Spi 20-642-5 Drop Indicator Contact Point Extension

Product Description

The SPI 20-642-5 is a steel contact point extension designed for use with drop indicators and dial indicators. It extends the reach of a standard contact point to allow measurement in recessed bores, deep cavities, and hard-to-reach features on a workpiece. The extension measures 1-3/4 inches in length and threads on using a 4-48 thread, the standard thread size found on most dial indicator contact point stems. Machinists, tool-and-die technicians, and metrology professionals keep these extensions on hand for setups where the standard contact point cannot reach the measurement surface without interference.

This extension is suited for precision measurement applications in machine shops, tool rooms, and quality control environments. It threads directly onto the contact point stem of a dial indicator, adding 1-3/4 inches of reach without requiring a separate adapter. Steel construction provides the durability and dimensional stability needed for repeatable measurements. The 4-48 thread is a universal fit across the broad majority of dial indicators used in trade and manufacturing settings.

Key Features

• Steel construction for durability and dimensional stability in precision measurement work
• 1-3/4 inch extension length for added reach into recessed features and deep bores
• 4-48 thread size matches the standard contact point stem thread on most dial indicators
• Compatible with drop indicators and standard dial indicators
• Compact form factor minimizes deflection during measurement

Compatibility

Designed as a standard 4-48 threaded contact point extension compatible with any test indicator or dial indicator accepting a 4-48 contact point stem thread.

Installation Notes

Installation requires no special tools. Thread the extension onto the contact point stem by hand, ensuring full thread engagement without overtightening, which can damage the fine 4-48 thread. Remove the existing contact point before attaching the extension, then reattach the contact point to the free end of the extension. Verify indicator zero and re-calibrate the setup before taking measurements, as adding an extension changes the effective contact height.