The S-and-drive cleat will not seat or keeps stopping halfway
Stop hammering harder. Check alignment, squareness, S-cleat seating, drive direction, raw edges, and whether the duct is being pulled crooked by weight or support.
Do not mushroom the drive, crush the duct corner, or hide a bad fit-up with mastic.
Check
Check that both duct ends are square and lined up.
Verify S-cleats are fully seated and facing the right way.
Check that the drive is straight and not catching on bent metal.
Support the duct so weight is not opening the joint.
Ask before bending, cutting, or burying the gap with mastic.
Steps
Check that both duct ends are square and lined up.
Verify S-cleats are fully seated and facing the right way.
Check that the drive is straight and not catching on bent metal.
Support the duct so weight is not opening the joint.
Ask before bending, cutting, or burying the gap with mastic.
Say this to your foreman
The drive is stopping halfway at [location]. The joint looks aligned/not aligned and the S-cleat is [condition]. Do you want me to reset the joint, adjust support, or replace the drive?