The Circular Saw was invented way back in the early 1920s by a company that later changed it name to Skil. The tool was SO POPULAR that for decades people referred to every circular saw as as "skil saw", which is the same kind of thing that happened with Hoover. The company name became synonymous with what it did. Even today I hear people sometimes calling circular saws "Skil Saws" and if you tell someone you need to do some "hoovering" they know you really mean vacuum cleaning. Funny how that goes ... but I digress. The circular saw is arguably one of the most popular power tools on the planet. The only thing that might bump it would be the power drill.
Sadly, circular saws have created a TONS of injuries over the years and thanks to a number of people who have looked at these injuries and come up with good ways to help prevent them in the future, we now have a pretty good guidelines on circular saw safety. I am happy to report that these guidelines and best practices are being taught to our carpenter and woodworking students in trade schools and colleges and we know what they are learning is working because we can monitor the positive results.
Many, many years ago the first blades I ever used on circular saws were old hardened steel blades and they didn't stay sharp very long. You had lots of choices back then too, you get a blade with 20 or 24 teeth depending on what manufacturer you wanted to purchase from. The good news was that you got pretty good a sharpening your own blades with rusty old file ...
Today we have wide assortment of blades to choose from and lucky for us, most of these are carbide tipped so they last ... like ... 10 times longer than the old steel blades. The downside is that most can't really be sharpened, but at the cost of them now, it all become part of the cost of building.
There are all sorts of different blades from 20 tooth to 60 tooth blades, there are non-ferrous for cutting aluminum and brass and there are ferrous blades for cutting mild steel. There are concrete blades for cutting things like Hardy Plank and cement board and even what are known as fiber blades for cutting metals, similar to what you find in electric grinders.
The very first rule of using a circ saw is make sure you have good eye and hearing protection.
Next ... make sure the saw is UNPLUGGED before you change or replace blades. Some of these saws are too easy to accidentally turn on, oh and don't forget to put the blade in so the teeth or oriented UP into the base-plate.
At this time it's a good idea to get into the habit of periodically checking to make sure the blade guard is working and moving freely to cover the blade. I am astounded how many people have had their legs cut by still rotating blades when the blade guard got stuck and did not cover the still spinning blade.
The next important rule is to set the blade height to a half tooth below the material being cut, this is especially true for wood and other sheet goods. If you are a student in one of the trade schools you may even be working with saws that are permanently set to cut 2" material or less.
The days of installing a blade and cranking the blade all the way down are methods of the past, unless you are cutting through 4"x4" posts.
The final safety rules comes when actually cutting material. It's important that material that could cause the saw blade to bind or kick-back, or where the material will sag near the end of the cut then break off ... that this material be supported throughout the cut, and especially at the end of the cut.
What we don't want is people cutting the wood and at the same time trying to grab the piece that is sagging or being cut off. This invites problems to happen.
The main thing to remember about using a circ saw is to take your time, think about what you are going to be doing and take your time. Rushing through or become complacent about the saw can lead to injury and nobody wants to have to clean blood off of nice clean wood ... so remember to work safely.
Copyright Colin Knecht