Can anyone actually tell us which circular saw is the best?
I mean seriously, how can anyone tell you what is the right tool for you, if they don't know what you will be using the tool for, or how often, or what you are willing to pay, etc?
So the best that I can do is to tell you that I may not be able to pick the best one for you exactly, but I can definitely tell you about a bunch of factors that will enable you to be able to make that choice on your own. If you don't want to read through the entire article, you can skip down to the bottom for the summary information.
Two Types of Circular Saws
First off, let's start by talking about the two kinds of saws that are on the market. I am not referring to cordless and corded models, but to sidewinder and worm drive versions. The difference between the two is basically the position of the motor. Your typical use of the saw will be a factor in determining which might be the better choice.
On these kinds of models, the motor is situated at the back of the saw. The spinning motor doesn't turn the blade directly, but uses gears to slow down the speed of the blade, but at the same time increasing the power (torque). A typical blade speed is about 4500 rpm. This makes the saw quieter as well.
The stronger torque means that it can more easily cut through larger pieces of wood and lumber than the sidewinder version. The extra gearing however increases the weight of the saw so it's a bit more difficult to handle. My recommendations for carpenters or construction trades is that they are probably better off using a sidewinder.
This circular saw has the motor directly spinning the blade at a faster speed of about 5500 rpm. This is the more common type. The benefits of this kind of saw is that it is lighter, easier to handle, and more portable. Strangely enough, since the motor is on the right side of the blade, it makes it more difficult to follow a cut line than the worm-drive version. For woodworkers, a typical use of this saw might be to reduce a large sheet of 4x8 plywood into a more manageable size before making the final more precise cuts on the table saw.
Corded and Cordless Models
No need to go into too much detail here as we all know what this means. A cordless model will be more portable (and is usually smaller), but a corded model will have more power and unlimited running time comparatively. For that reason, a corded model is the more versatile tool as you can use it to cut other harder materials such as masonry or metals (with a blade change of course).
How this comes into play for a typical wood worker I am not too sure though. Other than that, I would say that if you are frequently on job sites that you will have trouble finding a power outlet and won't have a generator either, then a cordless model will be for you. Otherwise stick to the corded models.
Most circular saws are in the range of $100 to $200 dollars. If this is a tool that you will be working with often, then I would suggest to stick to the higher end. If it's a tool that you need but will typically be using only once in while, then there's no need to get the 'best' circular on the market. In any case, the price range is not that great, compared to different model table saws for example. It doesn't take higher end models out of the typical budget range. Even the cordless models fall mostly within this cost range as well.
The circular saw is nothing without the blade. So, although this doesn't touch on the saw itself, it is one of the most important aspects of a good saw. As always, the more teeth a blade has, the less tear-out the workpiece will be prone to.
With a circular saw we are not as concerned at finding the right blade as we are with the table saw. A circular saw is more of a rough cut tool than a precision tool, so we are more apt to talk about the blade capacity, or depth of cut. The larger diameter the blade, the deeper it can cut.
The most commonly found blade diameter is 7-1/4 inches. To put this into perspective, a saw with a blade capacity of more than 6 inches can slice through a piece of 2 inch lumber using a 45 degree angle in a single pass. Another common size, a 5-3/8-Inch Saw Blade , can cut through 2 inch lumber with one pass at 90 degrees but will need two passes using a 45 degree angle. If you already have a miter saw, then these depth maximums won't be an issue for you.
This again is more important information for construction work than it is for the more refined woodworking tasks. But, if you will be using this saw to rough cut lumber, then you will need to think about how much thick stock you will be cutting. Or will it be used more for cutting flat panels? In which case you can go ahead and look at the smaller models, which will be lighter and easier to handle.
Now that we have covered the main differences between saws, we can start getting into some more details. When searching through circular saw reviews to help with your purchase, here are a few more details that you can take into consideration.
Mentioned before about cutting 45 degree angles, the beveling capability of the saw lets you tilt the base to produce angled cuts. If you think you will be making frequent changes to the angles you are cutting, look for tool-less adjustment and positive bevel preset stops for quick adjustment and accuracy when cutting angles.
Cutting Line Visibility
Oddly enough, if you are right handed which most people are, the line of sight on a circular saw can make it difficult to follow a cut line because of the motor situated on the right. There are two manufacturer answers to this. One is the simple addition of a notch on the blade guard as a kerf indicator. The other is a laser projection to help keep your cut straight on long cuts.
Actually, besides those two enhancements there can be the addition of third item and that would be a dust blower. But unlike a jigsaw, I've never had a problem with sawdust accumulation on top of the work piece obscuring the line. Maybe because most cuts with a circular saw tend to be of shorter duration perhaps.
Electric Brake System
This one comes under a safety enhancement. The number one woodworking tool that causes hospital visits is the circular saw (Monash Univeristy Study, table pg 8 ). An electric brake stops the blade quickly after you have released the trigger. It works by reversing the flow of electricity in the saw motor when the trigger is released and reducing the momentum of the blade. In my opinion, a very important feature to have.
There of course even more features, like dust ports or dust bags, easy change blade systems, rip guides for short cuts, adjustable handles, plus a few other minor things that manufacturers think up every once in a while. But for the most part, these are nice to have extras that are included with the saw that you already chose to buy by deciding on the other major factors.
Alright, so I promised a summary and here it is.
• If you will be using this saw for carpentry/construction purposes and often cutting thick lumber, then look into a worm-drive model. (Unless you have spaghetti forearms because they are heavier, or short on cash because they are more expensive.) Otherwise get a sidewinder, which is the most popular.
• Get a corded model. (Unless you will be using this saw in the backwoods without electricity.)
• Get a smaller bladed version (lighter and easier to control) if you will be cutting flat materials like melamine sheets or plywood, or if you already have a miter saw (that you would use for cutting thicker lumber with angles).
• Of all the extra features, the one most important need to have (for safety) is the electronic brake.
Lastly, after you have narrowed down your choices from the list above and determined what circular saw features are crucial for you to have, get yourself over to a store and handle some models. See how heavy they are, see how they feel in your hand, test out the beveling action, can you read the markings, things like that.
Now, I know I didn't give you a definitive answer, but that's how you will be able to chose the best circular saw (for you).