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Related to Dial caliper: Vernier calipers, Digital caliper


(US), caliper
1. an instrument for measuring internal or external dimensions, consisting of two steel legs hinged together
2. Med a splint consisting of two metal rods with straps attached, for supporting or exerting tension on the leg



a device that is lowered into a bore hole on a cable to determine the diameter of the hole. Mechanical and ultrasonic calipers are used.

The most commonly used mechanical caliper consists of three or four lever feelers (probes), which are pressed against the walls of the bore hole by springs, and a rheostat whose sliding contact is connected to the feelers by means of pushrods. A change in the diameter of the borehole produces a proportional change in the resistance of the rheostat. This resistance is measured on the surface and, as a result, a curve is produced showing the change in the diameter of the borehole from the face to the mouth of the hole. Recent models are equipped with a controlled lever device that can be opened and closed repeatedly on command from the surface.

An ultrasonic caliper is a hydrolocating device with two directional electroacoustic transducers located on opposite sides of the borehole instrument. Each transducer operates alternately as an ultrasonic oscillation emitter and detector. The time interval between the moments of the transducer’s emission and its reception of the ultrasonic pulse reflected from the wall of the borehole is measured on the surface. Since the interval is proportional to the distance from the device to the borehole wall, two longitudinal profiles of the borehole are produced, characterizing its diameter.

Since the cross section of a borehole is usually noncircular, instruments have been developed that permit measurement of the size and shape of the cross section.



(design engineering)
An instrument with two legs or jaws that can be adjusted for measuring linear dimensions, thickness, or diameter.


An instrument, resembling a pair of dividers, with adjustable legs for measuring the diameter or the thickness of bodies. Also see inside caliper and outside caliper.
References in periodicals archive ?
Among the many variations of dial indicators: long-range indicators for measuring table movement or slide travel, dial calipers for quick ID comparisons, pocket thickness gages for quick checks of materials, dial snap gages for ODs up to 12", dial bore gages for three-point contact go/no-go measurements, and back plungers where the mounting stem is on the back for mounting on holding fixtures.
All caliper measurements were taken using model Y3110337 digital calipers (Fischer Scientific, Pittsburgh, Pennsylvania, USA); therefore, times required to collect measurements are considered minimum estimates, as traditional non-digital dial calipers do not provide readable displays and their use would require additional time to determine measurements.
Because of that, explains Mike Weinstein, senior application engineer for Schaevitz Sensors Div., Measurement Specialties (Hampton, VA), LVDTs are replacing that handheld (read "manual") measurement devices, such as micrometers, dial indicators, and dial calipers, used by machinists all over.
A line of precision measuring instruments, which includes outside micrometers, dial calipers, dial indicators, test indicators, and height gages, is designed for the accurate reading of part features.
Also, an inside and outside digital or dial calipers, two test indicators and magnetic toolbases with adjustable stands, 0-1" micrometer, either a rotating head knee milling machine or the EVA quick change extractor cutting vise.
For simple modifications, a precision micrometer and dial calipers may be enough.
Three dial calipers (6", 8" and 12" range) are available that provide outside, inside, depth and step measurements in graduations of 0.001" and with accuracy to [+ or -]0.001" per 6".
I started with dial calipers and as soon as possible graduated to Electronic Digital Calipers.
RCBS was one of the first to offer dial calipers with their name on them and now they've added to that line with electronic LCD calipers and micrometers.