Abstract: The invention is directed to a guide for a power saw or router of the type having a blade and a housing wider than the blade which directly overlies the blade during the cutting operation. The guide includes a guide bar having a straight outer edge configured for guiding a peripheral edge of the saw housing and a gauge device. The gauge device includes an elongated holder and a light beam projector mounted on the holder for projecting a beam of light at an angle relative to a lengthwise axis of the holder. In this respect, the light beam projector is mounted on the holder for projecting a beam of light at a right angle relative to a lengthwise axis of the holder such that the beam of light is parallel to the straight outer edge of the guide bar. The light beam projector is preferably a laser.

Abstract: The invention is directed to a guide for a power saw or router of the type having a blade and a housing wider than the blade which directly overlies the blade during the cutting operation. The guide includes a guide bar having a straight outer edge configured for guiding a peripheral edge of the saw housing and a gauge device. The gauge device includes an elongated holder and a light beam projector mounted on the holder for projecting a beam of light at an angle relative to a lengthwise axis of the holder. In this respect, the light beam projector is mounted on the holder for projecting a beam of light at a right angle relative to a lengthwise axis of the holder such that the beam of light is parallel to the straight outer edge of the guide bar. The light beam projector is preferably a laser.

Abstract: In a method for making a self-propelled impact boring tool, the tool body is formed by swaging a steel tube to form the tapered nose of the tool. This results in less wasted steel as compared to conventional machining of a solid steel bar to form the body, which is the largest single part of the tool. The tool body may then be fitted with a tool anvil of slightly different dimensions than the forming anvil used during swaging to provide an interference fit.

Abstract: A pneumatic ground piercing tool has a head which can be removed and replaced with a replacement head of the same or different design. The detachable head is mounted on the an axial rod behind a threaded surface of the rod, and a nut is threadedly secured on the front threaded portion of the rod, whereby the head is clamped between a front end of the tool housing and the nut. The nut can be unscrewed from the rod to permit replacement of the head. A clamp-loading locking mechanism is used to secure the head to the nut to prevent the nut and head from loosening during operation.

Abstract: The weight of a pneumatic ground piercing tool of the type having a stepped air inlet is reduced and tool power increased by providing the tool body with a dual diameter. The tubular tool body has a front section and a rear section which has a greater inner and outer diameter than the front section, thereby reducing overall tool weight. In a preferred embodiment, the rear end portion of the striker likewise has a greater outer diameter than the front end portion thereof. The bearing of the front end portion of the striker remains in sliding contact with the interior of the front body section during tool operation, and the bearing of the rear end portion of the striker likewise remains in sliding contact with the interior of the rear body section. In this manner, the power of the tool is enhanced because the tool has less weight and the air distributing mechanism, located in the rear body section, is the same size as in a conventional tool wherein the entire body has a uniform diameter.

Abstract: In a method for making a self-propelled impact boring tool, the tool body is formed by swaging a steel tube to form the tapered nose of the tool. This results in less wasted steel as compared to conventional machining of a solid steel bar to form the body, which is the largest single part of the tool. The tool body may then be fitted with a tool anvil of slightly different dimensions than the forming anvil used during swaging to provide an interference fit.

Abstract: The present invention provides a self-propelled impact boring tool which, according to one aspect of the invention, has a simplified tail assembly so that the tool can be readily assembled and dissambled to allow replacement of worn parts. Such a tail assembly includes a nut and an end cap which can be secured together by a series of conventional bolts which extend into threaded holes in the nut. The nut, which is screwed into the rear end of the tool body, can be clamped in position with the screws with far less torque than would otherwise be required with a conventional, unitary tailpiece.

Abstract: A method for inhibiting roadbed erosion and damage to roadways utilizes an underdrain system for removing water which causes such damage. Underdrains in the form of perforate pipes, preferably covered with a geotextile sock as a filter, are disposed transversely to the lengthwise direction of the roadway in close proximity to faults, cracks, joints and other fissures in the roadway. The underdrains conduct water away from such fissures thereby preventing roadbed particulate material from being pumped upwardly through the fissures together with water which collects below the concrete roadway. Such an installation is highly useful for preventing further damage to existing roadways, and may be installed without interrupting traffic or destroying the road surface by means of a pneumatic underground piercing tool.