So I made up some juggling balls.
These puppies are made using a modified version of the Japanese Ball design. Each one is three layers thick, with the center layer being steel rings, and the outer two being anodized aluminum. It took some time to figure out the correct ARs for each layer, but the end result is some perfectly solid, durable juggling balls. Eahc one is 2 inches in diameter and 2.8 oz in weight.
I stress tested the prototypes by throwing them at different things, and they only started to show visible wear after being thrown at concrete more than a few times. It was quite cathartic.
Like 'em? They're for sale on etsy:[link]