Hole Saws

A hole saw is a blade which is used for sawing.  It consists of an annular ring.  It makes a hole in the material.  The cut portion is in a circular shape.  The holesaw has saw teeth on the periphery of the ring.  Sometimes, industrial diamonds are mounted on the periphery. 

Holes saws are more efficient than drill bits as all the material need not be removed by drilling.  Once the outer periphery of the material is cut, the material to be removed in pieces. Less power is therefore required. 

The downside is that more torque is required to use the hole saw.  This requires more powerful drills as compared to the drill bit.  Holesaws need to be guided carefully by the operator in the desired direction.  They can easily drift away from the intended direction.