Any imbalance in a circular saw blade will cause vibration. This imbalance can come from three places, lack of concentricity, uneven brazing of the teeth, or uneven offset of the teeth. Each causes a different type of vibration, all of which increase operator fatigue and increase the severity of tool marks on the cut wood.
Balance
Concentricity refers to how well centered the arbor hole is in the blade. Even a slight deviation, as small as 1/64” (0.015”), can create an enormous amount of vibration. To reduce the chance of this happening, the exterior of the blade plate and the arbor are all cut by Computer Numerically Controlled (CNC) lasers as one operation. With carbide tipped saw blades, the teeth are brazed to the blade plate. Hand brazing would create an imbalance, as a human operator would not get the exact same amount of brazing on each tooth. Automatic or robotic brazing equipment is used to ensure the necessary level of consistency.
It is possible to have both high speed steel and carbide steel teeth that are offset to one side or the other of the blade. A certain amount of this is often designed into the blade. However, it is always offset by the teeth on either side. In other words, one tooth would be offset to the left and the next would be offset to the right by the same amount. By keeping this consistent, the possibility of imbalance is eliminated. The least desirable thing that can happen is saw blade warping and breaking of tooth. The whole symmetry is ruined then. Fixtures, which hold the teeth firmly in place during brazing ensure precise location of the teeth.
Anti-vibration Holes
Even with all these steps, a blade can still encounter vibration, either due to the saw or variations in the material being cut. To diminish vibrations caused by centrifugal force and imbalance in weight, blades are carved with tight slits in the middle of a blade plate, between the arbor and teeth. Many circular saw blade manufacturers deal with this issue by cutting holes, usually at the ends of the expansion slots. These slots usually begin and end with a small hole, having a laser-cut shape like the letter ‘S’. Laser cutting is essential for the dimensional precision. Holes help to dissipate the vibration. In some cases, the anti-vibration holes are filled with softer material, such as brass or copper to help absorb the vibration. Anti-vibration saw blades are designed to prevent undesired effects and perform smooth cuts without stabilizers. They are good against noise too.
Stabilizers
Blade stabilizers can be placed next to the blade to help reduce vibration. These stabilizers are metal plates, which help to stiffen the blade plate. The drawback in using blade stabilizers is that they reduce the blade’s maximum depth of cut. However, in cases depth of cut is not critical, blade stabilizers are a useful option. Saw blade rubber dampeners and scoring blades aren’t required if you simply use a quality blade.