Description

The MITUTOYO 154-108 is a small hole gage used to measure the internal diameter of small bores, holes, and grooves. It features a half ball contact style that expands to contact the bore wall, allowing the technician to transfer the measurement to an outside micrometer for a precise reading. The measurement range covers 0.4 to 0.5 inches, making it suited for close-tolerance work in machining, engine rebuilding, and precision fabrication. Overall length is 4.25 inches. This tool is a standard instrument in any machine shop, engine shop, or precision maintenance environment.

The 154-108 is intended for use wherever accurate internal bore measurement is required in the 0.4 to 0.5 inch range. Typical applications include checking cylinder bores, valve guides, bushing bores, and bearing seats during machining or inspection operations. It is used by machinists, engine builders, toolroom technicians, and precision maintenance professionals in both production and service settings.

Key Features

Measurement range: 0.4 to 0.5 inches for small internal bore gauging
Half ball contact style for positive contact in blind or through bores
Overall length of 4.25 inches for comfortable single-hand use
Transfer-type design works in conjunction with an outside micrometer for final reading
Compact size suited for tight-clearance bore locations

Compatibility

Designed as a standard small hole gage for use with any outside micrometer capable of reading in the 0.4 to 0.5 inch range.

Installation Notes

Small hole gages require no installation in the traditional sense but should be handled by qualified inspection or machining personnel. Before use, ensure the gage and the bore being measured are at the same ambient temperature to avoid thermal expansion errors. Expand the gage contact gently within the bore to avoid damaging the bore surface or the gage tip. After transferring the measurement, read the outside micrometer on a stable surface and zero the instrument before use according to standard metrology practice.