I posted this thread as a resource for people with bores 1.67", 2.59", and 3.5". This company makes zinc balls in these sizes clean and new. http://www.rotometals.com/category-s/77.htm
They also do custom castings apparently. If I am not mistaken and correct me if I am Zinc doesn't spark. So no need to wrap it in anything.
They also do custom castings apparently. If I am not mistaken and correct me if I am Zinc doesn't spark. So no need to wrap it in anything.

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