The theory is that you can cut thicker material with the tip and thinner material with the base, thus changing the size and spacing of the teeth you're using without changing the blade. I used one of these blades on a nailed and screwed-together Dagwood sandwich of solid oak, plywood, laminated particleboard and sheet metal. While the blade had no trouble cutting through it all, I couldn't tell whether the progressive pitch had anything to do with the blade's effectiveness. You'll notice a variety of tooth-setting patterns if you compare blades. The set of the teeth refers to the way they project to the sides of the body, thus cutting a kerf big enough to reduce binding and, together with the gullet, clear debris.
Some blades have a wavy tooth pattern.
Wavy patterns become necessary, according to Ned Wolf of Magna, once tpi gets above about 18 because the finer teeth associated with higher tpi simply are too small to produce enough of a kerf to prevent binding. Wavy patterns reduce binding by limiting the surface area in friction at any one time but also minimize chatter when cutting sheet metal and other thin materials that are not tightly sandwiched between other more-rigid layers. Used by permission. Read our Privacy Policy .