Spi 21-230-8 Radius Contact Point Dial Indicator

Product Description

The SPI 21-230-8 is a radius-style contact point designed for use with dial indicators in precision measurement applications. Manufactured from black oxide steel, it threads directly onto the indicator spindle using a 4-48 thread and measures 3/16 inch in diameter with a contact point length of 5/8 inch (0.6250 inch). The radius tip style allows consistent contact on curved or irregular surfaces, making it a reliable choice for dimensional inspection work. Installation and swap-out is straightforward, suiting metrology technicians, machinists, and quality control professionals who need dependable tip geometry for repeatable readings.

This contact point is intended for dial indicators classified under AGD Group 1. It is a direct-fit replacement or supplemental tip for standard dial indicator spindles with 4-48 threading. Typical applications include surface plate inspection, fixture gauging, and in-process dimensional checks on machined parts. The radius contact geometry is well suited for measuring shaft diameters, bores, and other contoured features where a flat or ball-end tip might rock or seat inconsistently.

Key Features

• Radius contact tip style for consistent seating on curved and contoured surfaces
• Black oxide steel construction for corrosion resistance and durability in shop environments
• 4-48 threaded shank compatible with AGD Group 1 dial indicator spindles
• Contact point length of 5/8 inch (0.6250 inch) for standard depth reach
• 3/16 inch diameter tip provides a defined contact area for repeatable measurement

Compatibility

Designed for use with dial indicators that accept 4-48 threaded contact points, conforming to AGD Group 1 industry designation standards.

Installation Notes

Installation is performed by a machinist or metrology technician using the appropriate small spanner wrench or contact point tool to thread the point onto the dial indicator spindle. Avoid over-tightening, which can damage the fine 4-48 thread on the spindle. Ensure the indicator is removed from the fixture or stand before swapping contact points to prevent accidental deflection of the spindle. Clean the spindle threads before installation to ensure full seating and accurate zero.