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Related to Digital calipers: Dial calipers


(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 ?
introduces a new line of digital calipers and micrometers that assure precise and reliable measurements under difficult conditions.
Information for molding machines is obtained through the IMAC data acquisition unit, which performs three functions: it continually monitors up to 32 production/process parameters and reports any deviations that exceed established limits; it provides an interface which allows downtime and defect codes to be entered, production and engineering data to be reviewed, and the addition of stacklights for additional status information on the plant floor; and it furnishes an interface to quality control instruments such as digital scales, digital calipers and digital micrometers.
Digital calipers and micrometers are being used extensively for their ease of use and accurate measurements, notes the analyst of this research service.
Tenders are invited for Vernier Digital Calipers Model 1320, Capacity - 200Mm Resolution - 001Mm Repeatability - 10 M Bias Error - 30 M A - 290Mm, B - 50Mm C - 14Mm, D - 20Mm Make-Baker/Mitutoyo Only