Cutting apparatus

A cutter for a cutting unit used in cutting apparatus suitable for creating tunnels or subterranean roadways, said cutter comprising:

• a disc body having an underside, an upper side arranged substantially opposite to the underside, a central axis, and a radially peripheral part, wherein the underside of the disc body is recessed to reduce frictional engagement between the disc body and a rock face during an undercutting operation;
• and
• a plurality of buttons for abrading rock, said buttons being mounted in the radially peripheral part of the disc body and protruding outwardly therefrom to engage rock during an undercutting operation, wherein at least some of the buttons have a cutting part having a dome-shaped cutting surface, the radially peripheral part including a first annular tapering surface and a second annular tapering surface, each of the first and second annular tapering surfaces having a lower edge, the second annular tapering surface tapering downwardly and inwardly from the lower edge of the first tapering surface to its lower edge, wherein the underside of the disc body has an annular tapering surface that tapers inwardly and upwardly from the lower edge of the second annular tapering surface to an upper edge of the disc body annular tapering surface, such that the disc body annular tapering surface has a maximum diameter at the lower edge of the second annular tapering surface and a minimum diameter at the upper edge thereof as measured from the central axis, wherein at least some of the buttons each have a central longitudinal axis that subtends an angle α with respect to a first reference axis, which extends perpendicularly outwards from the central axis of the body, wherein 20°≤α≤34°, wherein the annular tapering surface subtends an γ with respect to a second reference axis, which extends perpendicularly outwardly from the central axis, wherein 2°≤γ≤20°, and wherein the first annular tapering surface subtends an angle β with a third reference axis that is parallel to the central axis of the body, wherein 5°≤β.