Spi 21-130-0 Ruby Ball Contact Point Tesa Test Indicators

Product Description

The SPI 21-130-0 is a ruby ball contact point designed for use with dial-type test indicators in precision measurement applications. The ruby ball tip measures 0.078 inches in diameter and the full contact point length is 1.437 inches. Ruby is the preferred tip material for high-cycle gauging work because it resists wear and maintains dimensional accuracy far longer than carbide or steel alternatives. This contact point is installed by metrology technicians, QC inspectors, and machinists performing runout, concentricity, or surface variation checks.

This contact point is suited for inspection setups on machine tools, surface plates, and fixturing environments where a low-mass, accurate tip is required. Its ball-style geometry allows contact on curved and flat surfaces alike, making it a practical choice for a wide range of workpiece geometries in both production and tool-room settings.

Key Features

• Ruby ball tip for extended wear life in high-cycle inspection applications
• Ball diameter of 0.078 inches (2.00 mm) for precise point contact
• Contact point length of 1.437 inches for reach in standard indicator setups
• Designed for use with Tesa test indicators
• Lightweight construction at 0.1 pounds to minimize indicator stylus deflection

Compatibility

Designed for use with Tesa test indicators as specified by the manufacturer.

Installation Notes

Contact points are installed and removed by hand or with a small wrench depending on the thread style of the indicator stem — power down any automated gauging station before servicing. Avoid over-tightening the contact point, as this can damage the indicator spindle thread. Inspect the ruby ball for chips or flat spots before each use to ensure measurement integrity.