Hole saw

A hole saw comprising:

• an internal saw having a circular sidewall including a working end having teeth and an oppositely located proximal end, a backwall connected to said sidewall and spaced from said working end, said backwall including an aperture concentrically located with respect to said circular sidewall, said aperture for receiving a pilot drill extending beyond said working end of said circular sidewall;
• and
• an external saw having a circular sidewall having a greater diameter than said circular sidewall of said internal saw, said circular sidewall of said external saw including a working end having teeth and an oppositely located proximal end having a plurality of tangs being separated by notches, a base plate having an inner diameter and an outer diameter and having a plurality of arcuate slots located between said inner diameter and said outer diameter of said base plate, said tangs extending into said arcuate slots in said base plate and said circular sidewall of said external saw being affixed to said base plate, said inner diameter of said base plate being spaced from said aperture in said backwall and said outer diameter annular base plate being larger than said diameter of said circular sidewall of said external saw, said base plate including a plurality of apertures located between said inner and said outer diameters of said annular base plate, each aperture of said base plate receiving a fastener for affixing said base plate to said backwall of said internal saw and locating said circular sidewall of said external saw concentric with respect to said circular sidewall of said internal saw.