I would drill it 4x4, as it will give some hook when needed, but you can still make it roll as a spare ball when needed. Mine is drilled that way, and it is awesome, I want another so I can drill it a bit stronger, and keep the 4x4 for spares and bone dry.
Dave
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Regardless of what the pins are made of, you can still SAW 'Em Up! Mess with F.O.S. and get CUT like all the rest!!
F.O.S. Members, Our Assignment Should We Choose To Accept It, Polish and Sharpen Up Our Saws; Pins Have Been Spotted, and We Are To Saw 'Em Up!!