Mitutoyo 111-166 Spline Micrometer 1 Inch 38mm Throat Depth

Product Description

The MITUTOYO 111-166 is a mechanical spline micrometer designed for precise internal measurement of spline and keyway features. It measures up to 1 inch with an accuracy of 0.00015 inches and a graduation of 0.0001 inches, making it suitable for close-tolerance inspection work. The 1/4-inch spindle diameter and 18mm head diameter allow access into confined geometries. The ratchet stop thimble ensures consistent measuring force, reducing operator-to-operator variation. The satin chrome finish resists corrosion and reduces glare under shop lighting. Machinists, toolmakers, and quality control technicians use this instrument for production and inspection environments.

The 111-166 is suited for measuring spline bores, keyways, and other internal features where a standard inside micrometer cannot reach. The 38mm throat depth provides clearance for most typical spline shaft and gear hub applications. It is used in precision machining shops, aerospace component inspection, and general metrology workflows. The instrument ships with a plastic storage case for protection during transport and storage. It carries TUV certification, confirming it meets recognized accuracy and quality standards for measuring instruments.

Key Features

• Measures up to 1 inch with 0.0001-inch graduation for high-resolution readings
• Accuracy rated to 0.00015 inches for close-tolerance inspection
• 38mm throat depth allows access to deep spline and keyway bores
• 1/4-inch spindle diameter with 18mm head fits confined internal features
• Ratchet stop thimble provides repeatable, consistent measuring pressure
• Satin chrome finish for corrosion resistance and reduced glare
• TUV certified; includes plastic protective case

Compatibility

Designed as a direct-use spline micrometer for internal measurement of spline bores, keyways, and similar features requiring a small-diameter spindle head. Compatible with standard metrology workflows in precision machining and quality inspection environments.

Installation Notes

This instrument is handled and calibrated by machinists, toolmakers, or quality control technicians. Before use, zero the micrometer per the manufacturer calibration procedure and verify against a known standard. Do not force the spindle into a bore; use the ratchet stop to apply controlled, consistent pressure. Store in the included plastic case when not in use to protect the spindle and measuring faces from damage.