Spi 21-528-5 Horizontal Dial Test Indicator Nist

Product Description

The SPI 21-528-5 is a horizontal dial test indicator designed for precision dimensional measurement in machine shops, tool rooms, and metrology applications. It covers a measurement range of 0 to 0.06 inches with a dial graduation of 0.0005 inches, enabling fine surface variation and runout readings. Accuracy is rated at 0.0012 inches. The jeweled bearing movement supports smooth, repeatable deflection, and the rotating dial with automatic reversal allows the indicator to be zeroed and read from either direction without removing it from the setup. A NIST traceable short-form calibration certificate is included.

This horizontal-style indicator mounts via a dovetail attachment, the standard interface for indicator holders, arm-type holders, and magnetic base systems used throughout precision machining and inspection setups. It is suited for checking runout, surface parallelism, concentricity, and part positioning on milling machines, lathes, surface plates, and CMM fixtures. The 0-15-0 dial reading, white dial face, and 1.1875-inch dial diameter make the scale easy to read under typical shop lighting. The built-in revolution counter tracks total travel across the 0.06-inch range. This indicator is typically set up and used by machinists, toolmakers, quality control technicians, and precision inspection personnel.

Key Features

• 0 to 0.06 inches measurement range with 0.0005 inch graduations for fine resolution
• Jeweled bearing movement for smooth, low-friction deflection and long service life
• Automatic reversal mechanism allows bidirectional measurement without repositioning
• Rotating dial with 0-15-0 reading and built-in revolution counter for total travel tracking
• Dovetail mount compatible with standard indicator holders and magnetic base arms
• NIST traceable short-form calibration certificate included out of the box

Compatibility

Designed for use with standard dovetail-style indicator holders and magnetic base systems common to precision machining and inspection environments.

Installation Notes

Mount the indicator into a dovetail holder or compatible arm and secure it firmly before zeroing the dial. Ensure the contact point approaches the workpiece at the correct angle to avoid side-loading the spindle, which can affect accuracy. The contact point swivel angle of 210 degrees provides flexibility in positioning. Always calibrate or verify the indicator against a known reference before taking critical measurements.