Manual Micrometers

An outside micrometer measures across a diameter or thickness using a calibrated screw thread, with a ratchet stop that applies the same measuring force every time — that consistency is what makes it repeatable between different people using the same tool. Every micrometer only covers a 25mm span of travel, which is why they're sold in sets rather than as a single tool: a 0-25mm micrometer can't measure a 40mm shaft.

We stock ranges from 0-25mm up through 150-300mm, in both single sizes and multi-piece sets (0-25/25-50/50-75/75-100mm being the most common shop set). Larger ranges — 100-125mm, 150-300mm — are typically bought individually rather than as part of a set, since fewer jobs need them. Imperial equivalents are stocked alongside the metric ranges.

All have hardened and ground measuring faces and a friction or ratchet thimble for consistent readings. For digital readout instead of a vernier scale, see Digital Micrometers. For checking runout and alignment rather than a fixed dimension, see Dial Test Indicators.