Patent ID: 7753626

Claim:
A boring bar, comprising: a shank portion; and a head portion with at least one boring cartridge mounted thereto, said at least one boring cartridge including an axial micro-adjustable differential screw assembly for adjusting an axial position of a cutting insert, and a radial micro-adjustable differential screw assembly for adjusting a radial position of said cutting insert, said axial and radial micro-adjustable differential screw assemblies including a rotatable drive screw with a bore having internal threads with a first thread pitch, and external threads with a second thread pitch different than said first thread pitch, and a non-rotatable adjusting screw having external threads with said first thread pitch being received in said bore of said drive screw, wherein the difference between the first and second thread pitches causes reduced movement of said at least one boring cartridge in relation to movement of said drive screw, thereby providing fine adjustment of the axial and radial positions of said cutting insert.