Garey, Most excellent! Appropriately limited supervision is a key factor in pedagogy. Your mill example is the equivalent to holding his bicycle seat, firm at first, then not so firm, then not at all when he finds himself at the end of the block on his own and realizes he is a rider.
I can assure you these will be memories he will treasure for a lifetime and share with his kids/grandkids.
[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]