Mahr Federal A21 Dial Indicator

The Mahr Federal A21 Dial Indicator is a precision hand gauge that translates spindle movement into a readable dial, offering 0 to 0.25 in of travel with 0.0001 in resolution. This instrument is designed for metrology and shop inspection, allowing quick assessment of tiny displacements to verify part conformity and machine alignment. With a 0.25 inch range and 0.0001 inch graduations, the A21 delivers fine sensitivity for checking runout, squareness, and fixture positioning during setup and inspection tasks. The simple analog readout enables technicians to monitor deviations on parts, fixtures, or assemblies and record direct measurements without requiring digital instrumentation. In typical manufacturing and calibration workflows, dial indicators are used to gauge relative displacement when mounting parts, checking surface flatness, or verifying consistency of machined features across batches. The A21’s design supports repeatable readings within its specified travel and resolution, making it a practical choice for quality control environments where quick, clear indications of small variances are needed.