Bore gauge

Transfer Gauges
– Telescopic gauges:
– Used to measure bore size by transferring internal dimension to a remote measuring tool
– Require operator to develop correct feel for repeatable results
– Locked by twisting knurled end of handles to exert friction on telescopic portions
– Inserted at slight angle to bore and gently locked to size slightly larger than bore
– Rocking handle side-to-side aligns gauge with bore axis and brings it to exact bore diameter
– Small-hole gauges:
– Initially set smaller than bore to be measured
– Adjusted by rotating knurled knob until light pressure is felt when gauge is slightly moved in bore
– Available in full-ball and half-ball styles
– Full-ball gauges are easier to set and maintain accurate representation of bore
– Half-ball gauges require lighter touch and may introduce measurement errors
– Beam gauges for larger diameters:
– Designed to measure internal and external diameters
– Lightweight with low coefficient of thermal expansion, high modulus, and stiffness
– Stem with ball at both ends, length range depends on width of part
– Slide one end of beam on diameter and watch dial indicator to measure bore diameter
– Repeat procedure in 3 different places and average values for accurate measurement
– Inside Micrometer:
– Measures bore directly
– Three symmetrical anvils protrude from gauge body
– Knob rotates to move anvils in or out for measurements
– Mean diameter of three anvils is given measurement, usually accurate to 0.001mm
– Dial Bore Gauge:
– Comparative instrument with digital or analog readout
– Must be set to nominal value of bore and measures variation and direction from nominal
– Can be set using outside micrometer, ring gauge, or designated bore gauge setting equipment
– Contact needle housed inside gauge head transfers data to dial or readout
– Head inserted into bore and measurements obtained by tilting gauge back and forth

Electronic and Wireless Bore Gauges
– This section is empty. (Can be expanded upon)

See also
– Pin gauge

References
– De Silva, G. M. S. (2002), Basic metrology for ISO 9000 certification, Butterworth-Heinemann, p.28, ISBN978-0-7506-5165-3
– Schuetz, George (September 2017). Adjustable Bore Gages. Modern Machine Shop. 90 (4): 58, 60. ProQuest1936137174. Source:  https://en.wikipedia.org/wiki/Bore_gauge