On my recent trip to a local antique mall I saw this guy.
To start the project I lined up the hoops by size and marked the center point on each one with a small blue dot (you can see in photo 2 above). You will notice that one hoop in all three sets has the adjustor metal piece at the top. This hoop should go on the outside and be used to make the hoop large enough for the other two to fit inside and then tightened closed during the glue step. I started with the 12" hoops and put the two with no metal closure inside one another and lined up the dots that note center. I applied glue here and at the top midpoint. I clamped them together with some wood(?) clips we had in the garage. I let them dry for about 30 minutes to make sure the glue would hold before the next step. Turns out, this isn't necessary. The glue is powerful!