A rotatable cutting tool has a cutting tool body having at least one recess for receiving a replaceable insert. The recess has a wall defined by a deformable clamp extending radially from the tool body, the clamp having a leaf isolated from the tool body except at the base of the leaf by an isolating channel in the tool body. The tool further has an adjustable leaf-bending element for elastically deforming the leaf to retain a replaceable insert in the recess.