Spi 10-712-8 Mechanical Hole Micrometer 0.425 Inch

Product Description

The SPI 10-712-8 is a mechanical hole micrometer designed for precise internal bore measurement. It covers a measurement range up to 0.425 inches with a graduation of 0.0001 inches and an accuracy of 0.0001 inches, making it suitable for tight-tolerance inspection work. The ratchet stop thimble provides consistent measuring pressure across readings, reducing operator-to-operator variation. Measuring faces are solid carbide for long service life under repeated use. This tool is used by machinists, quality control technicians, and precision metrology professionals in machine shops and manufacturing environments.

The 10-712-8 is intended for measuring small internal bores and holes where high accuracy is required. The three-point self-centering and self-aligning contact design ensures the instrument seats correctly within the bore without requiring manual adjustment. A gage depth of 2.0 inches allows reach into moderately deep features. The maximum extension rod length of 4.0 inches supports measurement of deeper bores when extension capability is used. This tool fits inspection workflows in production machining, toolroom work, and quality assurance applications.

Key Features

• Measurement range up to 0.425 inches with 0.0001-inch graduation
• Accuracy rated at 0.0001 inches for tight-tolerance inspection
• Ratchet stop thimble ensures repeatable, consistent measuring pressure
• Solid carbide measuring anvils for extended wear resistance
• Self-aligning and self-centering three-point contact design
• Gage depth of 2.0 inches; maximum extension rod length of 4.0 inches

Compatibility

Designed as a standalone mechanical hole micrometer for use in bore measurement applications requiring a range of up to 0.425 inches. No compatible extension rods or setting rings are included with this unit.

Installation Notes

This instrument is installed and operated by machinists or metrology technicians; no power source or wiring is required. Before use, verify calibration against a known standard appropriate to the measurement range. Keep the measuring faces clean and free of debris to maintain accuracy. Store in a protective case away from temperature extremes to prevent thermal expansion errors.