Spi 12-404-0 Inside Dial Caliper Gage 1.5 to 2.5 in

Product Description

The SPI 12-404-0 is an inside dial caliper gage designed to measure internal dimensions from 1.5 inches to 2.5 inches with a graduation of 0.001 inches and an accuracy of 0.0015 inches. The gage features ball contact points and 3.25-inch legs, making it well suited for bore, groove, and slot measurement tasks where consistent point contact is critical. The body is constructed from a combination of aluminum alloy, copper alloy, and steel, balancing durability with manageable weight. Machinists, tool and die technicians, and quality-control inspectors are the primary users of this instrument in shop and inspection environments.

This inside dial caliper gage is used in precision measurement applications where inside diameters, slot widths, or groove dimensions fall within the 1.5-inch to 2.5-inch range. The 3.25-inch leg length provides reach into deeper bores and recesses. Ball contact points reduce the effect of surface irregularities on readings, which is especially useful when measuring cast, bored, or honed surfaces. The instrument is appropriate for both production floor spot-checking and dedicated inspection station use.

Key Features

• Measurement range of 1.5 inches to 2.5 inches for inside dimensions
• 0.001-inch graduation for fine-resolution dial readings
• 0.0015-inch accuracy rating for reliable inspection-grade results
• Ball contact points with a 0.060-inch tip diameter minimize surface contact error
• 3.25-inch leg length allows measurement in deeper bores and recesses
• Multi-material construction: aluminum alloy, copper alloy, and steel components

Compatibility

Designed as a general-purpose inside dial caliper gage for use in any shop or inspection environment requiring internal measurement within the 1.5-inch to 2.5-inch range. No specific compatible models or replacement part numbers were identified in the available product data.

Installation Notes

This instrument is handled and used by machinists, metrologists, and quality technicians rather than installed in a system. Before use, zero the dial indicator at the reference setting and verify the ball contact points are clean and undamaged. Store the gage in its case away from heat sources, coolants, and abrasive contaminants to preserve calibration. Periodic calibration against a certified ring gage or bore standard is recommended to maintain accuracy.