A rotatable cutting tool having a longitudinal axis about which the rotary cutting tool is rotatable in a direction of rotation, the rotatable cutting tool comprising: a front end and an opposite rear end, the front end comprising a front end face surface; a cutting portion extending from the front end and a mounting portion extending from the rear end, the cutting portion comprising the front end face surface, intersected by the longitudinal axis, and a peripheral surface extending from the front end face surface towards the mounting portion, the peripheral surface comprising: first helical flutes extending from the front end to a first helical flute rear end, second helical flutes extending from a second helical flute front end to a second helical flute rear end, at least one of the second helical flutes intersects with at least one of the first helical flutes at a portion located between the first helical flute rear end and the second helical flute front end; the second helical flute front end, the first helical flute rear end, and the second helical flute rear end each is at an axial distance greater than zero from the front end, wherein first helical cutting edges are formed between adjacent pairs of first helical flutes; wherein second helical cutting edges are formed between adjacent pairs of second helical flutes; wherein third cutting edges are formed between adjacent pairs of first helical flutes and adjacent pairs of second helical flutes; wherein the first helical flutes and the second helical flutes are of opposite hands, wherein the first helical flutes are helically aligned about the longitudinal axis and form a first helix angle (α); wherein the second helical flutes are helically aligned about the longitudinal axis and form a second helix angle (β); wherein a first core diameter is defined by a diameter the first helical flutes; wherein a second core diameter is defined by the second helical flutes; characterised in that the first helix angle (α) is decreasing in absolute value away from the front end and/or that the second helix angle (β) is increasing in absolute value away from the front end. a front end and an opposite rear end, the front end comprising a front end face surface; a cutting portion extending from the front end and a mounting portion extending from the rear end, the cutting portion comprising the front end face surface, intersected by the longitudinal axis, and a peripheral surface extending from the front end face surface towards the mounting portion, the peripheral surface comprising: first helical flutes extending from the front end to a first helical flute rear end, second helical flutes extending from a second helical flute front end to a second helical flute rear end, at least one of the second helical flutes intersects with at least one of the first helical flutes at a portion located between the first helical flute rear end and the second helical flute front end; the second helical flute front end, the first helical flute rear end, and the second helical flute rear end each is at an axial distance greater than zero from the front end, wherein first helical cutting edges are formed between adjacent pairs of first helical flutes; wherein second helical cutting edges are formed between adjacent pairs of second helical flutes; wherein third cutting edges are formed between adjacent pairs of first helical flutes and adjacent pairs of second helical flutes; wherein the first helical flutes and the second helical flutes are of opposite hands, wherein the first helical flutes are helically aligned about the longitudinal axis and form a first helix angle (α); wherein the second helical flutes are helically aligned about the longitudinal axis and form a second helix angle (β); wherein a first core diameter is defined by a diameter the first helical flutes; wherein a second core diameter is defined by the second helical flutes; characterised in that the first helix angle (α) is decreasing in absolute value away from the front end and/or that the second helix angle (β) is increasing in absolute value away from the front end. first helical flutes extending from the front end to a first helical flute rear end, second helical flutes extending from a second helical flute front end to a second helical flute rear end, at least one of the second helical flutes intersects with at least one of the first helical flutes at a portion located between the first helical flute rear end and the second helical flute front end; the second helical flute front end, the first helical flute rear end, and the second helical flute rear end each is at an axial distance greater than zero from the front end, wherein first helical cutting edges are formed between adjacent pairs of first helical flutes; wherein second helical cutting edges are formed between adjacent pairs of second helical flutes; wherein third cutting edges are formed between adjacent pairs of first helical flutes and adjacent pairs of second helical flutes; wherein the first helical flutes and the second helical flutes are of opposite hands, wherein the first helical flutes are helically aligned about the longitudinal axis and form a first helix angle (α); wherein the second helical flutes are helically aligned about the longitudinal axis and form a second helix angle (β); wherein a first core diameter is defined by a diameter the first helical flutes; wherein a second core diameter is defined by the second helical flutes; characterised in that the first helix angle (α) is decreasing in absolute value away from the front end and/or that the second helix angle (β) is increasing in absolute value away from the front end.