Buck, This is a two piece hub. The dia. of the adapter that mates to the prop is 1.20". I took some pictures of it and posted them on the Echo 2400T post. Post # 133. It was made by Roy Sholl. I didn't keep the disk I recorded it on, I usually format and reuse them. If you want to search you can see how it is made. It really looks good I was just concerned about the Surface area against the prop.

Later George