Universal Metal Spinning Company, Inc. – since 1963

Manufacturer of Aluminum Spheres for Radar Target Tracking & Calibration.


Calibration and Target Spheres Available in Dimensions from 3.187″ – 27.5″. Our Spheres are Hand Spun for the Lowest Weights Available.


Universal’s aluminum radar target spheres are constructed from two hand spun hemispheres. The hemispheres are jigged and welded into a compete sphere, then sanded and polished to a smooth spherical surface.

We define sphericity as the largest difference in diameters obtained when a large number diameter measurements are taken, i.e.,

sphericity = largest diameter minus smallest diameter.

We polish all of our radar calibration spheres to provide a consistent, smooth finish, providing the best performance for tracking and calibration of your systems.

Aluminum radar target spheres

Check out the specifications data table below for our standard sizes of Target Spheres.

Class A Spheres
Stock # Diameter (inches/cm) Weight Sphericity
003.187-A 3.187″/8.09 cm 5 oz. .015″
004.75-A 4.75″/12.07 cm 6 oz. .015″
005.42-A 5.42″/13.77 cm 7 oz. .020″
006-A 6.00″/15.42 cm 8 oz. .020″
008-A 8.00″/20.32 cm 21 oz. .020″
010-A 10.00″/25.4 cm 23 oz. .025″
012-A 12.00″/30.5 cm 32 oz. .030″
014-A 14.00″/35.56 cm 44 oz. .035″
020-A 20.00″/50.8 cm 112 oz. .050″
025.125-A 25.125″63.8 cm 178 oz. .100″
027.5-A 27.5″/69.9 cm 280 oz. .100″

Contact Us Today for More Information about our Aluminum Radar Calibration and Target Spheres!

NOTE: U.S. Orders Only!