Abstract: Apparatus for cleaning scale, sludge, rust, concrete, or other unwanted material from the interior walls of sections of pipe, the apparatus including a honing tool which is insertable and rotatable in a section of pipe clamped on a transportable primary carrier, and has at its end a cutting tool with a pair of arcuate cutting edges to provide a desirable tangential contact with the pipe, and to facilitate cleaning of slightly bent pipes. The tool also has two pairs of diametrically opposed cutting elements resiliently mounted on the tool shank and urged outwardly in a self-centering action. The tool is mounted on a shaft which is loosely journaled on a secondary carrier, to provide tool flexibility and a desirable whipping action, and the secondary carrier can be telescoped into the primary carrier for transportation purposes. A hydraulic motor for driving the tool shaft is mounted on a carriage which can be translated linearly on the secondary carrier, to advance the tool into the clamped pipe section.