The circular saw is a DIY woodworking and power tool that is used to cut wood by the cutting action of a toothed disc that spins at high speed. And although there are other circular saws, or special cutting discs that we can install in our woodworking machine, which serve to cut other materials, in this blog, as you already know, I focus mainly on carpentry work. So I'm going to focus on circular wood saws.
✔️ What is the circular hand saw ?:
The circular saw is a tool that uses a serrated disc to cut wood. For this reason they are also often called disc saws. And although some people sometimes refer to table saws as disk saws, when I talk about a disk saw or circular saw, I always refer to the portable handheld power tool that I am talking about in this post.
As for the cuts in wood that we can make with this carpentry and DIY tool, these can be: straight cuts in the direction of the grain (to the thread); cross sections at 90 degrees with the grain, or at an angle, or miter with respect to the wood grain; or cuts with the cutting disc tilted. And it is that with the circular saw we can only make straight cuts (well, except for some special techniques in which we will not enter), but with the advantage that we can cut faster and even get cleaner and more precise rates than with other machines like jigsaw.
⚙️ Parts of the circular saw:
We will see below the various parts of a circular saw, and the various systems they have to adjust them to the cuts we have to make in each of our carpentry projects.
Parts on the motor side of the circular saw:
On the motor side of the disc saw we have the plastic casing that protects the electrical parts, prevents us from touching the electrical parts, and has the necessary elements to operate this electric saw when cutting wood or other materials.
1.- Ignition trigger:
The trigger is the button we press to turn on the disc saw. It is generally found at the bottom of the handle.
2.- Handle and knob:
The handle is used to hold the circular saw with one hand while pressing the trigger. And after the handle we usually have the knob, which is used to hold this power tool with the other hand as well. And it is that while we cut we must always hold the saw with both hands, firmly and always attentive to any unforeseen as possible kickback or kickback.
3.- Unlock button:
The unlock button is used to unlock the trigger and to be able to actuate it. This way we avoid accidentally turning on the saw blade. Contrary to the jigsaw, this button does not serve to keep the trigger pulled
4.- Circular saw motor:
The motor of the circular saw can be connected directly to the cutting disc or by means of an endless screw. The nameplate gives us the power in watts and the revolutions of the turn. As for turning revolutions, it is important to take them into account when installing a new cutting disc, since cutting discs usually have a limitation in terms of the maximum revolutions at which they can rotate.
5.- Access to change motor brushes:
Over time the brushes that carry the electric current to the saw motor become worn, so it may be necessary to change them. In order not to have to open the entire housing that covers the motor, currently saws usually come with easy-to-open plugs that serve as access to easily change the brushes.
Parts of the Saw Cutting Disc Side:
On the side of the cutting disc of the circular saw we have the parts that directly intervene in the cut and some protection systems.
6.- Saw cutting disc:
The cutting disc of the circular saw has a hole in the center to be installed in the machine with the help of a screw, and has teeth on the outer edge to cut the wood. As for the central hole, it must have a diameter equal to the raised edge around which it should settle in our saw. Although sometimes when buying a cutting disc for a circular saw we will also find adapter rings for different diameters. As for the teeth, these can be made of different materials that are harder than the metal of the disc itself. And we will find cutting discs with different number of teeth. Furthermore, teeth can have different shapes, even on the same disc. Thus, the shape and number of the teeth will influence the cutting speed and the cleanliness of the cut.
7.- Divider blade:
In some circular saws we see behind the cutting disc a metal sheet that surrounds a small portion of the disc, remaining a few millimeters from it and following its curved shape but without reaching the full depth of cut of the disc. Thus, it maintains its position with respect to the disc even if we change the depth of cut. This divider blade must have the same thickness as the disc and serves to prevent the cut we make in the wood from closing against the disc, thus reducing the possibility of kickback or kickback.
8.- Toolholder screw:
It is the screw that keeps the cutting disc of the circular saw fixed in position. It can be Allen type or hexagonal head. In case it is Allen type, the circular saw usually comes with the necessary wrench to loosen and tighten the screw. And to prevent the cutting disc from moving while loosening and tightening the screw, it is necessary to block the disc either with a piece of wood or by using the cutting disc lock button provided by some of these power tools.
9.- Cutting disc lock button:
When we want to change the cutting disc of the circular saw, it is necessary to lock the cutting disc to tighten or loosen the screw that holds it in place. For this we can use a piece of wood that blocks the disc, or else in some circular saws we will find a button that when kept pressed blocks it. It does not hurt to also know which way to turn the clamping screw, because if even pressing this lock button does not loosen the screw, perhaps we should turn it to the other side. In direct axis saws (see below in types of saws) the screw is usually tightened clockwise (normal for all screws), but in a mini saw that I have an endless screw (see below), the clamping screw is tightened counterclockwise.
10.- Washers to seat the cutting disc:
To install the cutting disc on our circular saw we must put it between two washers that are embedded in the axis of rotation. The end of the axis of rotation we will see that it ends in a more or less rectangular shape, so that the washer that goes over the disc fits in that way. So the clamping screw presses the upper washer when we insert it into the hole in the axis of rotation. As for the other washer, the lower one, it is very important when buying a new disc, since the central hole of the cutting disc must fit perfectly into the circular flange that we have in that washer. Although some discs come with rings that allow the disc to be adjusted to different washer sizes. And even on some circular saws that lower washer has a flange on one side and another with another dimension on the other side.
We can also have a washer for when the hole in the cutting disc is greater than the diameter of the seat in the tool holder. So many times, when buying a new cutting disc we see that it comes with simple washers that serve to adapt it to different models or brands of circular saw.
11.- Mobile Guard:
It is the guard that protects the bottom of the cutting disc, and that protects us from cutting ourselves in the case of turning on this power tool when we are not cutting with it. What is not clear to me is if this guard will close fast enough in case of kickback of the circular saw.
So when we want to cut a piece of wood, when we bring the disc closer to the edge of the wood, the guard will begin to open to allow the disc to contact the wood. This guard includes a tab to open it if necessary if for any reason it does not open by itself. For example in cuts with the disc at 45 degrees the mobile guard usually has difficulties to open, so we must use the tab carefully while we start the cut.
12.- Fixed guard:
The fixed guard is the rigid casing that surrounds the top of the cutting disc. It serves as a protection against cuts and also to guide the sawdust that is produced towards the suction inlet that is in the fixed guard itself.
13.- Suction intake:
The suction inlet is a small tube (or sometimes a simple opening) that protrudes outwards or towards the rear of the fixed housing. It is used to evacuate a large part of the sawdust that is produced when cutting wood. It is also suitable for attaching a vacuum tube, although sometimes connecting a vacuum tube here can make working with the disc saw uncomfortable and even dangerous. I talk about this a bit later in the section on the dangers of circular saw.
14.- Metal base of circular saw:
The metal base is the base that we rest on the wood to be cut (or on a cutting guide in some cases), and slide on it as we proceed to cut the wood.
15.- Cutting depth regulation:
the system for regulating the depth of the cut, on the back of the disc saw or on the side, is usually a wing nut or a lever that we can loosen to be able to lift the cutting disc with respect to the metal base. We only need to loosen or tighten in one place, because at the front there is a hinge that allows the rest of the saw blade to be tilted forward with respect to the metal base.
16.- Disc tilt adjustment:
Similar to the cutting depth regulation system, we have a cutting disc inclination regulation system. But in this case we have two wing nuts that we can loosen to tilt the saw laterally with respect to the metal base.
17.- Disc tilt scale:
When changing the cutting inclination we can be guided by a scale that tells us the degrees that we are tilting the disc, but it is not a very reliable scale and it is recommended to have another system that allows us to verify or adjust the angle. I usually use a technical drawing plastic square, or architect's square, to check the angle of inclination at 45 degrees.
18.- Side guide for parallel cuts:
In the metallic base we also usually have a couple of notches in which to fit a normally metallic lateral guide that we fix in the desired position. This allows us to make parallel cuts, generally rip cuts, although it is not usually a high quality cutting guide.
19.- Cutting line guides:
These guides are indentations in the front of the metal base that are aligned with the cutting disc. These help us to follow the line of cut when we are cutting with the blade at 90 degrees or with the blade at 45 degrees.
A Types of circular saws:
Direct axis saws:
They are saws with a disc connected directly to the motor shaft or by means of a spur gear system. Thus the cutting disc rotates in a plane at 90 degrees with the motor axis. The turning speed of the cutting disc can be the same as that of the electric motor or that determined by the transmission ratio of the spur gears, if any. These are the most widely used circular saws and are the ones that we usually find in hardware stores in a wide variety of brands and models.
They are lighter than worm gear saws and are more manageable.
Endless saw blades:
Worm saws are disc saws in which the motor shaft drives a worm screw that rotates a pinion. And this pinion rotates the axis to which the cutting disc is connected.
In these saws the cutting disc rotates 90 degrees with respect to the axis of the electric motor. Since the motor is in a position parallel to the cutting disc, these circular saw blades are usually longer and narrower. Being narrower and longer they are useful in wood construction since they can fit in narrower holes and also allow reaching a few more centimeters when we stretch the arm while cutting.
A worm gear system is used to transmit the motor power to the disc. The worm gear is a spiral gear aligned with or parallel to the motor shaft, which rotates a flat gear that is connected to the cutting disc: the motor drives a worm screw that rotates a pinion. And this pinion rotates the axis to which the cutting disc is connected.
The worm configuration makes the blade rotate slower than direct-axis saws (the cutting blade rotates slower than the motor), but in return these circular saws have more torque. By cons they are somewhat more difficult to handle.
I do not have a "normal" worm saw, but I do have one of those mini saws that have been catching on lately (I can't quite see their grace). And these mini saws work with one worm gear. The truth is that the one I have I only used once, and despite how small it was, it seemed very uncomfortable to handle. Also, as it is a cheap circular saw, it has a pretty bad cutting disc that chops the wood a lot. But hey, from the image you will surely get an idea of how the system works with an endless screw.
Wired Electric Circular Saws:
The circular saw of all life, with its power cable. They are the ones I use in my small home carpentry workshop, since it is very rare that I have to use the circular saw outside the workshop or in areas where I cannot connect it to an electrical outlet. They have the advantage that the battery does not run out, and also by being used to unplugging it after working with it, or there is so much danger of accidentally turning it on if I do not go to work with it.
Cordless circular saws:
Good battery powered circular saws are appearing lately, these batteries having a very acceptable duration. Also, we can always have several batteries for our saw, and even some brands allow the use of the same battery in different tools from the same brand.
How is the circular saw used ?:
Security aside, which we will see later, we will see how to use the electric circular saw:
How to cut with a circular saw:
To cut wooden slats or boards with the circular saw, it is advisable to hold one side of the wood to be cut with sergeants (we generally hold the part of the wood that we put on the motor side of the saw with sergeants).
First we mark the line of cut, and we adjust the depth of cut of the circular saw so that no more than one tooth protrudes from the bottom of the wood to be cut. This way we will get a cleaner cut and we will also reduce the effect of kickback. And we proceed to cut with the saw, holding the circular saw with both hands whenever possible.
One trick for clean cuts is to make sure that the good side of the wood to be cut is facing down. And because the circular saw cuts, it makes a cleaner cut on the underside of the wood, while causing more chipping on the top face.
Another trick for clean cuts is to put painter's tape on the wood and paint the cut line on it, since the painter's tape will help to contain the chips that occur when the disc, in its cutting action, pushes the wood towards up. But don't expect this to get a perfectly clean cut either.
My best trick for clean cuts in wood is to use, they are the circular saw, a good quality cutting disc.
Now we rest the front of the metal base on the wood to be cut, turn on the saw before the disc touches the wood, bring the disc closer to the wood and start cutting. We slide the metal base over the wood, making a straight cut until the cut is complete. Thus, in miter cuts (eg 45) or 90 degrees in narrow woods, it may be sufficient to cut by hand, but in wide wood and boards it is necessary to use joinery guides that allow a straight cut. These will also help cut more accurately.
Now, if we are going to cut a board with the circular saw, it is necessary to use a guide to make a straight cut. And we also need a large surface to rest the board on. We are going to see two ways to do this:
a.- I usually cut them on top of my workshop table. I adjust my home guide to cut straight with the circular saw, adjust the depth of cut so that only one tooth protrudes from the disc below the board, and holding the saw firmly with both hands, I cut the board. The problem is that this way I have the cutting disc towards me and the motor towards the inside of the board, and although I already have experience doing this, if you are a beginner in these tasks it may not be the safest way to cut a board. If the chunk of board left on the motor side of the saw is small then I don't have this problem as I can cut on one edge of the table while staying on the motor side.
b.- Another option is to cut the board on the ground. Not directly on the floor, but on top, for example, of a rigid foam insulation board and with the height adjustment of the disc as in the previous case. We adjust the guide and we can cut the board. The advantage is that now we can climb on top of our dash so that we are on the engine side.
We must not forget that we must always bear in mind the dangers of these woodworking tools and never trust ourselves, since the disk saw is one of the most dangerous woodworking machines with which we are going to work and we must always keep in mind that it can a kickback or kickback occurs.
How to adjust the circular saw:
How to adjust the spacer wedge:
As I find on the Internet:
The bottom of the cutting disc should be about 5mm lower than the bottom of the spacer wedge.
The gap between the teeth of the cutting disc and the edge of the spacer blade should be about 5mm.
But I will try to find more information about it.
Advantages and disadvantages of the circular saw:
? Advantages of the circular saw:
The main advantage of the circular saw would say that it is the speed with which it cuts the wood, but it is also that, with good carpentry guides and a good quality cutting disc suitable for the type of work we want to do, we can make cuts perfectly straight, and cut the wood very precisely and very cleanly.
This carpentry tool will help us to pre-dimension the wood, give it the final dimensions, and even make precise cuts when cutting, for example, some recesses to make some joinery joins.
? Disadvantages of the circular saw:
The main disadvantage of the disc saw is that it is more dangerous than other power saws such as the jigsaw or the saber saw.
Another disadvantage is that the disc saw only serves to make straight cuts, so it is not as versatile as a Jig Saw.
Good quality cutting discs for chainsaw are expensive, and we are going to find many cheap cutting discs on the market that give the impression of good quality but make mediocre cuts in wood. Keep in mind that a good brand tool always comes with a cutting disc from that brand. It will not be the best disc of the brand in question, and it will not be a disc with a multitude of teeth for super clean cuts of the brand itself, but it will still be a quality cutting disc that will make better cuts than cheap discs.
⚠️ Circular Saw Hazards:
I guess we have already read the manual of this power tool and its recommendations, right :)? And it is that whatever I say on this page or anywhere else, it should not be accepted as valid if it goes against what the manual of the saw in question says, or what its manufacturer says in that manual or in any other site. With that said, let's take a look at some of the dangers I have encountered myself when using this DIY and woodworking electric machine. Although there are many things that I leave in the inkwell of the computer and that you can find elsewhere, here I will focus more on my / s experience / s.
The main danger of the circular saw is the kickback. Although we will greatly avoid it if we cut dry, straight and flat wood, if we keep the cutting disc clean, if we adjust the cutting height according to the thickness of the wood, if the saw has a separating blade behind the disc, if we hold the saw safely with both hands carrying the cut straight with the help of a guide and we are attentive to any unusual movement of the saw.
Keep in mind that a rip cut (parallel to the wood grain) is more likely to cause a kickback.
Don't you think use a circular saw for gardening or felling, or cut boards that are green or have resinous knots.
We must also keep in mind where the cable is before bringing the saw to the position where we are going to start cutting.
For some tasks it may be a good idea to connect the workshop vacuum cleaner to the area of the housing that covers the cutting disc where the chips come out, but for some cuts the workshop vacuum tube can make it difficult for us to handle the saw, being better to put on a mask. And glasses, better with glasses, although this carpentry tool does not eject the shavings as dangerously as the milling machine.
Also, circular saws are noisy, so better wear hearing protection.
What circular saw to buy ?:
As you may have already noticed if you follow this carpentry and DIY website, and my YouTube channel, I have been buying several circular saws over the years. I have been able to work with several brands and the best recommendation I have is to buy a model that has spacer blade behind the cutting blade. Although it does not prevent kickback 100%, it does help to avoid it to some extent. And also in this case I would bet, if we can afford it, for a good brand saw.
If we are going to look for a cheap circular saw we have to think that surely we will not be able to give it a more or less intensive use, but that it will be for sporadic uses. And remember that a cheap saw brings a cheap blade disc, which will surely make a bad cut. My experience is that good quality cutting tools (discs, cutting blades, blades…) make the difference when it comes to making a clean and good quality cut.
That said, I remind you that a good quality saw always brings a good quality disc. It will not be the best in the range, but it is useful for many of the cuts we are going to make.
And a cheap saw surely will not have gone through good quality control, making it easier for us to get defective.
We should also ask ourselves what we are going to cut with our circular saw. And it is that many times a minisierra is enough. But the worm-type mini saws do not seem comfortable to operate. I would rather opt for a mini-saw that is a small version of the typical direct axis with the disc rotating directly with the axis of the electric motor.
With battery or cable ?. My first opinion is that with cable, since normally (in my case 95% of the time) we are going to use the disc saw in the workshop, and it is very angry to run out of battery or that something breaks in the battery or the connections of these and having to leave a project halfway. If we opt for a cordless disc saw, we must again think that we need a good quality battery.
Yes, I know I am putting a lot of focus on buying a brand name and good quality disc saw, but nowadays we can buy affordable models for around € 100. And a disk saw is a tool that we are going to use for many years.