Spi 20-703-5 Dial Drop Indicator 1 in 0.001 Grad

Product Description

The SPI 20-703-5 is a dial drop indicator designed for precision dimensional measurement in machine shop, toolroom, and quality control environments. It delivers a 1 inch measuring range with a 0.001 inch graduation, providing reliable readings across a 2-1/4 inch white dial face with dual reading scales of 0-100 and 0-50-0. The rigid, forged brass housing resists wear and holds calibration under repeated use. A revolution counter tracks full-range travel, and the unit ships with a Certificate of Calibration Traceable to NPL, making it ready for use in environments that require documented traceability. Machinists, metrologists, and quality technicians are the primary users.

This indicator is suited for surface runout checks, part height comparisons, fixture verification, and setup work on mills, lathes, and surface plates. The flat and lug back mounting options give it flexibility across standard indicator holders, magnetic bases, and custom fixtures. At 0.1 inches of travel per revolution, it is appropriate for general-tolerance work where 0.001 inch resolution is the required increment. The included tolerance pointers allow quick pass-fail visual reference without additional tools.

Key Features

• 1 inch measuring range with 0.001 inch graduation for general-tolerance dimensional inspection
• Dual dial reading scales: 0-100 and 0-50-0 for flexible reading conventions
• Revolution counter tracks cumulative travel across the full 1 inch range
• Rigid, forged brass housing for durability and calibration stability
• Flat and lug back mounting compatibility for use with standard indicator holders and magnetic bases
• Includes Certificate of Calibration Traceable to NPL and tolerance pointers

Compatibility

Designed for use with standard AGD Group 2 indicator holders, magnetic base arms, and fixtures accepting a 0.375 inch stem diameter and a No. 4-48 thread. Meets AGD Group 2 and ASME B89.1.10M-2001 standards.

Installation Notes

Secure the indicator stem in a rigid holder or magnetic base before zeroing to prevent false readings from vibration or flex. Verify the contact point is perpendicular to the measurement surface to avoid cosine error. Do not force the spindle beyond its rated 1 inch travel range, as overtravel can damage the movement. Calibration should be verified periodically against gauge blocks or a reference standard traceable to a national metrology body.