Set of paired hardened and lapped precision balls made of chrome steel, supplied in a practical plastic-coated case to protect each element and keep all sizes clearly organised and easy to identify. The set includes 25 pairs of balls with diameters from Ø1 to Ø25 mm and is designed for metrology, quality control and high-precision measurement applications in workshops, inspection rooms and production departments.

The balls are manufactured from ground and lapped chrome steel, providing high hardness, good wear resistance and excellent dimensional stability during use. Their accurate finish and tight tolerances allow them to be used as dimensional references for comparative checks, geometric inspections, indirect measurements and measuring instrument calibration. With an accuracy of 0.0025 mm, dimensional tolerance below 2.5 μm, roundness below 0.6 μm and surface roughness below 0.05 μm, this set is suitable for applications where reliable and repeatable measurement results are required.

Paired precision balls are commonly used for checking holes, grooves, seats, internal profiles, surfaces and complex mechanical components. When placed inside a bore or cavity, they allow indirect diameter measurements, symmetry checks, form inspections and geometric verification. Used together with micrometers, calipers, dial indicators, bore gauges or coordinate measuring machines, they help improve inspection accuracy and make it possible to detect dimensional errors, fitting clearances, form deviations or machining irregularities.

Thanks to their hardness of approximately 60±2 HRC, the balls provide good resistance to contact wear even during repeated use. They are particularly suitable for precision engineering workshops, automotive industries, maintenance departments, machine tool manufacturers, toolrooms and quality control laboratories that require reliable, compact and easy-to-use reference elements. For best results, the balls should be used on clean surfaces, protected from impacts or drops, stored in the case after use and handled carefully to preserve the lapped finish and geometric precision.