Spi 21-284-5 Drop Indicator Dial Accessory Metric

Product Description

The SPI 21-284-5 is a drop indicator dial accessory designed for use with metric dial indicators. It provides the mechanical interface needed to extend or adapt the contact point of a dial indicator in precision measurement applications. The accessory features an M2.5 x 0.45 thread size and a 0.3-inch shank diameter, making it suitable for secure attachment to compatible metric indicator spindles. Machinists, quality control technicians, and tool-and-die professionals use accessories like this to maintain accuracy during surface, bore, or runout inspection work.

This accessory is intended for use in machine shop, manufacturing, and quality assurance environments where metric dial indicators are part of the standard inspection toolkit. It is a single-unit item suited for benchtop measurement setups, surface plate work, and fixture-mounted indicator applications. The compact profile fits into tight measurement situations where a direct spindle-to-contact connection is required.

Key Features

• M2.5 x 0.45 thread size for secure attachment to metric dial indicator spindles
• 0.3-inch shank diameter for compatibility with standard indicator holders and fixtures
• Compact dimensions: 0.5 x 0.5 x 2 inches overall
• Lightweight construction at 0.2 pounds
• Single-piece accessory with no assembly required

Compatibility

Designed for use with metric dial indicators accepting an M2.5 x 0.45 thread connection and a 0.3-inch shank diameter.

Installation Notes

Installation is performed by machinists or metrology technicians as part of indicator setup. Thread the accessory onto the dial indicator spindle by hand first, then snug carefully to avoid cross-threading the M2.5 thread. Ensure the shank is fully seated in the indicator holder or fixture clamp before taking measurements. Do not overtighten, as this can damage the fine metric thread or affect indicator calibration.