The BullseyeBore is a nifty drill attachment that uses lasers to tell you if you’re drilling straight. The attachment can be affixed to any drill and works in any orientation (wall, floor, ceiling etc.). The laser projections even provide visual cues on drill bit depth.
There are three patterns generated by BullseyeBore: a single dynamic position pattern, and two fixed circular measurement patterns. The single dynamic position pattern changes shape dramatically when the drill is misaligned with the work surface, while the two fixed measurement patterns maintain consistent and evenly spaced concentric circles regardless of alignment.
A drill is properly aligned with the work surface when the single position pattern becomes circular and is concentric with the two fixed measurement patterns. [source]
After a drill is aligned and pressed into the work surface, the circle produced by the single dynamic position pattern becomes smaller. The change in the circle’s diameter is equal to the depth that the drill bit has penetrated into the work surface.
For example, if the diameter of the circular position pattern is 4.0 inches at the start of a drilling operation, and the ending diameter is 3.5 inches, then the drill bit has penetrated 0.5 inches into the work surface.
The two measurement patterns assist in this process by providing stationary and evenly spaced concentric circles that can be used as reference points to track the size change of the position pattern circle. [source]
The version seen here is a small transparent disk with a hex-shank quick-change connector. The lasers, optics and batteries are all mounted inside the disk.
For more information on this patented device check out the official website at bullseyebore.com