the end of the last century, a Shaker woman was watching two men
sawing a log with a pit saw when a wagon passed by. It was at that
moment that a thought occurred to her to put saw teeth on a wheel
and use the power of the water wheel to saw trees into boards. The
power saw was born! Initially, most of the circular saw blades had
teeth resembling those of a pit saw formed into a circular plate
of steel. Then, with the advent of the Industrial Revolution, numerous
different blade configurations began to appear from many different
manufacturers, but they all had one thing in common...they needed
to be sharpened frequently.
Then, carbide appeared on the scene...a revolutionary new material
that was expensive, but lasted ten times longer than steel. Today,
dozens of different-looking blades can be found on the shelves of
hardware stores and home centers. It's no wonder woodworking tradesmen
and hobbyists alike are often dumbfounded and confused. "Which blade
should I use for what job? How do I make the right choice ?" Let's
talk about that.
To begin with, it's important to remember that the blade and the
table saw work hand-in-hand. A high quality $50 to $100 saw blade
will do little to make your "cheapie" $200 table saw perform more
admirably. However, put that same high quality blade on your Shopsmith
MARK V and the story will be different.
For the sake of clarity, there are two primary terms that will
help you understand why saw blades are so varied. Those terms are
kerf and set. Since the sole purpose of a blade is
to make a cut, it must remove the wood in its path to do so. The
kerf is the path cut by the blade as it moves through
the wood. If this kerf left by the blade isn't slightly wider than
the blade body, binding will result, and that spells trouble in
the form of dangerous kick-backs. There must be clearance here...and
that clearance is determined by the set of the blade's teeth...the
direction or angle the teeth are positioned in order to clear the
wood out of their path as they make the cut.
. . .