Hardened Spherical Telescopic Bore Gauge

A 4-piece telescopic bore gauge set designed for precise internal diameter measurement in UK workshops and light industrial settings. Each gauge is built to measure bores from 3 mm up to 14 mm using the transfer method with an outside micrometer. Overall length is 10.5 cm, with a compact 1 cm × 1 cm profile for access to tight spaces. Made from durable metal with fully hardened spherical measuring tips and a satin-finished adjustment shaft for consistent extension control. The spherical geometry ensures automatic self-centring in round holes, improving repeatability. All four sizes are supplied together in a custom-fitted storage case for protection and quick identification.