cutting guide to get straighter cuts.
Using a cutting guide to get straighter cuts.

For narrow ripcuts, you can use a guide like this one that rides along the edge of the plywood.

Using an edge guide to make long cuts.
Using an edge guide to make long cuts.

For getting accurate crosscuts on boards such as 2x4s, the simplest method is to use a speed square like this one. Hook this cleat to the edge of your board and run your saw’s baseplate alongside.

Using a speed square to make accurate crosscuts.
Using a speed square to make accurate crosscuts.

 

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