Dial Bore Gages - Mitutoyo

Mitutoyo Holtest Dial Bore Gages are high-precision internal micrometers designed for fast, accurate measurement of inside diameters in bores, holes, and cylindrical features. Known for their reliability and repeatability, Holtests are widely used in machining, aerospace, automotive, and quality control applications where tight tolerances are critical.

At the core of the Holtest design is a self-centering three-point measuring system. Three hardened anvils, evenly spaced at 120°, automatically align with the bore axis to deliver true, consistent measurements with minimal operator influence. This design ensures superior accuracy compared to traditional two-point measurement methods and allows for direct reading of internal dimensions without complex setup.

Mitutoyo Holtest Dial Bore Gages are engineered for durability and long-term performance. Titanium Nitride (TiN)-coated contact points provide excellent wear resistance and allow measurements to be taken close to the bottom of blind holes, while carbide-tipped anvils enhance strength and longevity. A built-in ratchet stop mechanism applies constant measuring force, ensuring repeatable results regardless of user technique.

Available in both mechanical and digital (Digimatic) models, Holtests offer flexibility to match your inspection needs. Mechanical versions provide dependable, shop-floor ruggedness, while digital models feature easy-to-read displays and SPC data output for streamlined data collection and process control. Optional extension rods enable deep-hole measurement, and setting rings are available for precise zero calibration.

From small precision bores to large diameter applications, Mitutoyo Holtest Dial Bore Gages deliver the accuracy, durability, and confidence required for critical internal measurements.