Spi 12-449-5 Setting Ring 1.8 Inches Id

Product Description

The SPI 12-449-5 is a precision setting ring used to calibrate and zero bore gauges, plug gauges, and internal measuring instruments. The ring has an inside diameter of 1.8 inches and an accuracy of 0.00006 inches, making it suitable for close-tolerance inspection work in toolrooms, machine shops, and quality-control environments. The outside diameter measures 3.35 inches and the ring is 0.79 inches thick, giving it a stable, hand-held form factor. Calibration technicians, machinists, and metrology professionals use setting rings as reference masters before taking critical internal measurements on production parts.

Setting rings of this class are used wherever bore gauges or air gauges must be set to a known reference diameter prior to measurement. Typical applications include incoming inspection, in-process quality checks on machined bores, and tool-room calibration routines. The 1.8-inch inside diameter suits a range of shaft fits and bore applications common in mechanical assemblies. This ring is supplied as a single unit and is intended for bench or floor-level metrology stations.

Key Features

• Inside diameter of 1.8 inches for direct reference setting of bore gauges
• Accuracy of 0.00006 inches supports high-precision calibration requirements
• Outside diameter of 3.35 inches and thickness of 0.79 inches provide a stable grip and handling profile
• Single-piece reference standard — no assembly required
• Suitable for toolroom, quality-lab, and production-floor calibration workflows

Compatibility

Designed as a reference standard for bore gauges, plug gauges, and internal measuring instruments requiring a 1.8-inch inside-diameter master ring. Confirm instrument range and diameter compatibility before use.

Installation Notes

Setting rings are handled and stored by metrology technicians and toolroom machinists, not installed in the field sense. Keep the ring clean and free of burrs, chips, and oil film before use, as surface contamination directly affects gauge zeroing accuracy. Store in a protective case away from temperature extremes to preserve dimensional stability. Do not use the ring as a mechanical fixture or drop it, as impact damage will affect calibration integrity.