Which Way Should The Teeth Be Facing On A Circular Saw Blade?

Circular saws are an indispensable part of any workshop because of the versatility the bring to a tool kit. With different blade types and sizes, they are guaranteed to cut through almost any type of material with minimal effort.

They are also quite portable and can be carried around to where they are needed, especially given the cordless battery-powered versions.

In each saw, the blade is the major determiner to the material it can be used on, be it wood, stone, plastic, ceramic and more.

Blades are designed with specific applications in mind so that choosing the right blade for every job is of paramount importance.

What Should be The Ideal Direction of Circular Saw Blade Teeth?

In layman’s term, the teeth of a circular blade should face such a direction so that the tips of the blade dig into the wood. That means the blade should cut upwards at the front. This definition applies to woodworking blades because they are the ones that feature prominent teeth.

Circular Saw Blade Rotation Direction Marking
Circular Saw Blades have a marking showing the direction the blade is supposed to rotate

Almost all circular saw blade would have arrow marked which would tell you the direction the blade should rotate. However, even for these types of blades; you will find different configurations available.

There are rip cut blades with few large teeth designed to ‘notch’ into the wood on the forward stroke. Others are cross-cut and combination saw blades, but despite the different teeth configurations; they all face backwards.

Therefore, the blade of a circular saw should be fixed so that its teeth face the direction of spin. Metal cutting blades are toothless, however, they only feature expansion slots for when the blade heats up.

There are also abrasive blades for masonry that don’t have teeth but instead are made up of rough materials like fiber. (A fuller glossary on circular saw blades is available on this Rockler page.)

You can check out the best Circular Saw Blades of 2020 if you are planning to purchase one.

Which Way Should a Circular Saw Blade Spin?

Circular saws rotate by default in a counter-clockwise direction. The teeth of a circular blade are designed to cut on the upstroke in the forward direction.

This pushes the material forward and towards the blade so that it helps maintain control of the saw and the workpiece. 

Let’s take this further and imagine for a moment that the blade was spinning downward and hits a hard bit. This would result in the saw being kicked up as soon as the teeth made contact.

With a still spinning saw in hand, you can imagine the possible outcome in such a situation.

With the upward spin direction the teeth would be biting more firmly into the work-piece and thereby preventing any mishap. This is an important safety consideration and also keeps the area of cut clean and more accessible for faster and easier cutting.

Why Does My Circular Saw Spin Backwards?

If your circular saw is spinning backwards, you are in a very dangerous situation and should not proceed until you have figured out what the problem is. The most common cause of such an issue is an electrical fault.

Below is a step by step guide to help you solve this problem. 

  • Disconnect the saw from the power source and check whether you had fixed in the blade in the right direction in the first place.

There are always arrows marked prominently on the blade disk itself that will guide you. The blade should be fixed in the direction of spin of the motor, which is counter-clockwise at the front.

  • If the blade is properly fixed, find a fan and connect it to the same socket.

Table fans should spin in a clockwise direction. If it starts spinning in the opposite then it could mean that your power source is faulty.

  • In this case, connect the fan someplace else in the house and see if the problem persists. If it does; find an electrician to check the wiring system. If it is local to the socket, you could try switching circuit breakers.
  • If the problem lies in the saw, you should have it checked because internal connections could be faulty.

Are Circular Saw Blades Interchangeable?

Circular saw blades are interchangeable and this is what makes the saws so versatile. Different blades work for different materials.

The number of teeth on the blade also determines the quality of the cut. Fewer teeth lead to faster but very rough cutting. On the other side, more teeth lead to finer cutting.

Therefore, the blades have to be interchangeable to allow for these kinds of situations.

The changing process itself is very simple and although it varies from saw to saw, it is designed to be as fast and painless as possible.

It involves locking the blade in place, retracting the guard by the lever and unscrewing the lug nut and washer. A new blade is inserted, the nut tightened and the guard released.

(A detailed guide is found at ThisOldHouse.com)

When replacing blades, you need to consider the spin direction and make sure that it corresponds to that of the motor. You also need to think of the blade size.

It is recommended to use the same blade diameter as the one that was previously fixed. It definitely should not be larger than the maximum allowed size.

But most saws will allow you to fix the smaller blades. (To read more about blades and their applications visit this article by us on best circular saw blades.)

Conclusion

Circular Saws are incredibly useful tools that are very handy and easy to use. They are versatile and are equipped with a range of appropriate blades.

These blades can be used to cut much of the material that needs cutting around the home. They can be changed easily so that you can switch between tasks fluidly.

However, as with the other power tools, safety is the number one consideration. Despite the inbuilt features you must take relevant steps to perform cutting tasks safely.

The saw blade should always be fixed such that the motor direction and the direction of rotation marked on the blade are in line with each other. The teeth are designed to cut upwards into the material from below for safety purposes.

It is equally important to not spin them in any other direction. Because it is a danger not only to you but to other people nearby too.

If the saw starts spinning in reverse direction, starts buckling or kicking or even behaving in any other alarming manner; you will have to check it immediately to fix the issue.

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