Dial Indicators

Dial indicators are precision measuring instruments that convert small linear displacements into angular movement of a pointer on a graduated dial. They are used to measure runout, flatness, parallelism, concentricity, and surface variation on machined parts, fixtures, and assemblies. Standard dial indicators typically offer resolution of 0.001 in or 0.01 mm, while test indicators and digital models provide finer resolution for demanding metrology applications. The plunger-style and lever (test) indicator are the two main types, each suited to different measurement setups.

Dial indicators are commonly mounted on magnetic base stands, surface plates, comparator stands, or CMM fixtures to measure relative displacement rather than absolute dimension. They are widely used in machine tool setup, fixture alignment, incoming inspection, and assembly verification. Digital dial indicators with Digimatic or RS-232 output can feed data directly into SPC systems for process control and quality documentation.

Typical Applications

Checking spindle runout, chuck runout, and workpiece eccentricity on lathes and machining centers
Measuring flatness and parallelism of precision-ground surfaces on surface plates
Aligning machine tool fixtures, vises, and workholding devices during setup
Verifying assembly stack-up and part-to-part variation in production inspection
Comparative gauging against master parts in high-volume manufacturing environments

Popular Brands

Starrett is widely regarded for its high-quality dial and test indicators favored in toolrooms and inspection departments. Mitutoyo offers a broad range including Digimatic indicators with SPC output. Mahr and Swiss-made Tesa indicators are preferred in European precision metrology, while Brown & Sharpe and Fowler are common in general-purpose industrial applications.