A drill pipe mountable wellbore cleaning tool apparatus is of an improved configuration that enables attachment to a drill pipe joint having first and second connector end portions and a cylindrically shaped portion in between the connector end portions. The drill pipe joint with attached debris cleaning tool or tools is made part of a drill string. The apparatus includes a support sleeve that is mounted to the drill pipe joint in between the connector end portions. The support sleeve abuts but does not invade the integrity of the cylindrical portion. Centralizers are attached to the opposing ends of the support sleeve, with each centralizer overlapping a portion of the support sleeve. The support sleeve carries one or more debris cleaning tools in between the centralizers. These tools enable debris to be removed from a wellbore. At least one locking clamp is attached to the cylindrical portion next to a said centralizer. The locking clamp prevents the support sleeve from moving longitudinally along the drill pipe joint.