Spi 13-218-3 Steel Parallel 6x3/4x3/8 in Precision Ground Pair

Product Description

The SPI 13-218-3 is a precision-ground steel parallel designed for use in machining, inspection, and toolroom applications. Measuring 6 inches long, 3/4 inches high, and 3/8 inches thick, this parallel features four precision-ground faces and a parallelism tolerance of 0.0003 inches. Manufactured from high-grade hardened tool steel at 50 Rc hardness, it delivers the dimensional stability required for accurate workpiece setup and part inspection. Sold as a matched pair, the 13-218-3 is suited for machinists, toolmakers, and metrology technicians who require consistent reference surfaces during milling, grinding, and layout operations.

This parallel is used in machine shop and toolroom environments where precise workpiece elevation and alignment are critical. Typical applications include supporting workpieces in vises during milling or grinding, establishing reference planes during inspection, and setting up parts for accurate layout work. The matched pair configuration ensures that both parallels share the same dimensional characteristics, making them suitable for side-by-side or stacked setups on surface plates and magnetic chucks.

Key Features

• Four precision-ground faces for versatile orientation and consistent reference surfaces
• Parallelism tolerance of 0.0003 inches for high-accuracy setups
• Squareness tolerance of 0.0005 inches
• High-grade hardened tool steel construction at 50 Rc for wear resistance and dimensional stability
• Sold as a matched pair for consistent paired setups
• Compact profile at 3/8 inches thick for low-clearance applications

Compatibility

Designed as a general-purpose precision parallel for use with standard machinist vises, surface plates, and magnetic chucks in toolroom and machine shop environments.

Installation Notes

Parallels should be handled carefully to avoid nicks or burrs that can affect accuracy. Clean all mating surfaces with a lint-free cloth before use. Store parallels in a protective case or on a padded surface to prevent contact damage. Inspect for burrs or wear periodically using a surface plate and indicator to verify parallelism remains within tolerance.