A tool comprising a burr cutter 34 and a guide 2, the guide 2 comprising: a body portion 4 having first and second guide surfaces 12a, 12b which are spaced from one another to define a slot 14 between the first and second guide surfaces 12a, 12b; a bearing 32a, 32b for rotatably mounting the body portion 4 to a shank 38 of the burr cutter 34 with a cutting head 36 of the burr cutter 34 adjacent the slot 14; wherein the first and second guide surfaces 12a, 12b and the bearing 32a, 32b are positioned relative to one another such that the first and second guide surfaces 12a, 12b are tangential to the cutting head 36 of the burr cutter 34.