The user must ensure that every power-driven circular saw that is used for ripping wood to be provided with a riving knife, which must -
- be placed as close as practicable to the saw blade, but not more than 12 mm behind it, and in a direct line with the saw teeth at the level of the bench table;
- have the edge nearest the saw in the form of an arc of a circle that must have a radius not exceeding the radius of the largest saw blade that can be used on the bench by more than 3 mm;
- extend to a height above the table to within 5 mm of the top of the saw blade; and
- have a smooth surface and be strong, rigid and easily adjustable.