We did attempt a couple of whistles at Kingfest today, with limited success. The smaller jaws on the chuck that Dirk provided worked great, and the live cone center worked as expected.
We did not have any 3/8" dowel material on the trailer, and I did not think to grab some from my house before heading over this morning. We did attempt to turn material to fit, but that was not good either. We did find some 1/4" dowels in the trailer, and that worked well with the blanks I had prepared. We had to sand down the flat for the insert, as there was not a hand-plane in the trailer. The sander was too much and could not control well the amount to take off.
Berta has dowels on her shopping list, and Dirk gave her the model of chuck/jaws that he brought today.