Starrett 50991 Micrometer Calibration Standard 12 in

Product Description

The STARRETT 50991 is a spherical end micrometer calibration standard designed for verifying and calibrating outside micrometers in precision measurement applications. At 12 inches in length, it provides a long-range reference with accuracy up to 0.000170 inch, making it suitable for high-tolerance inspection work in tool rooms, calibration labs, and production environments. The unit ships calibrated and includes a heat insulating handle to prevent dimensional error caused by thermal expansion during handling. Machinists, metrologists, and quality control technicians rely on this standard to maintain traceable measurement accuracy.

This calibration standard is used in toolroom and metrology settings where micrometer calibration and verification must meet tight tolerances. The spherical end design ensures consistent contact geometry during measurement checks. It is appropriate for use in both production quality control environments and dedicated calibration labs. The included heat insulating handle is a practical feature for bench technicians who need to hold the standard during extended calibration sessions without introducing thermal drift.

Key Features

• 12-inch overall length provides long-range calibration reference for outside micrometers
• Accuracy up to 0.000170 inch for high-tolerance verification work
• Spherical end geometry ensures repeatable contact during calibration checks
• Ships calibrated for immediate use in quality control or metrology applications
• Heat insulating handle minimizes thermal expansion error during handling

Compatibility

Designed for use with outside micrometers requiring a 12-inch calibration reference. Suitable for standard micrometer calibration and verification procedures in toolroom and inspection environments.

Installation Notes

This standard is handled and used by metrologists, tool room technicians, and calibration professionals rather than installed. Always allow the standard to reach ambient temperature before use to avoid thermal expansion errors. Store in a protective case away from temperature extremes and humidity. Handle only by the heat insulating handle to prevent body heat from affecting dimensional readings.