Boring tool

Claim 1

A BORING TOOL FOR BORING A HOLE IN A METALLIC ARTICLE COMPRISING, A BODY LONGITUDINALLY INSERTABLE IN AND RELATIVELY MOVABLE LONGITUDINALLY WITH RESPECT TO THE HOLE IN THE ARTICLE AND ROTATABLE ABOUT ITS LONGITUDINAL AXIS, A PLURALITY OF CIRCULAR CUTTER BOTTOMS HAVINMG SUBSTANTIALLY CYLINDRICAL PERIPHERIES AND CUTTING FACES, MEANS FOR SECURING THE CUTTER BOTTOMS TO THE BODY IN SUBSTANTIALLY RADIALLY OUTWARDLY EXTENDING POSITION, WITH THEIR CENTERS ARRANGED IN A PLANE NORMAL TO THE LONGITUDINAL AXIS AND EQUALLY SPACED FROM THE LONGITUDINAL AXIS AND WITH THE CUTTING FACES THEREOF SUBSTANTIALLY PARALLEL TO RADII FROM THE LONGITUDINAL AXIS OF THE BODY BUT ADVANCED AHEAD OF SAID RADII IN THE DIRECTION OF ROTATION OF THE BODY A DISTANCE AT LEAST AS GREAT AS ONE-HALF THE WIDTH OF THE SUBSTANTIALLY CYLINDRICAL PERIPHERIES OF THE CUTTER BOTTONS AND WITH THE CUTTER BUTTONS AXIALLY TILTED OUT OF PARALLEL WITH THE LONGITUDINAL AXIS OF THE BODY TOWARD THE DIRECTION OF THE LONGITUDINAL BORING MOVEMENT OF THE BODY WITH RESPECT TO THE HOLE IN THE ARTICLE, FOR ENGAGING THE CUTTING FACES OF THE CUTTER BUTTONS WITH THE HOLE IN THE ARTICLE AND PROVIDING RELIEF ABOUT THE SUBSTANTIALLY CYLINDRICAL PERIPHERIES OF THE CUTTER BUTTONS BEHIND THE CUTTING FACES THEREOF TO BORE THE HOLE IN THE ARTICLE AS THE BODY IS ROTATED AND LONGITUDINALLY MOVED WITH RESPECT TO THE HOLE IN THE ARTICLE, THE CUTTING FACE OF WACH CIRCULAR CUTTER BUTTON HAVING A CONCAVE SURFACE EXTENDING INWARDLY FROM THE PERIPHERY THEREOF TO FORM AN EFFECTIVE POSITIVE CUTTING ANGLE IN THE CUTTING FACE WITH RESPECT TO THE RADIUS OF THE HOLE IN THE ARTICLE WHERE THE HOLE IS ENGAGED BY THE PERIPHERY OF THE CUTTING FACE.