A circular saw is a great tool and one of the most common tools in the workshop. It was invented in England back in 1780. The circular saw is also known as a buzz saw or commonly called the Skil saw, even though Skil is a manufacturer that makes circular saws. With the right blade, a circular saw is capable of cutting wood, steel, masonry and ceramic tile. Circular saws come in different sizes ranging from 3" to 16". The most common corded size is 7 1/4" and cordless is 5 3/8" & 6 1/2". There are two types of circular saws: IN-Line Saws and Worm Drive Saws.
In-Line Saw - These are the most common types of circular saws and tend to be the least expensive. In addition, they don't weigh as much as the Worm Drive saws. An In-line saw's motor sits perpendicular to the blade and a shaft runs directly from the motor to drive the blade. An In-Line saw will suit most of your applications, and except for changing the blades, they are maintenance free.
3 Circular Saw
Worm Drive Saw - A worm drive is for heavy duty use and tends to cost a little more than the In-Line saws. A worm drive motor is positioned parallel with the blade and uses a gear to increase the torque transferred to the blade. These tend to be a little heavier than the in-line models. Also, worm saws are not maintenance free, you will need to occasionally add a special oil to the motor, which is nothing more than unscrewing a screw and adding the oil, it is very easy.
Circular Saw Features
Electric Brakes - This is one feature I would get, no questions asked. An electric brake stops the motor in about two seconds after releasing the trigger, while a saw without an electric brake will take about 10 to 15 seconds to stop. The electric brake works by reversing the flow of electricity to the saw motor. The reason to go with the electric brake, which most models now offer, is to save limbs and fingers. After you are cutting for a while your arm will tend to get tired, so you want to make sure your safe at all times. Stopping the blade quicker means less chances of getting hurt.
Blade Capacity - As noted above circular saws come in different blade sizes. If you are buying a corded model I would go with a 7 1/4" and for cordless, go with a 6 1/2". The larger blade models are heavier, but in the long run you will have to make less cuts, especially on angle cuts.
Shaft Locks - Make sure your saw has a lock. A Shaft lock is usually a button you press that holds the blade still, making changing the blade easier. If your buying a professional power circular saw, it should have this feature. The cheaper models usually do not have this feature.
Circular Saw Blades
A saw blade is one of the most important parts to a circular saw. Not only having the right blade is important, but also having a sharp blade is important. There are numerous blades for different jobs and below we cover the common uses. If you would like a more in depth explanation on saw blades please follow this link - Blades.
Steel Blades - Inexpensive and good for softwood. Hardwood will make steel blades dull very quickly.
Carbide Blades - Will stay sharp longer than steel blades, but more expensive.
Tile Blades - Usually have diamond tip blades and are designed especially for cutting ceramic tile.
Masonry Blades - These blades are made for cutting concrete, brick, cinder block and other masonry material. They are made of abrasive material.
What to look for when buying a circular saw
I would definitely look for a circular saw that accepts 7 1/4 blades. These are the most common blades; therefore making it easier to buy blades down the road. Also I would look for a saw with a long cord, as you would be surprised how many cords are very short. You can always add an extension cord on, but I would look for a cord that is at least 8 feet in length. Another primary item to look for is an adjustable base plate. This is good for making angle cuts and sometimes comes in very handy.
Cordless Saws - Cordless saws are nice because they have no cords to plug in, trip over or even cut through. However, they lack power. The blades tend to be smaller and therefore they do not cut as quick. Since it takes a lot of power to cut through wood, you will definitely need more than one battery as you will be recharging them often.
Corded Saws - Corded saws are more powerful, but also heavier. If you are going to be cutting a lot of wood, grab the corded model as it will save you aggravation down the road.
I currently own a cordless and corded one. I find myself using both models just about the same. It is just easier to grab the cordless one and start cutting. Most of the carpenters I know or have talked to also own both styles.
Tips on using a Circular Saw
Make sure you have the right blade for the type of material you are cutting.
Blades - Make sure your blade is sharp and not dull. Dull blades tend to heat up more which causes more wear on your tools and more chances to bind.
Set the cutting depth no more than a 1/4 inch thickness of the wood to be cut. This will help reduce the chances of kick backs.
Clamp the wood you will be cutting. This will insure a more accurate cut.
Make sure your wood is clean of nails.
Make sure your saw is up to speed before you start cutting the wood.
Don't force your saw to cut. Let the saw cut by pushing slightly into the wood and letting the saw cut.
Make sure the blade stops before you grab the wood.