INSIZE telescopic inside micrometer set 8–150 mm, 6 pieces (model 4206-1)

The INSIZE telescopic inside micrometer set 8–150 mm, 6 pieces is a precision measuring tool designed for internal diameter and bore measurement in workshops and quality control environments. The set includes six interchangeable telescopic rods that combine to cover a continuous measuring range from 8 mm up to 150 mm. Each telescopic section extends stepwise and locks to provide a stable reference length for comparison with a micrometer head or comparator, enabling accurate measurement of holes, cylinders and recessed features where direct access is limited.

Advantages

The telescopic inside micrometer set offers modular measurement coverage with six rods to minimise the need for multiple separate instruments. Its telescopic sections provide repeatable extension and secure locking for stable measurements in deep bores and narrow cavities. The design reduces measurement error from angular misalignment by allowing gradual insertion and extension inside the workpiece, and the set is suitable for use with standard micrometer heads or comparators to achieve fine resolution and traceable readings.

Suitable for

• Measuring internal diameters of holes and cylinders in metalworking
• Inspection of bores and recesses in assembled parts and housings
• Quality control checks in production and maintenance shops
• Use with micrometer heads or gauge comparators for high-precision tasks

Key specifications

• Measurement range: 8–150 mm using combined telescopic rods
• Number of rods: 6 interchangeable telescopic sections
• Application: internal diameter and bore measurement in restricted access areas
• Compatibility: intended for use with external micrometer heads or comparator measuring devices
• Typical use environment: workshop metrology and quality control

How to use

Select the appropriate combination of telescopic rods to reach the approximate bore depth or diameter, then assemble and insert the telescopic stack into the hole or recess. Gradually extend the telescopic sections until the measuring face contacts the internal surface, ensuring the instrument is aligned coaxially with the bore. Lock the sections to fix the length, then transfer the dimension to a micrometer head or comparator gauge to read the final internal diameter. Clean contact surfaces before measurement and avoid applying excessive lateral force that could tilt the stack.

Usage recommendations

For best accuracy, perform measurements at stable ambient temperature, verify micrometer heads against calibration standards before use, and handle telescopic rods by the non-contact areas to avoid contaminating measuring faces. Store the set in its protective case when not in use to prevent damage and maintain calibration.