Estes Advanced Target Drone, Kit #1913, Build, Part 7, Fixing The Intake Slot

On a new print of the intake shrouds, 

I punched a round hole at the front of the intake slot to match the rounded leading edge of the wing fins.

I used the rotary punch.

The folds are indicated by a dashed line.

I used the round tip of a butter knife to emboss the line and start the fold.

The very tip of the knife should be smooth with no serrations.

TIP: Make the embossed lines before cutting the outside lines of the intake. It's easier to do the embossing now.

Here you can see the embossed lines.

Pre-embossing gives you a sharp, clean fold.

My Sharpie barrel was used to make a sharp crease.