Fluid pressure operated spotfacing and counterboring tool

A spotfacing and counterboring tool, comprising

• a cylindrical tool holder,
• a generally bell-shaped piston housing surrounding said holder intermediate the ends thereof, and having an annular wall open at one end and closed at its opposite end by an integral, transverse end wall having therein a central opening surrounding said holder,
• a spring retainer surrounding said holder and mounted coaxially in and closing the open end of said annular wall of said housing,
• a piston mounted on said holder in said housing for reciprocation axially thereof between said end wall and said spring retainer,
• said piston having an enlarged-diameter head section confronting at one side thereof upon said end wall of said housing, and having a reduced diameter annular wall section projecting coaxially from the opposite side of said head section thereof toward said spring retainer,
• a spring mounted in said housing between said retainer and said piston and operative normally to urge said piston to a retracted position in which said one side of said head section thereof is seated against said housing end wall,
• said holder projecting at one end thereof coaxially beyond said spring retainer and having a tool bit mounted in a recess therein for pivotal movement between an inoperative position within said recess, and an operative position in which the tool bit projects from the recess,
• means for connecting the opposite end of said holder to a machine tool for rotation thereby, and for supplying fluid under pressure throiugh an axial bore in said holder to said one side of said head section of said piston to shift said piston axially from its retracted position to an advanced position in said housing,
• a tool bit actuating rod mounted in said holder for limited pivotal movement about an axis extending parallel to the axial centerline of said holder and connected at one end to said tool bit to impart pivotal movement thereto, and
• means connecting said rod adjacent its opposite end to said piston and operative when said piston is moved to its retracted position to pivot said rod in a direction to move said tool bit to its inoperative position in said recess, and operative to pivot said rod in the opposite direction to move said tool bit to its operative position when said piston is moved to its advanced position.