Spi 20-971-8 Ball Needle Contact Point Dial Indicators

Product Description

The SPI 20-971-8 is a ball needle contact point designed for use with dial indicators in precision measurement applications. Machined from chrome alloy steel, it features a 0.75 inch contact point length and a ball diameter of 0.0313 inches at the tip. The 4-48 threaded shank conforms to AGD Group 1 industry standards, making it a direct-fit replacement stylus for compatible dial indicator stems. Metrology technicians, machinists, and quality control inspectors use this contact point when checking bores, surfaces, and runout in shop or inspection environments.

This contact point is suited for light-duty precision measurement tasks in machine shops, tool rooms, and quality assurance stations. It is compatible with dial indicators that accept AGD Group 1 accessories with a 4-48 thread. Applications include surface inspection, part alignment, and fixture verification on both manual and automated measurement setups. The small ball tip diameter allows access to confined measurement surfaces where standard flat or button contacts cannot seat properly.

Key Features

• Chrome alloy steel construction for durability and wear resistance in repetitive contact applications
• 0.75 inch contact point length provides clearance in recessed or hard-to-reach measurement areas
• 0.0313 inch ball tip diameter for precise point contact on curved or irregular surfaces
• 4-48 threaded shank meets AGD Group 1 industry designation for broad indicator compatibility
• Lightweight at 0.1 pounds, minimizing added mass on sensitive indicator mechanisms

Compatibility

Designed for use with dial indicators accepting AGD Group 1 contact points with a 4-48 thread. No specific model compatibility data was provided in the product input; verify thread size and group designation against your indicator before ordering.

Installation Notes

Installation is performed by metrology technicians or machinists familiar with dial indicator maintenance. Power down any powered fixture or CNC setup before handling the indicator stem. Thread the 20-971-8 into the indicator spindle by hand and snug finger-tight — avoid over-torquing the fine 4-48 thread, which can damage the indicator stem or contact point shank. Inspect the ball tip for nicks or deformation before use, as surface damage will affect measurement accuracy.