Guide written by:
Dennis, self-taught DIYer, Bristol
A standard circular saw is the ideal tool if you're hoping to make basic, straight cuts on a regular basis. These saws are operated using both hands with one holding the rear handle with the on-off switch and the other on the front handle to guide the tool. Circular saws are designed to rest on the workpiece and can be used to make cuts of any length. These tools can be used to cut boards of different lengths and widths but the thickness of the wood must not exceed the depth allowed by the blade diameter. The depth of cut can be adjusted and varies according to the diameter of the blade. As such, you need to decide what you need before you buy or use the tool; the maximum depth of cut will be specified in the product description.A standard circular saw features a guard that shields the bottom of the blade and retracts as the cut progresses. These models generally have an rpm of around 3000 to 6000.
A plunge cut saw works in much the same way as a circular saw but does offer an extra feature: when you press down on the rear handle, the blade 'plunges' down to penetrate the wood. The blade itself is shielded by a guard equipped with a return spring.Essentially, this means that you can start cutting a workpiece from any point in the material.
The power rating of a saw essentially determines its abilitytocut through material. Of course, specifications may refer to a no-load speed but this isn't the best indicator of a high-quality tool. Your choice of power rating will depend on your needs and the type and size of workpieces you plan to cut. However, bear in mind that any tool rated above 1800 W will offer serious cutting power. On the other end of the scale, you won't get through an 80 mm x 1.5 m oak timber with anything less than 1200 W!Power rating is also related to depth of cut which depends on the diameter of the blade. A heavy-duty circular saw with a depth of cut of 132 mm requires a 2300 W motor (at least) and will weigh around 18 kg. As you may have guessed, the weight of a saw will increase in proportion to its power rating. To give you a rough idea of weight, a medium-sized circular saw with a depth of cut of 60 mm will weigh around 5 kg.
Cordless circular saws rely on a battery for power. They are less powerful than corded models and are somewhat limited in terms of duration of use and depth of cut. If you go for a cordless saw, it's important to choose a model supplied with two batteries to ensure you have a backup if your tool cuts out before your job is complete. A battery-powered circular saw will provide a maximum depth of cut of around 55 mm.
Cordless circular saws generally feature a Lithium-ion (Li-ion) battery. Voltage refers to the 'power' of the battery and this ranges from 12 to 24 V (around 18 V on average). Li-ion batteries are lightweight, quick to charge, long-lasting and do not have a memory effect. The ampere-hour (Ah) determines how long the battery can be used before it has to be recharged; this ranges from 3 to 5 Ah. Some Li-ion batteries feature a charge indicator which can be handy as these batteries won't slow down as they run out of power – unlike nickel cadmium (Ni-cd) batteries which will lose efficiency as they discharge.
Controlling your circular saw's action with some kind of guide will immediately improve the accuracy of your cuts. Most circular saws are equipped with an adjustable guide which is fixed parallel to the base. However, this system isn't always helpful – especially when you're cutting a long way from the edge, or if the edge isn't straight. Some saws are equipped with a laser guide but the precision of the cut still mainly comes down to your own concentration!Maximum control is achieved with an aluminium guide rail, complete with non-slip brackets or clamps, which is placed on the workpiece. The base of the saw slides along the rail ensuring a perfectly straight cut.
Considering the fact that the blade of a circular saw can rotate at speeds of up to 6000 rpm, it's a good idea to invest in some extra safety features. Depending on the model, you might find one or several of the following:
Circular saws can also be mounted beneath a workshop table or multipurpose workbench. This set-up allows you to transform your handheld circular saw into a makeshift table saw. You can even add your own guide rails and sleds to make mitre cuts.
When picking a circular saw blade, you'll have to think about size (diameter), material, number of teeth and the size of the bore hole.
Each circular saw is designed for a specific blade, the diameter of which determines the depth of cut:
Depth of cut
The number of teeth dictates the speed of your cut and the quality of the finish. The number generally ranges between 10 and 48. The more teeth, the slower and neater the cut. "Diamond" or carbide-tipped blades are preferable to high speed steel (HSS) blades, which are cheaper but wear out much faster.
Multipurpose blades, as the name suggests, are designed to cut all materials including softwood and hardwood, non-ferrous metals (aluminium, copper, brass), and plastics and laminates.
The bore is the hole that is used to attach the blade to the saw. The size required will differ from one saw to another. Before replacing the blade, remember to check the diameter of the bore which will be indicated on the blade. If you can't find the right size, you can use a reducing ring.
Guide written by:
Dennis, self-taught DIYer, Bristol, 18 guides
I started doing DIY 10 years or so ago, when I bought a house that needed to be renovated. After having installed loft isolation, and having refurbished the bathroom, the toilets, the kitchen, the bedrooms… I built an extension, installed a new fence with a gate and kitted out the house with a solar panel to make hot water. I have poured tens of tonnes of concrete into slabs or into the foundations and renovated the roof… I can say that building materials and tools are no stranger to me! If I had a pound for every hour spent looking up information in forums and DIY magazines to find solutions to my problems, I'd be a millionaire! So passing on my knowledge on tools and home equipment is natural, as it is just giving back what I borrowed.