If you are cutting wood, whether ripping or crosscutting, a circular saw is always something that you will have a use for. Circular saws are very versatile tools, and this is mostly thanks to that fast-spinning blade.
For the record, these saws usually have blades that are 7-1/4” in diameter. That said, what if for whatever reason you need a larger or a small blade? Can you use a smaller or larger blade on your circular saw? It’s a bit more complicated than you might think, so let’s take a closer look.
Can You Use a Smaller Blade on Your Circular Saw?
So, your circular saw’s main blade broke, but you still have a smaller one, maybe a 6-1/4” blade. Will this still work in a standard circular saw designed to use a blade that is 7-1/4”? The answer here is that yes, for the most part, you can use a smaller blade on a circular saw. Generally speaking, this is not going to be inherently dangerous. Although, it’s definitely not going to work as well as if you use the right blade.
One thing that you must consider here is the arbor. If you have different blades, particularly from different brands, especially if they don’t match the brand of your saw, then the hole in the center of the blade may not fit over the arbor. That said, if the blade does fit on the arbor, and you are able to tighten it securely, then there should be no problems on this front.
The next thing that you need to consider here is that the cutting depth of the saw is going to be quite limited if you end up using a smaller blade. For instance, if you have an 8” saw, but are only using a 6” blade, then the cutting depth is obviously going to be limited. This is not only because the blade is smaller, but also because the guard is going to come into contact with the workpiece earlier too.
The other thing that you need to consider here is the speed of the saw compared to the speed that the blade in question is rated for. A smaller blade, although it technically won’t spin any faster than a larger blade, does cover less ground with the same amount of RPMs. This means that a smaller blade will take longer to cut the same piece of wood than a larger blade.
However, on that note, a smaller blade, due to the way in which gravity and centrifugal force work, is put under less stress than a larger blade. In other words, a smaller blade has the ability to travel at much faster speeds without the risk of breaking. The smaller the blade, the more speed and centrifugal force it can handle.
Can You Use a Larger Blade on Your Circular Saw?
On the other hand, you might also be wondering if putting a larger blade on a circular saw is fine, or if it is even doable at all. Well, this is unfortunately not the same as with a smaller blade, especially as far as space is concerned.
Simply put, there is only so much space between the arbor or center of the blade and the guard on top of the saw that keeps you safe. Sure, you might be able to fit another half inch or so, but there is only so much space to work with.
That blade might not fit inside of the guard because the diameter is too large. So, whether or not this is a good idea is not the most significant factor to consider. The biggest factor here is whether or not a larger blade will fit in the first place. You just might not be able to mount it.
Now, even if somehow you can fit a larger blade onto your circular saw, it’s still not a good idea. It all comes back down to those RPMs and how much stress a saw blade is under. As covered above, smaller blades can spin faster without the risk of breaking or causing injury.
However, the larger the blade, the slower it needs to move to remain safe. If the blade you want to fit onto the circular saw is rated for a much lower RPM than the saw itself, then the blade may break, snap, or cause injury. Spinning way too fast is a big issue as it puts the blade under too much pressure and stress.
There is also the simple fact that the larger the blade is, the more power is needed to drive it forwards. If the blade is too large, and the motor of the saw is not strong enough, the blade might not be able to spin fast enough. You’re going to have very limited cutting power due to this, and for this reason, a circular saw fitted with a larger blade might not be able to cut at all.
Can You Use a Blade with Different Kerf on Your Circular Saw?
The kerf of a saw blade is simply how wide the blade is. Technically speaking, the kerf refers to how much material is removed width-wise, but it’s effectively the same thing. The answer here is that yes, you can use blades with differing kerfs, especially if we are talking about a smaller blade.
If we are talking about a wider blade, so long as the saw has a strong enough motor to power it, there should not be any problems. Of course, it all depends on whether or not the arbor of the saw is designed to handle blades of differing kerfs.
Summary
As you can see, it may very well be possible to use a smaller blade on your circular saw, particularly if you need maximum RPMs and speed.
As long as the arbor hole is the same size, a smaller blade will do just fine. However, this does not really apply in the other direction. Using a larger blade with a circular saw that is not intended to hold a blade of this size is really never a good idea. It may break the saw or cause injury to the user.
As far as the kerf is concerned, as long as the arbor can hold onto the blade, and as long as the circular saw has enough power to spin a thicker blade, this should be fine.
In case you are wondering how and when to change a circular saw blade, read this article.