All About Saw Blades
THE FOUR BASIC TYPES OF SAW BLADES
Flat Ground Blades (A) have teeth that are set to alternate at equal right/left angles. These blades actually shave off the wood fibers, much like the knives of a jointer, thickness planer or hand plane.
Hollow Ground Blades (B) are tapered and get narrower as you move from the teeth on their outer perimeter towards the arbor hole near the center. Often referred to as planer blades (because they make such smooth cuts), the teeth of a hollow ground blade have no set and the necessary clearance is provided by the recessed sides of the blade. These blades should be reserved for finish cuts only and should not be used for heavy, sizing cuts.
Thin Rim Blades (C) offer the same basic characteristics as Hollow Ground Blades...except their concave taper is usually only a couple of inches deep, limiting their depth of cut. Thin Rim Blades are always carbide-tipped and are designed primarily for making finish-quality cuts on laminates and tough woods, while taking a narrower kerf.
Swedge Blades (D) feature teeth that are wider than the body of the blade and slightly squared like small spades. The swedge design is common with the chipper teeth on steel stacked dado blades and provides a relatively smooth kerf as it cuts.
It's important to note that no single blade can perform all cuts perfectly. For example, an all-purpose combination blade is designed for both crosscuts and ripping but isn't the best blade for making either cut.