Estes BOSS Kit #7316, Build, Part 7, Forward Centering Rings

Sand off and sand flat the lowest facing 50/55 centering ring. A smooth, flat face will give you a better fit of the 12 small vanes against the ring.

After sanding, seal the smooth face with a light coat of wood glue and final smooth sanding.

The lower tube is marked for the fins,

the upper tube is marked for the 12 vanes.

Here's where the lower ring (smooth face is to the rear) will sit. Note the pencil lines for the vanes.

The gluing lines had any remaining filler/primer scraped off for a stronger glue bond.

Notice the extended pencil lines over and onto the green centering ring. With the vanes in place you'll be covering up the pencil lines. The extension of the lines gives you a straight line reference beyond the top of the vanes.

The upper ring is glued on even with the top of the BT-50 tube.

I use the flat surface of my sanding block to even up the two edges.