Micro-adjustable boring head

A boring head having a diametrical bore adjacent a working end thereof, a cutter holder insertable into one end of said diametrical bore, means for mounting said cutter holder within said diametrical bore for limited axial movement while preventing relative turning movement of said cutter holder in said diametrical bore, a first drive shaft rotatably mounted in the other end of said diametrical bore, said cutter holder having an internally threaded longitudinal opening therein, and said first drive shaft having a threaded end portion in threaded engagement with said internally threaded opening in said cutter holder, whereby rotation of said first drive shaft causes axial movement of said cutter holder in said diametrical bore for radially adjusting the position of said cutter holder relative to the axis of said boring head, a second drive shaft rotatably mounted in said boring head, gear means between said first and second drive shafts whereby rotation of said second drive shaft causes rotation of said first drive shaft, said first and second drive shafts having wrench engaging sockets in the outer ends thereof to permit turning of said first and second drive shafts, a first micrometer dial on the outer end of said first drive shaft to provide for rough orientation of said cutter holder during turning of said first drive shaft by engagement of a wrench in said first drive shaft wrench engaging socket, and a second micrometer dial on the outer end of said second drive shaft for precisely measuring the radial adjustments of said cutter holder during turning of said second drive shaft by engagement of a wrench in said second drive shaft wrench engaging socket.