Patent ID: 8858135

Claim:
A cutting guide useful in positioning and guiding a rotary blade operatively engaged in a chuck of a rotary cutting tool in an alignment proximate a ring retaining groove of a sink drain fitting comprising, in combination: a circular collar conformed for a mating fit within an interior of said fitting including a plurality of radial projections extending from an upper periphery thereof for the support of said collar in partial receipt within said fitting, said collar including a central opening therein; a tubular segment defined by an exterior radial dimension smaller than said central opening in said collar and including an upper peripheral ring on an upper portion of an exterior thereof of a dimension greater than the central opening within said collar and a lower peripheral ring on a lower peripheral portion thereof of a dimension smaller than said central opening in said collar, said upper and lower rings being axially separated from each other by a gap equal or greater than an axial dimension of said collar to accommodate a radial translation of said tubular segment within said central opening limited by the difference between the radial dimensions of said central opening of said collar and said exterior dimension of said tubular segment, said tubular segment including a lateral opening communicating from the exterior into an annular cavity between said upper and lower rings; and said annular cavity formed in said tubular segment conformed to receive in coaxial alignment said cutting tool and said chuck.