Spi 13-186-2 Sine Bar 6 Inch Hardened Steel

Product Description

The SPI 13-186-2 is a hardened steel sine bar used for precision angle setup and measurement in machining, inspection, and toolroom applications. The bar measures 6 inches long by 1 inch wide, with rolls spaced 5 inches center to center. Center-to-center roll accuracy is rated at 0.0002 inches, and parallelism is held to 0.0001 inches. A back plate is included. These tight tolerances make this tool suitable for setting compound angles on surface plates, checking tapers, and qualifying fixtures to a known angular reference. Machinists, tool and die makers, and quality technicians rely on sine bars where angular accuracy is critical.

The SPI 13-186-2 is suited for toolroom and quality lab use in precision manufacturing environments. Typical applications include angle layout on a surface plate with gauge blocks, inspection of tapered features, and angular setup of workholding fixtures on mills and grinders. The included back plate adds rigidity and expands setup options for horizontal and vertical work. This bar is appropriate for both job shop and production inspection workflows where repeatable, traceable angular measurement is required.

Key Features

• Hardened steel construction for wear resistance and dimensional stability
• Center-to-center roll accuracy of 0.0002 inches for reliable angular calculation
• Parallelism held to 0.0001 inches across the working surface
• 5 inch roll spacing simplifies sine calculations using standard gauge block stacks
• Back plate included for added rigidity and versatile mounting
• Compact 6 inch x 1 inch footprint fits standard surface plate workflows

Compatibility

Designed for use on standard surface plates with conventional gauge block sets in toolroom, inspection, and precision machining setups.

Installation Notes

Sine bars are used by metrology technicians, machinists, and tool and die makers and require no permanent installation. Clean the surface plate and bar mating surfaces before use to prevent contamination from affecting accuracy. Handle with care to avoid dropping, which can alter roll geometry and compromise calibration. Periodic recalibration against a known standard is recommended to confirm ongoing accuracy.