holesaw

A hole saw (also styled as holesaw) is a saw that is in the shape of a circle. It is used in a drill to cut large holes in reasonably thin material.

Holesaws have the same general mechanical construction as the diamond core drill bit, but, instead of the abrasive effect of diamonds, the holesaw uses the cutting effect of saw teeth. The open end of the saw's cylinder is milled with saw teeth. Instead of masonry, the holesaw is suitable for cutting wood, plastic, soft plaster or soft metal.

The placement of the saw teeth makes the cut annulus slightly wider than the cylinder wall thickness, so the cylinder doesn't rub in the cut. Just as in the diamond core drill bit, the cylinder is mounted on a mandrel — an arbor with a centre pilot drill — and has sloping slots to clear sawdust.