Spi 77-643-5 Square Straight Edge 36 in Spring Steel

Product Description

The SPI 77-643-5 is a square straight edge measuring tool used to verify flatness, check surface alignment, and establish reference lines in precision machining, fabrication, and metrology applications. Made from spring steel, it measures 36 inches in overall length, 2-13/32 inches wide, and 3/8 inches thick. Edge flatness is held to 0.0008 inches (15 micrometers), and parallelism is held to 0.0016 inches (30 micrometers). These tolerances make it suitable for inspection and layout work where accurate surface referencing is required. Machinists, toolmakers, and quality control technicians are the primary users.

This straight edge is intended for use in machine shops, tool rooms, and inspection departments. It serves as a reference tool for checking the flatness of machined surfaces, aligning workpieces on surface plates, and scribing layout lines. The 36-inch length makes it appropriate for medium to large workpiece inspection. Spring steel construction provides a combination of rigidity and resistance to permanent deformation under normal shop use conditions.

Key Features

• Edge flatness of 0.0008 inches (15 micrometers) for precise surface verification
• Parallelism tolerance of 0.0016 inches (30 micrometers)
• Spring steel construction resists deformation and corrosion in shop environments
• 36-inch length suitable for medium to large surface inspection tasks
• Square edge type provides a consistent reference profile along the full length

Compatibility

Designed as a general-purpose precision straight edge for use in machining, fabrication, and inspection applications requiring a 36-inch reference tool with spring steel construction.

Installation Notes

Handle with clean, dry hands or lint-free gloves to prevent oils from the skin from causing corrosion on the spring steel surface. Store flat or supported along its full length to prevent warping over time. Clean and lightly oil the surface before storage if the tool will not be used for extended periods. No power source or mechanical installation is required for this tool.