The rear mount was made from 1/8" end grain balsa fiberglasss laminate. (one of my favorite composite materials) The rear support was made from the same material and lined with a piece of fuel tubing. A hole of 1.825 inches is about right with the fuel tubing for a snug fit on the rear of the motor. They are held together with # 2 button head servo type screws. Small pieces ot gold Nyrod are used to retain the screws as in the servo mounts.

The rear former and rear support with fuel tubing and screws weigh 19 gms or .7 oz. Of course add a little weight to glue them in place.