A drive cleat pops off the tight inside throat of a 45-degree elbow

The inside throat of an angled fitting can be under tension. Align and clamp the flanges before driving the cleat, and trim/detail only as approved.

Rectangular Duct & Fittings 1st Year GREEN

Watch out

Do not beat a drive cleat until it buckles and leaves the throat joint loose.

Check

Check whether flanges are aligned and seated.
Look for the drive bottoming out at corner seams.
Clamp the throat joint flat before driving.
Check cleat length and end clearance.
Seal only after the drive is mechanically seated.

Steps

Check whether flanges are aligned and seated.
Look for the drive bottoming out at corner seams.
Clamp the throat joint flat before driving.
Check cleat length and end clearance.
Seal only after the drive is mechanically seated.

Say this to your foreman

The drive cleat is popping off the inside throat of this 45 elbow. I can clamp the flanges flat and reset the cleat, but it may need a small approved trim. Do you want me to correct it now?