Rocketry Works
These laser cut centering rings are made from 1/8 inch birch plywood, and sized to mount a 29mm heavy wall motor tube in a 66mm (BT-80) airframe tube. The fit on the motor tube is tight, so some light sanding may be needed. Sold as a set of 2 centering...
RW-CR-29MM HW / BT-80 PW 1/8 IN