Abstract: A rotatable cutting tool for mounting in the bore of a block comprising an elongate symmetrical body having forward and rearward portions wherein the forward portion terminates in a front end at which there is a cutting tip and the rearward portion is of a generally constant diameter and terminates in a rear end. The rearward portion contains a channel adjacent the rear end. A resilient retainer surrounds substantially all of the rearward portion and extends rearwardly past the rear end. The retainer has an inward projection which is received within the channel so that the elongate body and retainer are retained together. The retainer has an unstressed diameter greater than the diameter of the bore so that when the cutting tool is inserted into the bore the retainer expands against the bore so as to be held therein whereby the body is free to rotate relative to the block.