Omega BT50 Test Arbor is a precision master mandrel designed for BT50 tooling and spindle alignment. With a 50 mm diameter and 350 mm gauge length, it provides a stable reference for calibration, runout checks, and setup verification in workshops and production environments. Listed as BT MAS403 (JIS 6339) Master Mandrel, it is designed for compatibility with standard BT50 tooling.

• 50 mm diameter for stability: A robust diameter minimizes flex during measurements, delivering repeatable readings and reducing variability across tools and sessions.
• 350 mm gauge length for flexible setups: The extended reach lets you work with larger fixtures and longer tooling paths without constant repositioning, speeding up calibration and setup tasks.
• BT50/JIS 6339 master mandrel accuracy: Engineered to tight tolerances as a master reference, providing reliable alignment and repeatable results across machines and applications.

With this BT50 Test Arbor, you get a dependable reference that helps tighten tolerances, cut setup time, and improve measurement consistency across your milling, turning, and inspection workflows. Its combination of precise dimensions, standard compatibility, and robust construction supports efficient, accurate calibrations and reliable fixture alignment—so you can trust every setup and every check, day after day.