Spi 20-338-0 Cupped Ball Contact Point 3mm 4-48 Thread

Product Description

The SPI 20-338-0 is a cupped ball contact point designed for use with dial indicators in precision measurement applications. Machined from solid carbide, this contact point provides a durable, wear-resistant tip that maintains accurate readings over extended use. It features a 4-48 thread size for secure attachment and measures 0.75 inches in length with a 3 mm ball diameter. The cupped ball geometry seats consistently against rounded or irregular workpiece surfaces, making it a reliable choice for quality control technicians and machinists who depend on repeatable indicator readings.

This contact point is suited for dimensional inspection, surface runout checks, and setup verification tasks in machine shops, toolrooms, and manufacturing environments. It conforms to AGD Group 1 standards, which govern the interface dimensions for dial indicators commonly used in industrial metrology. Technicians working with standard AGD-compatible dial indicators will find this a direct fit for routine replacement or application-specific tip changes.

Key Features

• Solid carbide construction for long service life and wear resistance
• Cupped ball contact geometry for consistent seating on curved or irregular surfaces
• 3 mm ball diameter for precise point contact
• 4-48 thread for secure, tool-free hand-tightening onto standard indicator stems
• 0.75 inch contact point length
• Meets AGD Group 1 industry designation for broad dial indicator compatibility

Compatibility

Designed for use with dial indicators meeting AGD Group 1 specifications. Fits indicators with a 4-48 threaded contact point stem.

Installation Notes

Installation is performed by hand-threading the contact point onto the dial indicator stem — do not use pliers or wrenches directly on the ball tip, as this can damage the carbide surface. Before replacing a contact point, zero the indicator and verify the new tip length matches the original to avoid offset errors in your measurement setup. No special tools or trade licensing are required, though contact point selection and indicator setup should follow the metrology procedures established at your facility.