A cutting tool assembly (100, 200, 300), comprising a tool holder (102, 202, 302) whose longitudinal holder axis extends in a rearward to forward direction (D R, D F), a tool head (104, 204, 304) whose longitudinal tool head axis extends in the rearward to forward direction (D R, D F) and a tool head fastening member, wherein an upward-downward direction (U, D) is substantially perpendicular to the holder axis, characterised in that the tool holder (102, 202, 302) includes a holder front end, a holder top end, a holder mating surface (114, 314) extending therebetween, and a holder clamping portion spaced apart in the rearward direction (D R) from the holder mating surface (114, 314); wherein the tool head (104, 204, 304) includes a tool head bottom end provided with a tool head mating surface (132, 316), and a tool head rearward surface provided with a tool head clamping recess extending upwards from the tool head bottom end; and wherein in an assembled position of the cutting tool assembly (100, 200, 300): the tool head mating surface (132, 316) forms a dovetail connection with the holder mating surface (114, 314); and the tool head fastening member clamps the tool head clamping recess, thereby externally clamping the tool head (104, 204, 304) to the tool holder (102, 202, 302), wherein the holder mating surface (114, 314) includes a plurality of holder mating sidewalls (140, 310), and the tool head mating surface (132, 316) includes a plurality of tool head mating sidewalls (138,312) conforming to the holder mating sidewalls (140, 310), wherein: • the holder mating surface includes a female portion partially limited by the holder mating sidewalls and the tool head mating surface includes a male portion partially limited by the tool head mating sidewalls, or • the holder mating surface includes a male portion partially limited by the holder mating sidewalls, and the tool head mating surface includes a female portion partially limited by the tool head mating sidewalls, wherein the holder mating surface (114, 314) is tilted by an acute tilt angle (δ) relative to the holder axis in a view perpendicular to the rearward to forward direction (D R, D F) and to the upward-downward direction (U, D), and wherein the tool head mating surface (132, 316) is tilted by an acute tilt angle (δ) relative to the tool head axis in a view perpendicular to the rearward to forward direction (D R, D F) and to the upward-downward direction (U,D). a tool holder (102, 202, 302) whose longitudinal holder axis extends in a rearward to forward direction (D R, D F), a tool head (104, 204, 304) whose longitudinal tool head axis extends in the rearward to forward direction (D R, D F) and a tool head fastening member, wherein an upward-downward direction (U, D) is substantially perpendicular to the holder axis, characterised in that the tool holder (102, 202, 302) includes a holder front end, a holder top end, a holder mating surface (114, 314) extending therebetween, and a holder clamping portion spaced apart in the rearward direction (D R) from the holder mating surface (114, 314); wherein the tool head (104, 204, 304) includes a tool head bottom end provided with a tool head mating surface (132, 316), and a tool head rearward surface provided with a tool head clamping recess extending upwards from the tool head bottom end; and wherein in an assembled position of the cutting tool assembly (100, 200, 300): the tool head mating surface (132, 316) forms a dovetail connection with the holder mating surface (114, 314); and the tool head fastening member clamps the tool head clamping recess, thereby externally clamping the tool head (104, 204, 304) to the tool holder (102, 202, 302), the tool head mating surface (132, 316) forms a dovetail connection with the holder mating surface (114, 314); and the tool head fastening member clamps the tool head clamping recess, thereby externally clamping the tool head (104, 204, 304) to the tool holder (102, 202, 302), wherein the holder mating surface (114, 314) includes a plurality of holder mating sidewalls (140, 310), and the tool head mating surface (132, 316) includes a plurality of tool head mating sidewalls (138,312) conforming to the holder mating sidewalls (140, 310), wherein: • the holder mating surface includes a female portion partially limited by the holder mating sidewalls and the tool head mating surface includes a male portion partially limited by the tool head mating sidewalls, or • the holder mating surface includes a male portion partially limited by the holder mating sidewalls, and the tool head mating surface includes a female portion partially limited by the tool head mating sidewalls, • the holder mating surface includes a female portion partially limited by the holder mating sidewalls and the tool head mating surface includes a male portion partially limited by the tool head mating sidewalls, or • the holder mating surface includes a male portion partially limited by the holder mating sidewalls, and the tool head mating surface includes a female portion partially limited by the tool head mating sidewalls, wherein the holder mating surface (114, 314) is tilted by an acute tilt angle (δ) relative to the holder axis in a view perpendicular to the rearward to forward direction (D R, D F) and to the upward-downward direction (U, D), and wherein the tool head mating surface (132, 316) is tilted by an acute tilt angle (δ) relative to the tool head axis in a view perpendicular to the rearward to forward direction (D R, D F) and to the upward-downward direction (U,D).