measure true horizontal (level) and true vertical (plumb) either with
vials (spirit levels) or sensors (electronic levels). These mechanisms
are incorporated into rails of wood, plastic, aluminum or magnesium. The
rail or body of the level may be solid, I-beam or box-beam.
grades of levels are determined by the strength and rigidity of the frame,
and the type and accuracy of the vials or other measuring device. Level
vials may be adjustable or nonadjustable, straight or bent, replaceable
or permanent. Some vials are constructed of a precision-tapped block of
solid acrylic and are virtually unbreakable.
the level is laid on an object or surface, or placed against an object
or surface, the location of the bubble tells you whether or not the object,
or surface, is level. If the bubble floats to the middle of the vial,
then it is level. But, if the bubble floats to the left side, that means
the object is low on the left side. On the other hand, if the bubble floats
to the right side, that means the object is low on the right side.
Electronic levels employ sensors rather than vials. One uses an audio
signal or colored lights to indicate level and plumb, another includes
a visual display. More sophisticated models read angles as well as level
and plumb, and offer a reset button so the level can be recalibrated if
Levels come with both adjustable and nonadjustable vials. Wood levels
use epoxy or cement to hold vials in place. Accidental damage can knock
vials out of adjustment. Levels with replaceable vials provide on-the-spot
serviceability in the event a vial is accidentally damaged.
Better wood levels come with brass or aluminum edges. These edges prevent
chipping and help to protect the frame from distortion due to warpage.
Better aluminum levels come with top reading windows, nonadjustable vials
and protective end plates.
torpedo level, approximately 9" long, is used for work in close quarters.
It is most popular among mechanics, hobbyists and householders.
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