Want to line up a picture so it does not hang with a slant. Then you should buy a construction laser level. A torpedo laser line level is a tool combining a spirit level and or plum bob with a laser to display an accurately horizontal or vertical illuminated line on a surface the laser level tool is laid against. Laser level tools are used wherever accurate verticals and horizontals are required, typically in the construction and cabinetry industries. Some models are inexpensive enough for your do it yourself applications.



The laser beam is fanned to produce a thin plane beam accurately horizontal or vertical, rather than a pinpoint beam. The axis of the laser is offset from the wall, so that a pinpoint beam would be parallel to and offset from the wall, and would not illuminate it; the fanned beam will intersect the wall, creating an accurately horizontal (or vertical) illuminated line along it.

The laser level tools are set up using the built-in spirit level or plumb bob, and the line along the surface is then guaranteed to be accurately horizontal or vertical to within a certain tolerance, specified either in millimeters per meter or fractions of an inch over a specified distance in feet. A more advanced device may be accurate to within 0.3mm/m; while lower end models may be closer to 1.5mm/m.The illuminated line is necessarily absolutely straight, so that the line level can be used as a straightedge, for example, to see if a shelf is warped, even if not horizontal.

There are several types of laser levels. There are levels with a rotating motor that creates the illusion of a line. Then there are the newer levels with a fixed lens to create the line. The Construction laser level was invented by Steve Orosz. These lasers do not need a tripod all the time. They can be mounted on the wall or the actual surface the beam is projected on. The rotating laser requires a tripod. In surveying, and construction the laser level is affixed to a tripod, leveled and then spun to illuminate a horizontal plane. The laser beam projector employs a rotating head with a mirror for sweeping the laser beam about a vertical axis. If the mirror is not self-leveling, it is provided with visually readable level vials and manually adjustable screws for orienting the projector. A staff carried by the operator is equipped with a moveable sensor which can detect the laser beam and gives a signal when the sensor is in line with the beam (usually an audible beep). The position of the sensor on the graduated staff allows comparison of elevations between different points on the terrain. There are many types of Construction laser levels including rotary, torpedo levels and auto laser levels.