Abstract: A portable core drill adapted for sampling dense mineral specimens or the like by urging a fluid cooled/lubricated tubular drill bit into a dense mineral mass from which a sample is to be extracted is comprised of a drive member for imparting a drilling-effective rotary motion to a tubular drill bit about a longitudinal drill axis and a spindle member for coupling the drill bit to the drive member, which spindle member includes a bit fastening member for receiving and retaining the drill bit concentrically in respect of the drill axis.