Circular saw blade buying guide

When selecting a circular saw blade, it is important to consider the following:

• the materials you plan to cut (e.g. wood, composite materials, non-ferrous metals, plastic, etc.); this will determine the type of blade you need;

• the tooth design: depends on the material you are cutting and the type of cut required;

• the gullet: i.e. the size of the spaces between the teeth; the larger the gap, the faster the cut;

• the bore: i.e. the diameter of the hole at the centre of the blade; this is measured in mm and can be made smaller with reducing bushes;

• the blade thickness in mm;

• the depth of the cut: depends on the diameter of the blade (which varies depending on saw type);

• the blade and teeth tip material; depends on the materials being cut;

• the number of teeth: the more teeth, the cleaner the cut; represented by the letter Z on the blade;

• the number of revolutions per minute (RPM): linked to the diameter of the blade.

Note that expansion slots are incorporated into the saw blade so that the metal can expand as it heats up. Some logos and abbreviations may be specific to the brand or manufacturer.

Saw blade and teeth materials

Circular saw blades are toothed metal discs featuring a hole in the centre called a bore. This hole is used to secure the blade to the saw. Essentially, the bore size must match the size of your saw but you can select a blade with a larger bore provided that you use a reducer ring or bush to attach it to the saw. For obvious safety reasons, the diameter of the bore must also be at least 5 mm smaller than the nut that secures the blade to the bore shaft.

The diameter of the blade must not exceed the maximum size accepted by your circular saw; this information will be set out in the product specifications. Buying a blade that is slightly smaller is not dangerous but it will reduce cutting depth. If you're not sure, refer to the manufacturer's instructions or check the size of the blade currently on your saw.

Teeth are set out all around the circumference of a circular saw blade. This is the part of the blade that is responsible for making cuts. The space between each tooth is called the gullet. Larger gullets allow sawdust to be expelled more quickly. A blade with larger teeth spaced further apart is therefore ideal for rip cuts (i.e. cutting with the grain).

Inversely, smaller teeth allow for a finer finish, particularly when making crosscuts (i.e. working against the grain). Of course smaller teeth will mean slower cuts.

It is important to note that the gullet size can actually be more important than the number of teeth featured. A 130 mm blade with 24 teeth will have the same gullets as a 260 mm blade with 48 teeth. If it's all sounding a bit complicated, don't worry – blades are usually marked to indicate the type of job they are equipped to handle whether this be coarse work, finishing work or a range of tasks.

The number of teeth isn't everything and the shape of the teeth themselves can vary depending on the type of cutting task they are designed to handle.

Alternate top bevel teeth (ATB)

These teeth feature a bevel design that alternates between right-hand and left-hand bevels. A common design suited to a range of applications, ATB teeth are best for crosscuts but can also handle light rip cuts. They will work on most natural woods and are also able to get through tougher composite materials like plywood.

Negative hook angle

These blades are designed for radial arm or mitre saws. The tips of these teeth flank backwards to slow the feed rate. This also reduces the risk of kickback and makes the blade safer to use.

Triple chip grind

This tooth pattern alternates flat top (FT) teeth with a special-'trapeze' shaped tooth. The chamfered teeth cut coarsely through the material while the flat teeth finish off the cut. The combination of these features makes these blades ideal for finishing work.

Nail-resistant teeth

Scrap lumber or demolition lumber may contain hard foreign bodies such as nails or gravel, which can break a conventional saw blade. The teeth of these special blades are narrower and are made of a softer carbide that absorbs the shocks. These blades are perfect for cutting up wooden pallets!

Anti-kickback teeth

A shoulder at the back of the tooth prevents the blade from getting carried away by limiting the amount of material cut by each tooth. Otherwise, there is a risk of kickback which could be dangerous. These teeth are found on blades with larger gullets.

HSS blades 

High Speed Steel (HSS) blades are inexpensive and can be sharpened easily – which is useful, as they tend to dull quickly. These blades are designed to be used with solid wood. While HSS is an increasingly rare option for circular saws, you will often find these blades on log saws.

Carbide-tipped saw blades

Blades with carbide tips can cut up to fifty times longer than bare steel blades. This type of blade is therefore a great option for cutting hardwood, plywood or chipboard which can all dull steel blades very quickly. Note that this type of blade is not as easy to sharpen as other blades. Tungsten carbide is often abbreviated as TC or TCT (tungsten carbide tips).

Materials such as plastic or non-ferrous metals and light alloys cannot to be cut with just any blade.

Blades designed specifically for these materials will generally be made of tempered steel and will feature a lot of tungsten carbide- or carbide-tipped teeth to ensure accurate cuts. These blades have a negative angle of attack to minimise the risk of kickback.

These blades are often referred to as multi-material blades.

1. Check the features of your saw. Once you know the diameter and bore size of your saw, you just have to select a blade to suit your needs.

2. While log saws and mitre saws require special blades, the blade you choose for your circular saw will depend on what you will be using it for. Bear in mind that you will have to weigh up cutting speed and quality of finish.

3. The blade application is often indicated by the manufacturer making it easier to narrow down your choices regarding gullet size and tooth type.

4. Universal, multi-purpose blades offer a good balance between cutting speed and quality of finish if you don't use your circular saw that often.

5. The various logos and abbreviations can be confusing. In order to make the right choice, follow the manufacturer's recommendations. If you only want to study one feature, think about the design and material of the teeth.