Enerjet by Aerotech, Astrobee D Build, Part 4, Engine Mount

The fin-lock centering rings are a tight fit on the engine mount tube.

I scraped the inside walls with a #11 blade until I got a good fit.

These rings are molded to fit tightly but I didn't want to distort the engine mount tube.

Here's a dry fit, no glue yet.

This kit no longer includes an engine hook or thrust ring (engine block) A revision sheet explains the changes and which steps to skip.

Pay attention to the positions of the rings. 

From the rear edge of the engine mount tube:

At 1 1/2" is the front edge of the rear fin-lock ring.

At 3 9/16" is the rear edge of the forward fin-lock ring.

With the rings slid in place, make sure both the rings are in line and the fin tab fits into the notches in the fin-lock rings.

You are instructed to make four 1/4" cuts, spaced 90 degrees in the top of the tube. This allows the baffle shoulder to slide into the top of the tube.

Mark the cuts with pencil first.

You can get closer to a 90 degree spacing using a single edge razor blade.

No ejection wadding is needed on Enerjet by Aerotech rockets.

The permanent cooling mesh is stretched out to 6" in length.

Insert it into the front end of the tube.