INSIZE digital 3-jaw inside micrometer 16–20 mm IP65 model 3127-20

INSIZE digital 3-jaw inside micrometer 16–20 mm IP65 model 3127-20 is a precision measuring instrument designed to determine internal diameters with a three-point contact system and a digital readout. The 16–20 mm measuring range covers small bores and holes commonly found in mechanical parts, assemblies and quality-control inspections. IP65 protection ensures resistance to dust and low‑pressure water jets, making the tool suitable for workshop environments where contamination or coolant may be present.

Advantages

The three-jaw contact design provides stable centring and repeatable measurements across cylindrical bores, reducing operator error compared with two-point methods. The digital display gives fast, easy-to-read measurements and can improve throughput during inspection and assembly tasks. Built with materials and an IP65 sealing grade, the micrometer tolerates common workshop contaminants and maintains measurement reliability in harsher conditions.

Suitable for (tasks / use cases)

• Bore gauging on small-diameter holes and cylinders
• Incoming inspection and quality control of machined parts
• Dimensional checks during assembly and fit verification
• Routine shop-floor measurement where digital readout and protection are needed

When it may not be suitable

This micrometer is intended for internal diameters in the 16–20 mm range; it is not suitable for measuring external features, deep bores beyond its reach, or diameters outside of its specified range. For ultra-high-precision laboratory metrology where environmental control and traceable calibration to specific standards are required, a calibrated reference instrument or gauge block system may be more appropriate.

Key specifications

• Measuring range: 16–20 mm
• Contact system: three-jaw (three-point) internal contact
• Display: digital readout for direct measurement reading
• Ingress protection: IP65 (dust-tight and protected against low-pressure water jets)
• Typical application: internal diameter measurement, bore gauging, quality control

How to use

Center the micrometer inside the bore so the three contact jaws make uniform contact with the internal surface. Rotate or actuate the mechanism according to the manufacturer’s instructions until the jaws seat evenly, then read the measurement from the digital display. For best results, ensure the instrument and workpiece are clean and at stable ambient temperature; take multiple readings at different orientations if required to detect out-of-roundness and to confirm repeatability.

What to consider before purchase

• Required measuring range: ensure 16–20 mm covers the parts you need to measure
• Environmental conditions: IP65 provides dust and light water protection but is not for submersion
• Accuracy and calibration needs: verify the instrument’s stated accuracy and plan for calibration if traceability is required
• Access and bore depth: confirm the jaw length and instrument geometry suit the bore depth and accessibility

Usage recommendations

Clean contact surfaces and avoid shock or side loads on the jaws; store the micrometer in a protective case when not in use and follow the manufacturer’s calibration schedule to preserve measurement accuracy and prolong service life.