Spi 13-239-9 Steel Parallel Set 8 Piece 6 Inch

Product Description

The SPI 13-239-9 is an 8-piece hardened steel parallel set designed for precision machining and metrology work. Each parallel is 6 inches long and ground on all four sides to close tolerances, delivering a parallelism accuracy of 0.0002 inches. With a hardness rating of 52 to 58 RC, these parallels resist wear and maintain dimensional stability under repeated use. The set includes four matched pairs spanning a height range of 0.5 inches to 1 inch and a thickness range of 0.125 inches to 0.375 inches. Machinists, tool-and-die makers, and quality control technicians rely on sets like this for vise setup, part inspection, and surface plate work.

This parallel set is suited for use in machine shops, tool rooms, and inspection departments handling precision work on milling machines, surface grinders, and inspection fixtures. The four pairs cover a practical range of thickness-to-height combinations, making this set useful for a variety of workholding and gauging setups. Each pair is matched and consistent, allowing accurate part positioning and repeatable results across multiple setups. The included case keeps the parallels protected and organized between uses.

Key Features

• Ground on all four sides to a parallelism tolerance of 0.0002 inches
• Hardened steel construction at 52 to 58 RC for long-term dimensional stability
• 6 inches long with four distinct thickness-height pair combinations
• Sold as 4 matched pairs (8 pieces total)
• Includes a protective storage case
• Height range 0.5 inches to 1 inch; thickness range 0.125 inches to 0.375 inches

Compatibility

Designed as a general-purpose precision parallel set suitable for use with standard milling machine vises, surface plates, and inspection fixtures requiring workpiece support within the stated height and thickness ranges.

Installation Notes

Parallels are typically set up by machinists and tool-and-die makers as workholding aids during milling, grinding, and inspection operations. Before placing parallels in a vise or fixture, clean all contact surfaces to remove chips, coolant, and debris that can introduce error. Handle parallels carefully to avoid nicks or burrs on the ground surfaces, which will compromise accuracy. Store in the provided case when not in use to protect the ground surfaces.