Spi 13-203-5 Steel Parallel 6x1-1/8x1/2 Inch Matched Pair

Product Description

The SPI 13-203-5 is a high-grade hardened steel parallel used to support and level workpieces during machining, grinding, and inspection operations. Measuring 6 inches long by 1-1/8 inches high by 1/2 inch thick, this parallel is precision ground on all four faces to a parallelism tolerance of 0.0003 inches and a squareness tolerance of 0.0005 inches. Hardened to 50 Rc for wear resistance, it maintains dimensional accuracy under repeated use. It is sold as a matched pair, making it suitable for applications requiring two identical reference surfaces.

This parallel is used in machine shops, tool rooms, and metrology environments. Typical applications include supporting workpieces in milling vises, setting up grinding fixtures, and establishing reference planes during layout and inspection. The four precision-ground faces provide multiple orientation options, allowing the parallel to be repositioned to different heights within a setup. Machinists, tool and die makers, and quality control technicians routinely use parallels of this type in both production and maintenance settings.

Key Features

• Four precision-ground faces for multiple setup orientations
• Parallelism tolerance of 0.0003 inches for repeatable accuracy
• Squareness tolerance of 0.0005 inches
• High-grade hardened steel at 50 Rc for long-term durability
• Sold as a matched pair for symmetric workholding setups

Compatibility

Designed as a standard precision parallel for use with milling vises, surface grinders, and inspection fixtures in general machining and toolroom applications.

Installation Notes

Parallels should be cleaned and inspected for burrs or nicks before each use to ensure accurate seating. Place the parallel on a clean, flat reference surface or directly in a vise jaw, then seat the workpiece firmly against it. Avoid using parallels as pry tools or striking surfaces, as this can damage the ground faces and compromise tolerance. Periodic inspection against a calibrated reference surface is recommended to verify continued accuracy.