I'm in the process of building a hardwood deck and need to buy a circular saw to cut the tops off of posts that I've concreted into the ground. Circular saws are versatile tools that can be used for cross cutting or ripping timber. Some can be mounted upside down in a table to provide a versatile saw table.
Above you can see an image of a typical circular saw. The blade is in the same plane as the handle and there is usually a trigger on the main handle to actuall switch on the circular saw. Sometimes there is also and additional handle forward of the main handle to allow for simple two handed operation. You can also see on this saw that the motor drive the blade directly and is projected out at right angles to the blade. Some circular saws use a different configuration driving the motor through worm drive.
When choosing a circular saw you should consider the following important factors:
There are four typical standard sizes for circular saws:
I'd suggest buying the biggest diameter circular saw you can but still be able to manage the weight. It is easier to achieve a straight cut using a larger diameter blade.
Basically the suggestion here is to buy the best quality you can afford. Tradesman quality circular saws are ideal.
I'd go for the newer thin-kerf (kerf is the width of the saw blade) carbide blades. They're pretty good all around blades that cut quickly and stay sharp a long time.
There is no point buying a 9¼" monster that weighs 25 pounds if you can't handle it. Circular saws are dangerous pieces of equipment and you should be able to control the unit at all times.
Your circular saw MUST come with depth adjustment. Proper depth adjustment will minimize kick-back. Kick back is where the blade of the saw binds in the timeber cut and the saw kicks back towards you. This is a dangerous situation and should be avoided at all costs. Proper depth adjustment will allow you to set the dept of the blade to 1/8" (3mm) beyond the bottom of the material
Bevel adjustment allows you to cut mitres and so on with your circular saw.
Well I did end up purchasing a circular saw. I ended up with a Makita, the same one as pictured above. I also had the opportunity to use several saws before purchasing this one. An what a difference there is. I used two cheaper units from generic chinese manufacturers. These units did cut, but the standard blade was terrible, the tool vibrated excessively, and the noise was horrendous.