Spi 13-213-4 Steel Precision Parallel Set 6in Matched Pair

Product Description

The SPI 13-213-4 is a matched pair of high-grade hardened steel precision parallels used for fixturing, setup, and inspection work in machining and toolroom environments. Each parallel measures 6 inches long by 1-1/8 inches high by 1/4 inches thick and is precision ground on all four faces to a parallelism tolerance of 0.0003 inches and a squareness tolerance of 0.0005 inches. Hardness is rated at 50 Rc, giving these parallels the wear resistance needed for repeated use in accurate workholding setups. Machinists, toolmakers, and metrology technicians rely on this grade of parallel for reliable, repeatable positioning.

These parallels are suited for use in manual and CNC machine shops, toolrooms, and quality control environments. Common applications include supporting workpieces during milling, grinding, and inspection operations where a flat, accurate reference surface is required. The matched-pair configuration ensures both pieces hold the same tolerances, making them interchangeable within a setup. They are appropriate for both production and jobbing environments where tight setup tolerances are expected.

Key Features

• Matched pair — both parallels ground to the same tolerance for interchangeable use
• Four-face precision ground construction — 0.0003 inches parallelism tolerance
• Squareness tolerance of 0.0005 inches for accurate workpiece registration
• High-grade hardened tool steel at 50 Rc for long service life
• 6 inches long by 1-1/8 inches high by 1/4 inches thick — a common size for vise and fixture setups

Compatibility

Designed as a general-purpose precision parallel for use with standard machinist vises, surface plates, and fixturing systems where 6-inch-length parallels are required.

Installation Notes

Precision parallels should be handled with clean, dry hands or lint-free gloves to prevent corrosion from skin oils. Inspect contact surfaces for burrs or nicks before use and stone lightly if needed to preserve tolerance integrity. Store parallels together in their matched pair to maintain traceability. These are setup and workholding tools, not structural components — do not use them as pry bars or striking surfaces.