A drill bit jig includes an elongate member, two jig securing elements and a drill bit guide. The drill bit guide includes a plurality of through holes where the axes of the through holes are parallel to the axis of the elongate member. Each of the plurality of through holes in the drill bit guide has a different diameter for accommodating drill bits of different thicknesses. The jig securing elements each include an L-shaped bolt and a door protecting material encasing one of the straight sections of the bolt. The drill bit jig also includes a core check to determine if a hole being drilled along the width of the door is straight.