Spi 21-236-5 Radius Button Contact Point Dial Indicators

Product Description

The SPI 21-236-5 is a radius button contact point designed for use with dial indicators in precision measurement applications. Threaded to a 4-48 specification, this contact point measures 0.50 inches in diameter with a contact point length of 0.25 inches. Constructed from black oxide steel, it provides durability and corrosion resistance in shop and field environments. The AGD Group 1 industry designation ensures it meets standardized dimensional requirements for interchangeability with compatible indicator stems. Metrology technicians, machinists, and quality control professionals install this type of accessory when replacing worn or application-specific contact points on existing dial indicator setups.

This contact point is suited for dimensional inspection, surface runout checks, bore measurement, and general gauging tasks where a radius-style button tip is preferred over a flat or pointed contact. The radius button profile distributes contact load across a curved surface, which is beneficial when measuring soft materials or curved workpiece surfaces. It is commonly used in tool rooms, machine shops, and quality assurance stations where AGD-compatible dial indicators are standard equipment.

Key Features

• 4-48 thread size for direct installation on AGD Group 1 dial indicator stems
• Radius button contact style provides consistent contact on curved and flat surfaces
• Black oxide steel construction resists corrosion and wear in shop environments
• 0.50 inch diameter button with 0.25 inch contact point length for compact clearance in tight measuring setups
• Meets AGD Group 1 industry designation for standardized fitment

Compatibility

Designed for use with dial indicators requiring a 4-48 threaded contact point, conforming to AGD Group 1 industry standards.

Installation Notes

Installation is performed by machinists or metrology technicians using the appropriate small wrench or contact point tool to thread the point onto the indicator stem by hand before final snugging. Do not overtighten, as excessive torque can damage the delicate 4-48 threads on the indicator spindle. Ensure the indicator is removed from active service and secured before swapping contact points to prevent accidental deflection or damage to the instrument.