Abstract: A wall contacting tool, such as a fixed blade rotating stabilizer, useful in earth boring has replaceable wear pads. Each pad is of generally sector shape cross section, the pad corner having a 90.degree. apex angle and fitting in a correlative V groove flute at the end of an arm of the stabilizer body, being held in place by radial dowel pins each bisecting the apex angle of the corner and flute. Each pin has a head turned to be retained in a slot in the body and having a threaded socket receiving a cap screw whose head engages an outwardly facing shoulder in a stepped hole in the pad. The pad corner above and below the dowel pin locks the dowel pin head against turning. A releasable retainer ring in an annular groove in the stepped hole prevents withdrawal of the cap screw from the pad. A lateral dowel inbetween one side of the pad corner and one side of the body flute prevents movement of the pad radially outwardly from the flute.

Abstract: A drilling fluid roller reamer-stabilizer includes a tubular body having threaded pin and box connectors at each end adapted to be connected in a drill string and providing a fluid passage connecting the upper part of the drill string with the lower part. Rollers having integral pins at their ends are mounted in pockets in the sides of the body. The pins extend into holes in arcuate cross section bearing blocks received in correlative sockets in the body at the ends of the pockets. Each block makes an interference fit with the sockets in the body. Tool access passages allow a tool to be inserted behind each block to drive or pry it out. Slotted, resilient bearing sleeves are provided in the holes in the blocks where the roller pins are received. The sleeves extend beyond the holes toward the rollers to take axial thrust. Flanges on the ends of the sleeves provide additional thrust area.

Abstract: An earth boring drill employing roller cutters is provided with a seal in a peripheral groove to inhibit ingress of detritus into the cutter bearing area and egress of lubricant therefrom. The shape of the seal is such that its cross section is not overly compressed or displaced when in operating position, thus preventing undue compression set, wear and heating of the seal. A preferred seal has a greater radial dimension than axial dimension by a ratio of at least one-and-one-half to one to conserve bearing space and to provide the necessary flexibility to accommodate the various movements of the cutter relative to the shaft upon which it is rotatably mounted. The roller cutter has a counterbore fitting over a short cylindrical boss from which the shaft extends on which the cutter is mounted. This provides a tortuous passage restricting ingress of detritus and substantially improved life of the drill bit.