Spi 21-907-1 Mechanical Hole Micrometer 1.6-2 in

Product Description

The SPI 21-907-1 is a mechanical hole micrometer designed for precise internal bore measurement in the range of 1.6000 to 2.0000 inches. It features a ratchet stop thimble for consistent measuring pressure and three self-centering contact points that automatically align to the bore centerline, reducing operator error. Graduated at 0.0002 inches with an accuracy of 0.0002 inches, this tool is suited for quality control, incoming inspection, and machining verification tasks. The chrome finish and carbide measuring surfaces provide durability in shop environments. Calibration traceability is certified to NIST standards, making it appropriate for work requiring documented measurement traceability.

The 21-907-1 is used in machine shops, manufacturing facilities, and precision inspection environments where accurate internal diameter measurement is required. It is appropriate for measuring bored holes, cylinders, and other internal features in the 1.6000 to 2.0000 inch range. The included setting ring (1.6000 inch diameter) allows for on-site zeroing and verification. One extension rod is included, with a maximum extension rod length of 6.0000 inches and a gage depth of 3.8200 inches, allowing measurement in deeper bores. Machinists, quality technicians, and metrologists are the primary users of this instrument.

Key Features

• Measurement range: 1.6000 to 2.0000 inches with 0.0002 inch graduation and 0.0002 inch accuracy
• Three self-centering contact points for repeatable, centered bore alignment
• Ratchet stop thimble ensures consistent, controlled measuring pressure
• Carbide measuring surfaces resist wear for long-term accuracy retention
• NIST-traceable calibration certification included
• Includes one setting ring (1.6000 inch diameter) and one extension rod

Compatibility

Designed for use as a mechanical internal bore micrometer in precision measurement applications requiring a 1.6000 to 2.0000 inch internal measuring range.

Installation Notes

This instrument is a handheld precision measuring tool and does not require installation in the traditional sense. Before use, zero and verify the micrometer against the included setting ring on a stable, vibration-free surface. Handle carbide contact points with care to avoid damage from dropping or impact. Store in the provided case when not in use to protect the calibrated surfaces and maintain measurement integrity.