Guide written by:
John, DIYer & IT developer, Brighton
When selecting a circular saw blade, it is important to consider the following:
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.
Clean, fine cuts. Softwood and hardwood, chipboard, non-ferrous metal profiles, plastic, plexiglass sheets. Intensive use.
C1, C2, C3, C4
Carbide 1, Carbide 2, Carbide 3,Carbide 4
Carbide grade scale according to task. C1 and C2 carbides are coarser and more impact-resistant but less durable. C3 and C4 carbides are finer and cope better with abrasive wear but cannot withstand impacts.
TC or TCT
Tungsten carbide tipped
Perfect for high precision in hardwood, softwood, chipboard and composite materials. Regular use.
For cutting double-sided melamine boards, MDF, etc. Intensive use.
Blades uncoated; less durable and less strong. Can be HSS or carbon alloy.
High carbon steel
Used to form most blades.
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.
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.
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.
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.
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!
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.
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.
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.
Guide written by:
John, DIYer & IT developer, Brighton, 71 guides
Since I was a child, I was always interested in manual and technical works. Always fascinated by woodworking, I took advantage of my first flat as a playground. On the cards: electricity (of course, safety first!) and some partition walls; but also decorating with the help of the missus, made-to-measure furniture and little tricks to optimise the space, all the while remaining as original as possible. When the little one arrived, I started building bits and pieces for him! Lacking space, I have not got a permanent workshop and certain tools I dream about but are not part of my collection. Not to worry, I already know a lot about DIY and I have a high-tech profile that I hope will guide you in your decisions!