Spi 20-633-4 Test Indicator Ball Contact Point Ruby

Product Description

The SPI 20-633-4 is a ruby ball contact point designed for use with test indicators in precision measurement applications. The contact point features a 2.00 millimeter (0.078 inch) ruby ball tip, which provides hard, wear-resistant contact against workpiece surfaces during runout, concentricity, and surface deflection measurements. The total contact point length is 0.671 inches. Ruby tip material is preferred in metrology work because it resists flat-spotting and maintains dimensional accuracy over repeated use. This part is installed by machinists, quality control technicians, and tool and die professionals who rely on dial test indicators for close-tolerance inspection work.

This contact point is intended for use with Teclock test indicators. It is a replacement or spare tip for bench inspection setups, CMM staging, surface plate work, and machine tool calibration checks in both shop floor and laboratory environments. The 0.078 inch ball diameter makes it suited for applications where a small, precise contact area is required to capture fine surface variation without bridging features.

Key Features

• Ruby ball tip material provides high hardness and wear resistance for extended service life
• Ball diameter of 2.00 millimeters (0.078 inches) for precise, localized contact
• Contact point length of 0.671 inches suits standard Teclock indicator stem geometry
• Replacement-grade component for maintaining indicator accuracy over time
• Lightweight at 0.1 pounds, adding negligible mass to indicator stylus assembly

Compatibility

Designed for use with Teclock test indicators as stated by the manufacturer. Verify thread type and stem diameter against your specific indicator model before ordering.

Installation Notes

Contact point replacement on test indicators is typically performed by metrology technicians or experienced machinists. Before replacing the contact point, remove the indicator from any active measuring fixture to avoid accidental deflection or damage to the indicator mechanism. Use the appropriate wrench or spanner for the contact point thread — do not overtighten, as excessive torque can damage the indicator spindle threads. After installation, zero the indicator and verify tip runout against a reference surface before returning the instrument to service.