What do I do before starting a drive cleat?

Line up the two drive hems first. The drive should slide over both hems straight; it is not supposed to pull a badly misaligned duct joint together by itself.

Start the drive only after the joint is lined up. The drive should guide the hems together, not fight a crooked setup.

Rectangular Duct & Fittings 2nd Year YELLOW

Stop if

Ask when the drive hems will not line up after support and minor adjustment, or if the duct appears wrong size/out of square.

Watch out

Do not hammer a drive onto a joint that is already crooked.

Check

Support both sections
Square the ends
Make sure the S side is seated before driving

Steps

Support both duct sections so the weight is not hanging on the joint.
Check that the hems are parallel and close enough to start.
Start the drive square with light taps.
Watch the first few inches
if it walks crooked, stop and reset.
Finish only after the joint stays aligned.

Say this to your foreman

In Rectangular Duct Assembly: S-and-Drive, I'm looking at: What do I do before starting a drive cleat? What should I verify before I cut, drill, seal, cover, move, or install?