Bill. Received your email but not sure if you are getting mine back as I’m getting failure notices on the replies.
My material of choice for making hubs is ‘cold roll’ steel and go out of my way to not use ‘hot roll’. Aluminum is also an option for the hub itself. The bolt circle for the damper attaching bolts is 3.250” but one hole is offset so it’s easier to simply use transfer punches to locate the damper holes to the semi-finished hub than go to the trouble of indexing the holes in the hub on a rotary table or lathe. Here’s a couple of pics of the hub that allows the ATI damper shell to be used on a Y.
Lorena, Texas (South of Waco)