Spi 20-350-5 Cupped Ball Contact Point Dial Indicator

Product Description

The SPI 20-350-5 is a cupped ball contact point designed for use with dial indicators in precision measurement applications. Machined with a ruby contact tip and threaded to the AGD Group 1 standard 4-48 specification, this contact point delivers consistent, repeatable surface contact on workpieces where a standard flat or pointed tip would not seat correctly. The cupped ball geometry captures round or spherical features and provides stable registration during measurement. At 0.75 inches in length and 4 mm in ball diameter, it is a direct-fit replacement or accessory upgrade for most AGD-compatible dial indicators. Metrology technicians, machinists, and quality control personnel are the primary installers.

This contact point is suited for shop-floor and inspection-room use wherever dial indicators are deployed for runout checks, surface comparison, bore alignment, or fixture verification. The ruby tip material resists wear on hard workpiece surfaces, making it appropriate for high-cycle measurement routines on hardened steel, carbide, or ceramic components. It threads directly into the AGD Group 1 indicator spindle using the standard 4-48 thread without adapters or additional hardware.

Key Features

• Ruby contact tip material for extended wear life on hard surfaces
• Cupped ball geometry for stable contact on round and spherical features
• 4-48 thread fits AGD Group 1 dial indicator spindles
• 0.75 inch contact point length for standard reach applications
• 4 mm ball diameter suits a wide range of workpiece curvatures

Compatibility

Designed for use with dial indicators accepting a 4-48 threaded contact point per the AGD Group 1 standard. Consult your indicator manufacturer documentation to confirm thread specification before installation.

Installation Notes

Installation is performed by machinists, metrologists, or quality technicians servicing dial indicator assemblies. Remove the existing contact point by unscrewing it from the indicator spindle, then thread the 20-350-5 in by hand until snug. Do not overtighten, as excess torque can damage the spindle threads on the indicator. Verify indicator zero and calibration after any contact point change before returning the instrument to service.