Industry Watch

A circular saw blade is a thin steel disc that flexes under cutting load. When it flexes far enough to rub the kerf walls, friction generates heat that expands the blade into tighter contact. The feedback loop ends in binding.

The blade guard closes in about a tenth of a second. Kickback moves the saw several inches in a tenth of a second. That timing mismatch defines the limits of a safety device racing an emergency that gets a head start.

Gravity pulls unsupported wood downward during cutting, closing the kerf behind the blade. The pinching develops progressively - barely detectable for the first 80% of the cut, then accelerating through the final inches where kickback strikes.