Spi 21-231-6 Drop Indicator Radius Contact Point 4-48

Product Description

The SPI 21-231-6 is a drop indicator radius contact point designed for use with dial indicators in precision measurement applications. Machined from black oxide steel, this contact point features a 3/16 inch diameter and a contact point length of 0.825 inches. It threads in at a 4-48 thread size and meets AGD Group 1 industry standards. The black oxide finish provides corrosion resistance and reduces light glare during use. Dimensional inspection technicians, machinists, and quality control professionals install and use this contact point as part of routine gauge setup and measurement work.

This contact point is suited for dimensional measurement tasks in machine shops, manufacturing facilities, and quality inspection environments. It fits dial indicators that accept standard AGD Group 1 accessory contact points with a 4-48 thread. Typical applications include surface runout checks, bore measurement setups, and part feature inspections where a radius-style tip is preferred over a flat or pointed contact for consistent surface contact.

Key Features

• Radius contact point style for consistent surface contact during measurement
• Black oxide steel construction for durability and corrosion resistance
• 4-48 thread size compatible with AGD Group 1 dial indicators
• Contact point length of 0.825 inches for standard reach applications
• 3/16 inch diameter contact point tip
• Meets AGD Group 1 industry designation

Compatibility

Designed for use with dial indicators that accept AGD Group 1 contact points with a 4-48 thread size.

Installation Notes

Installation is performed by machinists or metrology technicians during dial indicator setup. Thread the contact point into the indicator spindle by hand first, then snug with appropriate tooling — do not overtighten, as this can damage the spindle threads or affect indicator accuracy. Verify the indicator reads zero correctly with the new contact point seated before taking measurements. Store contact points in a protected case to prevent tip damage when not in use.