Spi 21-253-0 Flat Button Contact Point Dial Indicator

Product Description

The SPI 21-253-0 is a flat button contact point designed for use with dial indicators in precision measurement applications. Threaded at 4-48 and machined from black oxide steel, this contact point measures 0.094 inches in contact point length with a 0.25-inch diameter button face. The black oxide finish provides corrosion resistance and reduces light glare during measurement. This style of contact point is installed and replaced by machinists, metrologists, and calibration technicians working with AGD Group 1 dial indicators in quality control and inspection environments.

This contact point is suited for use in dimensional inspection setups where a flat, broad-face contact is needed to measure flat or slightly irregular surfaces. It fits AGD Group 1 dial indicators and is a direct threaded replacement for worn or application-specific contact point swaps. The 4-48 thread is the standard thread used across a wide range of dial indicator spindles in this group, making the 21-253-0 a common consumable in inspection and metrology tooling kits.

Key Features

• Flat button contact style for broad-face surface measurement
• Black oxide steel construction for corrosion resistance and reduced glare
• 4-48 threaded shank matches AGD Group 1 dial indicator spindles
• 0.094-inch contact point length for low-profile fitment
• 0.25-inch diameter button face for stable contact on flat surfaces

Compatibility

Designed for use with dial indicators conforming to AGD Group 1 specifications with a standard 4-48 spindle thread. Specific model compatibility should be verified against the indicator spindle thread specification before installation.

Installation Notes

Contact points are replaced by hand or with a contact point wrench — avoid over-tightening, which can damage the spindle threads on the indicator. Power down or depressurize any fixture holding the indicator before swapping contact points. Verify thread engagement is complete and the contact point seats flush before returning the indicator to service.