Starrett 51177 Micrometer Ball Anvil 0.25 Inch Diameter

Product Description

The STARRETT 51177 is a ball-type replacement anvil designed for use with Starrett outside micrometers. The anvil features a 0.25-inch anvil diameter and a 0.20-inch cap diameter (5.00 mm), providing a precise contact point for accurate measurement. At 0.008 pounds, this compact accessory is machined to maintain the measurement integrity of the micrometer it serves. It is installed by metrology technicians and precision measurement professionals who require a reliable contact surface for measuring curved or irregular workpieces. The ball anvil geometry allows accurate readings on concave or radiused surfaces where a flat anvil face would not seat correctly.

This ball anvil is suited for precision measurement applications in manufacturing, machining, tooling, and inspection environments. It is a direct replacement or spare component for specific Starrett micrometer models and is appropriate for both shop-floor and laboratory settings where consistent contact geometry is critical to measurement accuracy.

Key Features

• Ball-type anvil geometry for measuring curved and irregular surfaces
• Anvil diameter of 0.25 inches for consistent contact point
• Cap diameter of 0.20 inches (5.00 mm) for proper fit to compatible micrometer frames
• Lightweight at 0.008 pounds — minimal mass addition to the micrometer assembly
• Catalog Industry Number 247D for cross-reference verification

Compatibility

Designed for use with Starrett 216, 231, 436.1, 733, 734, 3734, 1212, and 1230 series micrometers as specified by the manufacturer.

Installation Notes

Installation is performed by metrology technicians or precision tool service personnel familiar with micrometer maintenance. Before replacing the anvil, ensure the micrometer is clean and free of debris at the anvil seat. Use only hand tools appropriate for precision instrument work and avoid applying excess force that could damage the spindle or frame. Verify calibration and zero the instrument after anvil replacement before returning it to service.