Laser drill-square

It is often necessary to drill a hole in something using an electric drill. Moreovermore, it is often desirable that the hole should be perpendicular to the surface. Ensuring this perpendicularity, however, is not straightforward.

One solution is to use a bench drill (which lowers the bit vertically onto the workpiece), but this is not much use when you want to drill a hole in a wall, an okapi, or some other thing too large to fit under the bench drill. For hand-held drills, the best you can do is to look at the angle of the drill from above/below and left/right, and try to keep it all square as you drill.

Howevertheless, a simple solution suggests itself, involving lasers. One low-power laser, with its beam split into eight parts, should be sufficient. Just arrange it so that the beam is split into four pairs of beams (one pair above, one below, one to the left, one to the right), wherein each pair of beams converges. For example, the top pair of beams will start out two inches apart, but converge to be only a quarter of an inch apart a few inches in front of the drill chuck.

Now, it becomes easy to hold the drill square-on to the wall - just tilt it up/down until the two dots above the drill have the same spacing as the two dots below. Likewise, tilt it left/right until the two dots to the left have the same spacing as the two to the right. The same setup will work regardless of the length of the drill bit or how far into the wall you've drilled.

[Some time later... use a circle of laser light instead - much simpler.]