A cutting device for use with a portable power tool including a driving means, wherein the cutting device includes: a working element, a movement transfer mechanism linking to the working element, the movement transfer mechanism including: a movement transfer block, a drive shaft configured to be linked to a driving means, wherein the drive shaft includes a head with an offset pin configured to engage with the movement transfer block, a linking arm, wherein the linking arm has a first end linked to the working element and a second end configured to engage with the movement transfer block, wherein the movement transfer block includes a first aperture or recess substantially inline with the linking arm of the working element and configured to slideably receive the second end of the linking arm, and a second aperture or recess substantially inline with, and configured to slideably receive, the pin of the head of the drive shaft, with the first and second apertures (11,12) of the movement transfer block being substantially perpendicular to each other, characterised in that the working element is a cutting assembly having at least a cylindrical inner blade and a cylindrical outer blade arranged concentrically inside each other. a working element, a movement transfer mechanism linking to the working element, the movement transfer mechanism including: a movement transfer block, a drive shaft configured to be linked to a driving means, wherein the drive shaft includes a head with an offset pin configured to engage with the movement transfer block, a linking arm, wherein the linking arm has a first end linked to the working element and a second end configured to engage with the movement transfer block, wherein the movement transfer block includes a first aperture or recess substantially inline with the linking arm of the working element and configured to slideably receive the second end of the linking arm, and a second aperture or recess substantially inline with, and configured to slideably receive, the pin of the head of the drive shaft, with the first and second apertures (11,12) of the movement transfer block being substantially perpendicular to each other, characterised in that the working element is a cutting assembly having at least a cylindrical inner blade and a cylindrical outer blade arranged concentrically inside each other. a movement transfer block, a drive shaft configured to be linked to a driving means, wherein the drive shaft includes a head with an offset pin configured to engage with the movement transfer block, a linking arm, wherein the linking arm has a first end linked to the working element and a second end configured to engage with the movement transfer block, wherein the movement transfer block includes a first aperture or recess substantially inline with the linking arm of the working element and configured to slideably receive the second end of the linking arm, and a second aperture or recess substantially inline with, and configured to slideably receive, the pin of the head of the drive shaft, with the first and second apertures (11,12) of the movement transfer block being substantially perpendicular to each other, characterised in that the working element is a cutting assembly having at least a cylindrical inner blade and a cylindrical outer blade arranged concentrically inside each other.