Internal Micrometer INSIZE 3220-75, range 50–75 mm, flat-end anvils

INSIZE internal micrometer 3220-75 is a precision measuring instrument with a 50–75 mm measuring range and flat-end anvils. It is designed to measure internal diameters of bores, sleeves and cylindrical parts where stable, repeatable contact is required. The flat-end contact points ensure consistent seating against the measured surface, making the tool suitable for workshop inspections and quality-control checks that demand accurate internal sizing.

Advantages

The flat-end anvils provide stable, full-surface contact for repeatable measurements and reduced measurement variation. A compact, purpose-built frame and finely graduated spindle allow for controlled approach and precise reading within the 50–75 mm range. The instrument is engineered for practical use in production and inspection environments, offering reliable performance on cylindrical and bore geometries without requiring additional adapters.

Suitable for

• Measuring internal diameters of bores and sleeves within 50–75 mm
• Quality control and inspection of cylindrical parts
• Workshop fitting and assembly checks where internal sizing is critical

Key specifications

• Measuring range: 50–75 mm
• Contact type: flat-end anvils (plunger contact)
• Intended measurement target: internal diameters of bores, sleeves and cylindrical parts
• Application environment: workshop, inspection and quality control

How to use

Insert the micrometer into the bore or sleeve and rotate the spindle until the flat-end anvils make stable contact with the internal surface. Use the fine adjustment to achieve a snug, non-deforming contact and read the measurement according to the micrometer's scale or digital/analog indication if equipped. For best results, take multiple readings at different orientations and average them when assessing roundness or concentricity. Keep the instrument clean and handle the spindle carefully to maintain calibration and accuracy.

Usage recommendations

Before measurement, ensure mating surfaces are free of chips, burrs and coolant. Allow the micrometer and the workpiece to reach the same ambient temperature to avoid thermal measurement errors. Store the micrometer in its protective case when not in use and have it calibrated periodically to preserve measurement accuracy.