Mitutoyo 331-351-30 Electronic Spline Micrometer 1 in

Product Description

The MITUTOYO 331-351-30 is an electronic spline micrometer designed for precision outside-diameter measurement of splined shafts, keyways, and other narrow or recessed workpiece features. It delivers a measuring range of 1 inch with an accuracy of 0.0001 inch and a resolution of 0.00005 inch (0.001 mm), making it suitable for high-tolerance machining and inspection work. The slim spline head allows access into tight geometry where a conventional outside micrometer cannot reach. A ratchet stop thimble ensures repeatable, consistent measuring force on every reading. The satin chrome finish reduces glare and resists corrosion in shop environments.

This micrometer is used in precision machine shops, toolrooms, quality control labs, and manufacturing environments where splined components require accurate dimensional verification. The 0.25 inch spindle diameter and narrow head geometry are intended for measuring spline root diameters, gear features, and similar tight-clearance surfaces. Data output capability allows integration with statistical process control (SPC) systems and external data loggers, supporting ISO-compliant inspection workflows. It ships complete with a plastic storage case. Installation and use are performed by machinists, metrologists, quality technicians, and tool-and-die professionals.

Key Features

• Electronic readout with 0.00005 inch (0.001 mm) resolution for high-precision measurement
• Accuracy rated to 0.0001 inch, meeting tight-tolerance inspection requirements
• 1.2598 inch throat depth provides reach into recessed or splined geometry
• Ratchet stop thimble delivers consistent, repeatable spindle pressure
• Data output port supports SPC and external recording systems
• Satin chrome finish minimizes glare and improves durability in shop use
• TUV certified; includes plastic carrying case

Compatibility

Designed as a precision measurement instrument for splined shafts and narrow-profile workpieces requiring outside-diameter measurement within a 1 inch range. Compatible with standard SPC data collection systems via the built-in data output port.

Installation Notes

This instrument requires no installation in the traditional trade sense but should be handled and stored by qualified metrology or quality personnel. Before use, verify calibration against a known standard and allow the micrometer to thermally stabilize to shop ambient temperature. Clean the spindle faces and anvil with a lint-free cloth before measurement. Do not force the spindle or use the thimble barrel to apply excess pressure beyond what the ratchet stop allows.