US Patent 7094008 Power driver bit self-centering and positioning apparatus

A portable combined clamp and bit guide assembly guides a bit, turned by a power driver, into the exact center between the opposing faces of the clamp. The clamp is designed to hold workpieces having substantially parallel edges and a substantially linear centerline on their upper surfaces, and provides a drill path perpendicular to that centerline. An optional incline adapter supports the clamp and bit guide at an angle to the workpiece, while also aiding in support of the workpiece itself. The entire assembly may be carried in a single case with a power driver and bits.