Abstract: A system for removing failed fasteners from structures removes the head of the fastener in a controlled manner with precise support and alignment for the cutting tool. A drill guide, drill bushings and the cutting tool mount virtually anywhere on an underlying structure using existing fasteners and receptacles formed in the structure. This design permits the drill guide to be rigidly attached to the structure so that the cutting tool can be positioned and supported directly over the failed fastener. After the drill guide is mounted, a drill bit is extended through the drill bushing to drill a pilot hole in the failed fastener. The cutting tool is used through the drill bushing to cut off the head of the failed fastener without contacting the surrounding structure. All operations required to remove the failed fastener are accomplished through the drill bushings contained in the mounted drill guide.

Abstract: A pneumatic feed drill has a control unit that repeatedly advances and retracts the drill bit in peck cycles while drilling the hole. The drill has a hydraulic damper cylinder with a damper rod protruding from it that limits the speed of advancement of the drill bit. A retainer device is mounted to the damper rod and prevents the damper rod from resetting to its initial position during the peck cycles. The retainer device releases the damper rod to reset when the drill bit has reached total depth. A safety device is pivotally mounted to the housing and has a closure tab that blocks access to the start button of the drill unless the damper rod is in its initial position.

Abstract: A system for removing failed fasteners from structures removes the head of the fastener in a controlled manner with precise support and alignment for the cutting tool. A drill guide, drill bushings and the cutting tool mount virtually anywhere on an underlying structure using existing fasteners and receptacles formed in the structure. This design permits the drill guide to be rigidly attached to the structure so that the cutting tool can be positioned and supported directly over the failed fastener. After the drill guide is mounted, a drill bit is extended through the drill bushing to drill a pilot hole in the failed fastener. The cutting tool is used through the drill bushing to cut off the head of the failed fastener without contacting the surrounding structure. All operations required to remove the failed fastener are accomplished through the drill bushings contained in the mounted drill guide.

Abstract: A pneumatic feed drill has a control unit that repeatedly advances and retracts the drill bit in peck cycles while drilling the hole. The drill has a hydraulic damper cylinder with a damper rod protruding from it that limits the speed of advancement of the drill bit. A retainer device is mounted to the damper rod and prevents the damper rod from resetting to its initial position during the peck cycles. The retainer device releases the damper rod to reset when the drill bit has reached total depth. A safety device is pivotally mounted to the housing and has a closure tab that blocks access to the start button of the drill unless the damper rod is in its initial position.