Estes Curvilinear #3231, Build, Parts 2, 18mm Engine Mount

Here's the parts for the 18mm mount. I'll be doing my replaceable Kevlar mount on this one.
Hang onto the kit's 13mm mount. You'll need it to figure out the Center of Gravity from the original 13mm design.

The 20/60 centering rings are from BMS and cut from black Letramax board.
After punching out the engine hook relief holes, the tips were cut off to square off the sides.
Directly on the other side is the Kevlar tube holes, leave these as is.

On the left is the lower ring with the larger engine hook slot.

On the right is the upper ring. There is a very small partial punch to go over the top of the engine hook.

The inside of the centering rings were a little large for the BT-20 engine mount tube.
To bring down the inside diameter a ring of glue was applied and allowed to dry. This little bit of glue gave a good friction fit over the BT-20 tube.