Choose the Right Circular Saw Blade

We've written about table saw blade height, using a miter saw, table saw safety tips, and caring for circular saw blades, but with so many types of circular saw blades to choose from, how exactly do you choose the right one? Work? Even if you know how to use a miter saw like a pro, there are plenty of blades to choose from. Blades with multiple teeth and few teeth, non-toothed blades like continuous rims, wide blades and thin blades, negative and positive rake blades, and then blades that claim to be all-purpose, can be really messy. So we put our heads together and kept it simple to provide you with this helpful guide to help you choose the right circular saw blade.

bite the bullet

The characteristics that determine the functionality of a circular saw blade are:

Number of teeth

Generally, a blade with a higher number of teeth will give a smoother, finer cut, while a blade with fewer teeth will give a rougher cut. The benefit of fewer teeth is faster cutting and less expensive. For most construction jobs, a 24-tooth general-purpose blade will suffice. The blade is very aggressive and helps you rip and cross-cut wood and boards with speed and precision. With the 24-tooth demo blade, you can get the job done quickly, but you won't get a near-finished edge.

Also, keep in mind that our 24-tooth example is for a 7-1/4" blade. When you step up to a 12" miter saw, the 40-tooth blade will be just as aggressive. Not so much the teeth, Rather it is the number and size of teeth per linear inch of the saw blade. Keep this in mind when shopping. A finer thin-cut finishing blade will be better for cutting hardwood and pruning where a cleaner edge is desired.

Generally speaking, the higher the number of teeth (per blade diameter), the smoother the cut. However, this also means that the saw needs to apply more force, and the cut will be slower on average. For a 7-1/4″ circular saw like the Milwaukee M18 FUEL Circular Saw, a 40 tooth or taller blade will give you a cleaner cut, but you don’t necessarily want to use it to crosscut 2×4 lumber for a job website.

Esophageal size

Gullets are spaces between teeth whose size and depth determine how much waste is removed as the blade rotates. You can quickly see that the slot size is a function of the number of teeth.

front angle or rake angle

The hook or rake is where the teeth touch the cutting surface. Positive angles point down the wood surface, aggressively removing waste material, resulting in a faster but rougher cut.

A positive rake angle results in what is known as down-cut or self-feed because it pulls the material in. In applications such as metal cutting, a positive rake angle can be very dangerous.

As you might imagine, negative hooks or rakes cut less aggressively and don't feed themselves, resulting in a smoother surface, but they also don't cut as fast and don't remove as much scrap. You can find metal cutting blades and specialty wood blades that use a negative rake angle.

Angles can also be neutral.

bevel

This important differentiating factor is the angle at which the teeth rotate across or perpendicular to the blade. The larger the bevel, the cleaner and smoother the cut. Some blades have a very high bevel for cutting composite materials such as melamine or other materials with thin veneers that can tear/chip easily when the teeth move away from the material. Bevels can be flat (no angle), alternating, high alternating, or some of the other configurations we'll discuss below.

Slit

This is the width of the tooth at its widest point and therefore the width of the incision. At first, you might guess that the thinner cut was designed for finer woodworking, but it was originally developed for lower powered jobsite or portable saws. We reviewed the ultra-fine, thin kerf 12" miter saw blades and found a lot to like about the various tooth profiles and vibration dampening technology used in these blades.

Thinner kerfs create less resistance while cutting and are therefore better suited to the power needs of these saws. However, the tradeoff is that thinner blades can vibrate or wobble and cause cuts that show blade motion. These blades are especially troublesome when cutting through hardwoods.

New blade technology with a vibration-damping design offers some improvements to the thin-kerf segment (cordless circular saw users, rejoice!).

circular reasoning

Now that we've laid the groundwork, it should be easier to decide which type of blade you want to use for the job at hand. Most importantly, determine which general type of cut you will be making – across the grain or lengthwise. Which cut do you need – rough or smooth?

These questions are easy to answer for natural wood where the fibers run in the same direction. But remember, composites have no fiber direction – so you have neither crosscuts nor tears. It's also important to make sure the blade you choose is designed for the type of saw, power capability, and material you're cutting. Choose the right attachment for the job – Certain types of blades are tool-specific.

tear blade

Choosing the right circular saw blade for slitting can be even more important. These blades have a low number of teeth (usually around 24) and almost no bevel. A fine, smooth finished cut is usually not required to rip a piece of wood. You can save the higher tooth, higher bevel blade for later final dimensions. These blades will remove large amounts of material quickly, but will be rough, and that's okay. That's not to say you can't rip with a general purpose or combination 40 or 50 tooth blade.

Cross cutting blade

Anyone who has used a router on end grain or cut dados on wood fibers will tell you how the drill bit can cause a tear when it leaves the wood (without proper technique or precautions of course!) The round blade tears no difference. Crosscut blades have higher tooth counts (60 to 100) and steeper bevels to prevent tearing.

Specific reasoning?

So while the above guidelines are often true, they are not universal. For any type of rough cut, like framing, you'll find pros using a 24-tooth blade for the speed it offers. The wood will be hidden, so there's no need to create a perfect finish – just careful measurements.

The number of teeth should be increased due to the need for a better finish. Cutting with a very high tooth count reduces cutting speed, but also reduces the amount of finishing work that needs to be done before tearing and mounting the workpiece.

fictional idea

We mentioned that the bevel angle is one of the most important considerations when choosing a round insert after the number of teeth. Now, let's look at the appropriate bevel for the material and type of cut.

flat top

These teeth have no bevel and outperform many other teeth when removing large volumes of material for rough cutting, whether slitting or cross cutting.

Alternate Top Bevel

Teeth slope in alternating and opposite directions (left/right). This will create a clean cut, with the quality of the cut increasing as the angle increases. These blades usually have a mid-range tooth count and are excellent general-purpose blades for ripping and crosscutting. However, keep in mind that hybrid blades are rarely as good as specific cutting blades. Of course, that doesn't mean you can't find this type of blade for most cuts.

Spare top bevel rake or combination

This alternate top bevel blade includes a flat top tooth after a set of multiple bevel teeth. As you can imagine, this bevel works well as a multipurpose blade. Flat-topped teeth have larger gullets to remove large volumes of material. Plus, the bevel helps it cut through material cleanly.

Diablo has started experimenting with pointy points instead of flat teeth for the third grind. Check out our review of how well it works on a framing blade.

High Alternating Top Bevel

As mentioned above, the higher the bevel, the cleaner the cut. As a result, these high-bevel blades produce a very smooth cut with very low tear rates.

Triple Chip Grinding

The blade alternates between flat-topped and double-beveled or chamfered teeth. These specialty inserts are especially suitable for hard and composite materials.

We hope this article on choosing the right circular saw blade clears up the confusion so you can choose the best accessory for the job. If you're a pro and have circular saw blade selection tips, add them in the comments below – or join the conversation on Facebook, Instagram, and Twitter.