This ball turner is the over the top type. T have several boring heads laying around, so this was my quick and easy way to put together a ball turner. The arbour was a M/T #3, and I just turned it down straight. The holder was a spare boring bar holder for the QCTP, so no point making what I already have. The only parts I had to make, were the hub that attaches to the end of the arbour, and a handle to attach to the hub. I also machined up a holder to use the carbide insert.
Quick and dirty, but why not just use stuff that is laying about anyway?