Estes EAC Firecat #0821, Build, Part 2, Fitting The BT-48 Tube

You could simply use a standard BT-50 or a yellow spacer tube for the low intake/motor tube and nobody would notice the difference. But what fun it that? 

Tube cutting experience should be part of your rocketry skill set. The diameter of the 2 1/2" long BT-50 tube will have to be smaller to slide into a standard BT-50, like a coupler.

 

Use your aluminum angle to draw a straight pencil line down the length of the tube.

You can use the angle as a guide to cut the first line.

Slide the slit tube into the longer BT-50 and note the overlap. The overlap will have to be cut off.

Slide the slit tube halfway into the main BT-50 tube.

Trace down the overlap halfway down. Flip over the tube and trace the other side.

You might end up with angled lines. It's difficult to get a straight line because the tube shifts.

I prefer to cut the second line with scissors. It's better to cut inside the pencil line a little wide at first.

I used my sanding block to clean up the line to fit into the BT-50.

Here's a good fit of the new "BT-48" tube slide into the main BT-50H. 

The segment joint is clean and the slit tube slides easily into the BT-50H.