Abstract: A boring bar having a body with standard shank portion at one end and a fluted, adjustable portion at the other end thereof which rigidly supports two standard triangular carbide tips. The tips are adjustable simultaneously to the desired size by means of an accurately shaped and angled adjusting plug together with accurate angles formed in the fluted end of the bar itself.

Abstract: A cutting tool having one portion including a cutting head and another portion including a stem, the portions being separately produced from the same or different metals, or nonmetals, ceramics and the like, and then connected together in coaxial relation by a slip, press, or shrink fit of a polygonal shank of uniform cross section throughout its length on either one of said portions into a complementary polygonal socket in the other portion. Novel means are provided for adjustment of the portions generally radially of the cutting axis to offset differences in concentricity due to manufacturing errors and to assure firm and precise coaxial relation of the assembled portions.

Abstract: A spade drill characterized in that the slotted blade clamping end of the holder has non-symmetrical oppositely disposed blade clamping faces, each of which extends close to the cutting end and cutting diameter of the blade on the side of the blade opposite to the side containing one cutting edge thus to provide firm support for said one cutting edge and is beveled at its end to provide a wide divergent passage for free passage of chips from the other cutting edge to the longitudinal obtuse angle groove of the holder which intersects such divergent passage at its wide end.