This invention relates to a ground drilling or cutting tool comprising a cutting element removably attached thereto by attachment means, the tool further including retention means adapted to maintain attachment of the cutting element to the tool in the event that the attachment means fails. The retention means comprises a first surface on a side of the cutting element, a mounting recess in the cutting tool in which at least a portion of said cutting element locates, a second surface in a side of the mounting recess against which said first surface locates, channels in each of said first and second surfaces that align so as to cooperatively define a dowel hole when said first and second surfaces locate together, at least one dowel that locates in the dowel hole, and means for retaining the or each dowel within the dowel hole.