Abstract: A cutting tool is designed to cut through plastic pipe from within. This operation is required when a pipe is mounted in a floor or wall and must be cut off below the level of the floor for installation of plumbing fixtures. A rotary shaft with a rotary saw blade at one end is adapted for rotating in an electric drill at a second end. The shaft is journaled in a sleeve. A locking collar is slideably mounted on the sleeve. The collar is locked on the sleeve at a particular level so that when the underside of the collar engages the cut end of the exposed pipe, the blade will cut the wall at the desired depth. The collar is kept in contact with the pipe end as the sleeve is moved in a circle against the inside of the pipe so that the inside cut will be at a uniform depth.