An improved dual blade boring tool having a solid surround housing portion in which a pair of parallel spaced transverse channel openings extend perpendicular to the longitudinal axis of the rotatable tool, a pair of dual cutter insert members are mounted in the channel openings, respectively, and are moved in opposite directions to each other responsive to rack and pinion movements of a rotatable cylindrical shaped cam member having at least a rack portion and being meshed to engage pinion portions provided on each of the dual insert members, whereby the rotation of the rack portion of the cam member converts to reciprocating movement of each of the meshed insert members to move oppositely disposed insert members in opposite and corresponding linear directions with respect to the surround housing of the boring tool.
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