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More Information
Mfg SKU #303-3441
Bore Gage CategoryElectronic
BrandShars Tool
Minimum Measuring Range4.921", 125mm
Maximum Measuring Range5.905", 150mm
Setting Ring4.9213
Contact Points3


This versatile and self-centering 3 point internal micrometer are designed for accurate and repeatable measurement of internal diameter.  Measurement can be taken closed to the bottom of a blind hole or in a deep hole with extensino rod.  3 point anvils evenly spaced at 120 degree apart, contact the internal wall surface and find the true alignment with the bore axis for accurate ID measurement.


  • Calibration procedure: 1) Before placing the micrometer into the supplied ring gage, press and hold the on/off/set key to go into the preset mode and use either hold or in/mm/0 key to adjust value as the ring gage diameter and toggle the decimal place by pressing the on/off/set key; Once the ring gage diameter is set in the Preset mode, press and hold the on/off/set key to exit the Preset mode. 2) Place the internal micrometer into the supplied ring gage and ensure repeatable contact with the interal bore surface 3) While the micrometer still is in the ring gage, press & hold the in/mm/0 key to set the micrometer to its preset value
  • 3 Point contact with tungsten carbide measuring anvil on range above .5"


  • Ratchet stop would apply constant measuring force to capture repeatable bore measurement

  • Inch/mm/0 function key: short press to toggle between inch or metric; press & hold key would toggle between relative or absolute measurement data
  • Hold function key: By pressing this key to hold the current bore measurement value regardless the movement of the micrometer thimble, allowing the user to retract the micrometer out of bore to faciliate easy reading. Deactivate this function by pressing the HOLD funciton key again.

  • Auto shut-off after 5 minutes and retain current measurement at power-on if not rotating the thimble
  • Included setting ring for easy calibration
  • 5.905" Long Extension rod included for measuring deep hole
  • SPC data port avaliable, connection cable (sku# 303-3597) sold separately
  • Contact Anvil Dimension

    L B C
    80mm 17mm 0.5mm

What’s Included

  • 1 pc of 3 point internal micrometer
  • 1 pc of setting ring
  • 1 pc of extension rod
  • 1 pc of adjusting wrench
  • 1 pc of 3V CR2032 battery
  • fitted in aluminum case