The present invention comprises a drilling tool for attachment to conventional drilling means, which roughens the internal surface of a pre-drilled hole to enhance attachment of an anchoring device and adhesive placed therein. The roughening device has a shaft for attaching to a conventional drilling device at one end and a tubular side wall bearing cutters/abraders at the other. There is a void between the shaft and the side wall which is filled by an elastomeric material which cushions the action of the cutters/abraders.