A turning tool comprising a tool body and a turning insert, wherein the turning insert comprises a top surface, an opposite bottom surface, a reference plane between the top and bottom surfaces (2, 3), a center axis intersecting the top and bottom surfaces (2, 3), a side surface connecting the top surface and the bottom surface, a cutting edge adjacent to the top surface and the side surface, the cutting edge being circular and concentric in relation to the center axis, wherein the bottom surface of the turning insert comprises a set of flat surfaces, wherein the flat surfaces extend in a plane parallel to the reference plance, wherein the turning tool comprises an insert seat, wherein the insert seat comprises a bottom surface, wherein the bottom surface of the insert seat comprises a support surface (21, 32), wherein the turning insert is mounted in the insert seat by means of a clamping device, wherein the insert seat comprises a rear surface, wherein the side surface of the turning insert is in contact with the rear surface of the insert seat, wherein the bottom surface of the turning insert comprises a set of radial grooves, wherein the radial grooves intersect the side surface, wherein the bottom surface of the insert seat comprises a first ridge, wherein the support surface (21, 32) of the insert seat is planar, wherein the first ridge is inside one of the radial grooves formed in the bottom surface of the turning insert, wherein at least one of the flat surfaces of the turning insert is in contact with the support surface (21, 32) of the insert seat, wherein in a cross section, the first ridge is smaller than one of the radial grooves, wherein the tool body comprises a coupling portion, wherein the coupling portion extends along a longitudinal axis of the turning tool, characterized in that wherein the bottom surface of the insert seat comprises a second ridge, wherein the first ridge and the second ridge are aligned, wherein the first ridge extends primarily along or parallel to the longitudinal axis of the turning tool, wherein the bottom surface of the insert seat comprises two support surfaces (21, 32), and wherein the support surfaces (21, 32) are located in a common plane, wherein in a top view, an area of the support surfaces (21,32) are greater than an area of the ridge or ridges (18,24), and wherein all of the flat surfaces of the turning insert are in contact with the support surfaces (21,32). an opposite bottom surface, a reference plane between the top and bottom surfaces (2, 3), a center axis intersecting the top and bottom surfaces (2, 3), a side surface connecting the top surface and the bottom surface, a cutting edge adjacent to the top surface and the side surface, the cutting edge being circular and concentric in relation to the center axis, wherein the bottom surface of the turning insert comprises a set of flat surfaces, wherein the flat surfaces extend in a plane parallel to the reference plance, wherein the turning tool comprises an insert seat, wherein the insert seat comprises a bottom surface, wherein the bottom surface of the insert seat comprises a support surface (21, 32), wherein the turning insert is mounted in the insert seat by means of a clamping device, wherein the insert seat comprises a rear surface, wherein the side surface of the turning insert is in contact with the rear surface of the insert seat, wherein the bottom surface of the turning insert comprises a set of radial grooves, wherein the radial grooves intersect the side surface, wherein the bottom surface of the insert seat comprises a first ridge, wherein the support surface (21, 32) of the insert seat is planar, wherein the first ridge is inside one of the radial grooves formed in the bottom surface of the turning insert, wherein at least one of the flat surfaces of the turning insert is in contact with the support surface (21, 32) of the insert seat, wherein in a cross section, the first ridge is smaller than one of the radial grooves, wherein the tool body comprises a coupling portion, wherein the coupling portion extends along a longitudinal axis of the turning tool, characterized in that wherein the bottom surface of the insert seat comprises a second ridge, wherein the first ridge and the second ridge are aligned, wherein the first ridge extends primarily along or parallel to the longitudinal axis of the turning tool, wherein the bottom surface of the insert seat comprises two support surfaces (21, 32), and wherein the support surfaces (21, 32) are located in a common plane, wherein in a top view, an area of the support surfaces (21,32) are greater than an area of the ridge or ridges (18,24), and wherein all of the flat surfaces of the turning insert are in contact with the support surfaces (21,32).