Interior gauge

Interior Gauge. It is a gauge to verify internal diameters, characterized by the fact that it consists of an intermediate handle, at whose ends two “pass” and “do not pass” gauges are mounted, freely rotatable in relation to the handle.


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  • 1 Description
  • 2 parts
  • 3 Operation
  • 4 types
  • 5 Recommendations
  • 6 Sources


The interior gauge is one of the measuring tools mostly used in mechanical work, and for the measurement of precision work, they are used to make external measurements, internal measurements and depths, the gauge has a graduated ruler called nonius through the which can be seen the value that is being measured, currently, the digital calipers are the most used, the internal calipers are used to make measurements of grooves or internal diameters, as its name indicates.


The gauge has several elements for measuring objects , which are described here:

  • The ears are used to measure the interior faces of the pieces.
  • The jaws are used to measure the volume of the same inner faces of the pieces.
  • The rod that comes out from the bottom of the gauge is used to measure the depth of objects.
  • The locking and unlocking nut allows sliding the gauge and fixing it during the measurement of the piece.
  • The digital gauges also have a button for resetting (it can be zeroed in any position), and a button to go from millimeters to inches.


The ears are two elements that allow the internal diameters to be measured, the internal faces and, in general, internal geometric shapes, the locking and unlocking nut is used to adjust the nonius once the measurement has been achieved: by turning the nut clockwise, the nonius will be automatically locked and we will obtain a more accurate reading, turning the nut counter-clockwise unlocks the nonius, leaving it free again.


  • Turner gauge: this gauge is useful only for measuring exteriors and interiors, since it does not have the probe (rod used to measure depths).
  • Universal gauge with comparator: it has two pointed ears for interior measurements, and a jaw that also ends in a pointed position, thanks to its special probe, with this gauge we can also measure depths, we could say that this is a common gauge, with the peculiarity of having a dial gauge for a different measurement.
  • Blade type internal caliber: its jaws are knife- type and long, this allows us to take interior dimensions in depth, the length of the jaws are around 50 to 90 mm, depending on the model.
  • Inner gauge with knife contacts: Due to the special shape, it is used to measure grooves.


To measure inside: for inside diameters, read the scale while the indicated value is at its maximum; For the width of a slot read the minimum. Select the calibrator that best suits your measurement needs. Do not apply too much force to the gauge while measuring. Take care not to damage the indoor measuring tips. Before use, remove any dirt ( dust , lint, etc.) from the gauge . During the measurement, the cursor must not be loose, correct and adjust the fixing and precision screws . In the case of using digital gauges, the batteries must be in good condition, since otherwise they will not indicate real measurements.


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