Editing Laser line level

{{Verification|date=November 2023}}{{distinguish|Laser level}}
[[Image:Laser line level.jpg|thumb|150px|Typical consumer laser line level using [[spirit level]]s for three planes and including a digital stud sensor display.]]

A '''laser line level''' is a tool combining a [[spirit level]] and/or [[plumb bob]] with a [[laser]] to display an accurately horizontal or vertical illuminated line on a surface the laser line level is laid against. Laser line levels are used wherever accurate verticals and horizontals are required, typically in the [[construction]] and [[Cabinet (furniture)|cabinetry]] industries. Some models are inexpensive enough for [[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 machine is 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 millimetres per metre or fractions of an inch over a specified distance in feet. A more advanced device may be accurate to within 0.3&nbsp;mm/m; while lower-end models may be closer to 1.5&nbsp;mm/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 [[Wood warping|warp]]ed, even if not horizontal.

==See also==
* [[Dumpy level]]
* [[Theodolite]]
* [[List of laser articles]]
* [[Laser Machine Control]]

==References==
{{Measuring and alignment tools}}

[[Category:Construction equipment]]
[[Category:Construction surveying]]
[[Category:Laser applications]]
[[Category:Surveying instruments]]
[[Category:Woodworking measuring instruments]]