Spi 10-747-4 Micrometer Extension Hole-mike Series

Product Description

The SPI 10-747-4 is a micrometer extension accessory designed for use with SPI Hole-Mike Series inside micrometers. It extends the measurement range of compatible Hole-Mike instruments, allowing technicians to reach deeper bore measurements without switching tools. The extension provides a minimum extension of 1.6 inches and a maximum extension of 4.0 inches, supporting a maximum measurement reach of 6.0 inches overall. Weighing 1.8 pounds, it is a solid, practical addition to any precision measurement toolkit used in machining, inspection, or maintenance environments. Machinists, tool room technicians, and quality control professionals are the primary users of this accessory.

This extension is intended for use in applications where bore depth or inside diameter measurements exceed the standard reach of the base Hole-Mike instrument. Typical use scenarios include measuring deep bores in engine blocks, hydraulic housings, pump bodies, and similar machined components. It is suited for both shop floor and inspection room environments where inside micrometer measurements need to be extended without sacrificing accuracy or repeatability. It is compatible specifically with the SPI Hole-Mike Series micrometer line as specified by the manufacturer.

Key Features

• Minimum extension of 1.6 inches for close-range bore reach
• Maximum extension of 4.0 inches to access deeper bores
• Supports overall maximum measurement of 6.0 inches when paired with a compatible Hole-Mike instrument
• Designed as a direct accessory for SPI Hole-Mike Series micrometers
• Compact and lightweight at 1.8 pounds for easy handling at the bench or on the floor

Compatibility

Designed for use with SPI Hole-Mike Series inside micrometers as specified by the manufacturer.

Installation Notes

This extension is installed by machinists or metrology technicians familiar with inside micrometer systems. Before attaching the extension, ensure the base micrometer is clean and free of debris at the connection point to maintain measurement accuracy. Follow the instrument manufacturer instructions for proper thread engagement and seating. Do not force the extension onto the micrometer spindle, as this may damage precision threads and affect calibration.