A boring bar has a generally cylindrical elongate tool body has a proximal end for mounting to drive unit and a distal end for attachment to a tool head. A passageway extends longitudinally along the central axis of the elongate tool body. A plurality of longitudinally extending cavities are disposed annularly about the tool body. A compressive material is disposed in each of the cavities. An adjustable compression fitting is disposed in at least one end of each of the cavities, where each of the compression fitting can be adjusted to change compression of the material disposed in a respective cavity.

A cutting tool, including a cutting edge portion composed of a cubic boron nitride sintered material, wherein the cutting edge portion has: a flank face; a rake face contiguous to the flank face; and a cutting edge positioned on a ridgeline of the flank face and the rake face, an arithmetical mean height Sa of the flank face is 0.5 μm or more and 3.0 μm or less, the Sa is measured in accordance with ISO25178-2:2012, and an oxygen concentration of the flank face is 10 mass % or more and 50 mass % or less.

The disclosure relates to cubic boron nitride inserts for machining iron-based workpieces, as well as related methods and apparatuses. The insert includes a cutting element containing cubic boron nitride (cBN) in an amount in a range of 50 wt. % to 95 wt. % based on the cutting element, and a binder containing at least one of (i) alumina (Al.sub.2O.sub.3) and a manganese material (e.g., an oxide such as MnO.sub.x) and (ii) zirconia (ZrO.sub.2). The insert can be used for various machining processes, for example turning or boring. Suitable workpieces include iron-based materials or ferrous alloys, for example a cast iron such as compacted graphite iron (CGI).

A core drill bit can include a first region and a second region. The first region can include abrasive particles in a first bond matrix, and the second region can include abrasive particles in a second bond matrix. The first region is connected to the second region. A composition of the first bond matrix can be different from a composition of the second matrix. In a particular embodiment, the first bond matric can include a Co-containing material.

A cermet tool includes from 75-95 volume % of a hard phase and from 5-25 volume % of a binder phase. The hard phase has a first hard phase with a core portion of (Ti, Nb, Mo) (C, N) and a peripheral portion of (Ti, Nb, Mo, W) (C, N) or (Ti, Nb, Mo, W, Zr) (C, N), a second hard phase with both a core portion and a peripheral portion of (Ti, Nb, Mo, W) (C, N) or (Ti, Nb, Mo, W, Zr) (C, N), and a third hard phase of (Ti, Nb, Mo) (C, N). The ratio of Nbs/Nbi is from 0.8 to 1.2, where Nbs is a maximum Nb amount in a surface region and Nbi is an internal Nb amount in an internal region. The ratio of Ws/Wi is from 1.0 to 1.5, where Ws is a maximum W amount in the surface region and Wi is an internal W amount in the internal region. The area ratios A1, A2, and A3 of the respective hard phases are from 75 to 95 area % for A1, from 4 to 24 area % for A2, and from 1 to 24 area % for A3.

A core drill bit can include a first region and a second region. The first region can include abrasive particles in a first bond matrix, and the second region can include abrasive particles in a second bond matrix. The first region is connected to the second region. A composition of the first bond matrix can be different from a composition of the second matrix. In a particular embodiment, the first bond matric can include a Co-containing material.

A cermet tool includes from 75-95 volume % of a hard phase and from 5-25 volume % of a binder phase. The hard phase has a first hard phase with a core portion of (Ti, Nb, Mo) (C, N) and a peripheral portion of (Ti, Nb, Mo, W) (C, N) or (Ti, Nb, Mo, W, Zr) (C, N), a second hard phase with both a core portion and a peripheral portion of (Ti, Nb, Mo, W) (C, N) or (Ti, Nb, Mo, W, Zr) (C, N), and a third hard phase of (Ti, Nb, Mo) (C, N). The ratio of Nbs/Nbi is from 0.8 to 1.2, where Nbs is a maximum Nb amount in a surface region and Nbi is an internal Nb amount in an internal region. The ratio of Ws/Wi is from 1.0 to 1.5, where Ws is a maximum W amount in the surface region and Wi is an internal W amount in the internal region. The area ratios A1, A2, and A3 of the respective hard phases are from 75 to 95 area % for A1, from 4 to 24 area % for A2, and from 1 to 24 area % for A3.