Before gluing the leather collar to the wheel collar, you should hand stitch the leather collar to the "boomerang." This looks much more complicated than it is. Use the hook needle and upholstery thread to essentially stitch the stitches together. This means hooking the needle under the exposed thread on the boomerang and collar in a zig-zag pattern. There is no need to pull the thread super tight as you do not want the seam to look too bunched up. Start at the collar joint and work around.